ECONONICANALYSIS OF FEEDING
COBRA ZEBU CATTLE
IN DAHRA,
SENE.GAL
By
Kodjo Pierre Abassa
A THESIS PRESEllTED ':'0 THE GRADUATE SCHOOL
OF THE UNIVERSITY OF FLORIDA
IN
PAHTIAL FUL~ILL..iENT OF' THE R£QUIR£~lI:;NTS
FOP THE DEGREE OF MASTER OF SCIENCE
UI'!IVEFSITY OF FLORIDA
1984
/

---

ANALYSE ECONOMIQUE DES FACTEURS LIES A L'ALlMENTATION DU ZEBU
GOBRA A DAHRA, SENEGAL
THESE DE "M S"
L'elevage naisseur du Zebu gobra a Dahra est confronte a de nombreux
problemes qui sont communs aux zones saheliennes et aux pays en developpemen
Les faibles pluviometries et les longues saisons seches, les insuffisances accrues
de ressources alimentaires, les variations qualitatives et quantitatives des patura
ges soumis aux regimes pluviometriques, le manque de releves sur ces variations
qui. peuvent intervenir au cours d'une meme annee ou d1annee en annee, le man-
que d'information precis sur les besoins alimentaires des races locales, les couts
de supplementation eleves, sont quelques uns des problemes rencontres.
Les objectifs principaux de cette etude etaient de dp.terminer les besoin
alimentaires specifiques des vaches Zebu Gobra dans leurs conditions d'exploita-
tion et montrer comment les besoins alimentairesdes animaux pouvaient etre satis-
faits pendant la longue saison seche en combinant economiquement les ressources
des paturages et celles des supplements ou complements. Un modele de simulation
des besoins a ete utilise ensemble avec un modele de programmation lineaire pOUI
determiner les strategies optimales relatives a Palimentation des animaux.
Les solutions a cout minimum ont montre une diminution marquee des
couts d'alimentation par kg de veau sevre lorsque I'exploitant choisit de satis-
faire des fractions de besoins des animaux. Quels que soient I'annee de produc-
tion (annee seche, pluvieuse ou normale) et le systeme de gestion (systeme oll
100,
95,
90 ou 85 p.
100 des besoins etaient satisfaits),
les -couts dtalimenlation
augmentaient de la premiere periode (Janvier-Avril) a la troisieme periode cor-
respondant au mois de juillet.
Les capacites de charge optimales etaient estimees a 300,33, 145,70 et
433,13 hectares pour 100 tetes de vache respectivement en annees moyennes,
tres pluvieuses ou tres seches. De janvier a juillet, le phosphore et les matieres
awtees etaient les elements les plus contraignantes sur les pcHurages naturels .
. . . / ...

---

- 2 -
Pour une supplementation correcte et cl cout minimum, il faudrait
utiliser Jes
dreches, le tourteau d'arachide, les graines de coton, Puree,
la paille de sorgho et la melasse de canne. L'utilisation de denrees riches
cl la fois en proteine et en energie a eu lieu en juillet.

---

To every single member
of Abassa's family and
to Leon A. Bokovi.

---

ACKr·;O\\; LFDCi·1EUTS
I would like to express my sincere appreciation to Dr.
v!. G. Boggess, chairman of my committee, for his p:-ofes-
sional advice and assistance.
His role as en advisor went
far beyond the academic field.
It has been a gre8t pleasure
working with him.
Appreciation. is 2.1so extenced to Dr. G. \\.:.
vhn'd
2nc
Cr.
J. H. Conrad, members of my advisory committee, for their
help and encouragement.
Special t.hnnks and gratitude are due to Dr. J.
~;olt for
all the services and support he has given me during the
course of my s~udies
in food and resource economics.
SpeciAl thanks are also due to Alex Heyman for his help with
reeard to the use or the nutrient requirement simulation
mode 1.
I am grateful to the Afric8n American Institute and
U.S.
Agency for International Develoment for financing my
studies at University of Florida ~nd providing funds for
this research.
Finally,
I Hant to thank flaria Cruz for her v3luable
advice and help as an international proeram officer during
my lonE stay at the University 01 Florida.
I am also
thankful to Cindy Zimmerman,
the typist for this thesis,
for
doing such 3 good job.
i i i

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TABLE OF CONTENTS
Page
ACKNOvILEDGl,'lENTS
i i i
LIST OF rrABLES
vi
LIST OF FIGURES . . . . . . . . . . • . . . . . . . . . . . • . • . • . . . . . . . . . . . . . . . . ix
ABSTRACT
x
CHAPTER
I
INTRODUCTION
1
The Problem
1
Senegal:
Location, Topography, Climate
and Demography
4
Crop Production . . . . . • • . . . • . . • . . . . . . . . . . . . . . . . . . . . 6
Livestock Production .•.•.•.......•..•............ 8
Agricultural and Industrial Contribution
to Livestock Production •.•......•............. 14
Description of the Study Area
14
Objectives of the Study . . . • . . . . . . . . . . . . . . . . . . . . . 16
Plan of Presentation
18
11
ECONOMIC ANb BIOLOGICAL FRAMEWORK . . . . . . . . • . . . . . . 19
Economic Considerations
19
Theory of the Firm . . • . • . . . . . . . . . . . . . . . . . . . . . • . . . 21
Biological Framework . • • . . . . . . • . . . . . . . . . . . . . . . . . . 30
Growth
44
I I I
METHODS OF ANALySIS
45
....
c".
'Jl":t:-~
Nu tr i en t Requ i remen ts Si mu la tion Hode_l-
.. "'I':..
(~1e 1ton IS f.1ode 1) ....••.•..•... L.~'(,f'.... ~..7•••• 45
.
!<~,
\\ ",\\
-
EconOffilC f1odel
!,~ • •••./.. -,,,•••• '• .......).•• 5)
Th
C' •
1<.
~VI E
\\
. ;
C; :;
e
r 1 r m. • . • • . . - • - - . .. • . - - . • . • - - .:.+ - • - - - .-~ - • • •..r:1- • ." ,./
\\ C
- - - -
/
j
The LP Mod e 1 • • • • • . • . • • • • • • • . • . • . •s. .~.
. . • . . . . . . . . 5 4
,
.$ 1
,
{lJ
IV
~.
"'-."' .
le,'-
.
DA TA DE VELO PME NT •••••••••••••••••••<.I~.m.erl\\.S'~\\l•••••• 5b
Growth Da ta . . . . . . . . . . . • . • . . . . . . . • . . . . . . . . . . . . . . . 56
Forage Data
_ .. - . _ .. _
- _ .. __
50
Supplemental Feed Data
58
iv
. , - - - - - - - - - - - - - - - - - - - " - - - - " -

---

Agricultu1'Cll
cHld
lndus-::rial
By-prouucts
6C
Data Used in r']elton's r·lodel.
63
Price Data
69
· 0
V
RESULTS AND DISCUSSION . . . . . . . . . . • . . . . . . . . . . . . . . . 71
[·iutrient Requirements for Gobrc; Zebu CO ..... 5 ••..••• 73
feeding Strate~y Under Average Production
'fear
74
Feeding Strategy Under the Rainiest Year
80
Feeding Strategy Under the Driest year
86
V
SUMMARY AND CONCLUSIONS . . . . . . . . . . . . • . . . . . . . . . . . . 89
Limi t2.tions
91
Recommendations and Further Research .•..••...... 93
APPUlCIX
A
!'·10NTHLY AVERAGE NUTRIENT REQUIREfvIEI·lTS FOR
GOBRA ZEBU COWS IN DAHRA RESEARCH CENTER
95
B
OPTIMAL SOLUTION OF SUPPLEMENTAL FE~DING
100-CmJ HERD OF COBRA ZEBU
106
RL[<'LHEHCLS ••••••••••••••••••••••••••••••••••••••••••••••• 121
BIOGRAPIfICAL SKETCH
129
v
~-.I

---

LIST OF TJ\\BU~S
Table
Pnge
1.1
Selected Development rndica~ors• . . . . . . . . . . . . . . . . . . . . 2
1.2
Selected Agricultural Products:
Quantity and
Value-Added, 1980 .....•..•.•••.••..•.•.•.•...•..•..• '1
1.3.
Regional Distribution of Agricultural Products ..... 10
1.4.
Livestock Production in Senegal in Thousands of
Animals:
Inventories from 1970 Through 1979
11
1.5.
Quantity (metric tons) of Agriculturnl and
Industrial By-products Available for the
Supplemental Rations by Regions . • . . . . . . . . . . . . . . . . . . 15
4.1
Weaning Weights of Cobra Zebu Calves by
Production year . . . . . . . . . . . . . . . • . . . . • . . . . . . . . . . . . . . . 57
4.2
Nutritive Values·(AS FED) of Forage in Dahra:
Seasonal Distribution-Average Production Year
59
4.3
Nutritive' Values Used for Browse in Dahra
61
4.4.
Nutrient Concentration (AS FED) of Feeds
Available for the Formulation of Supplemental
Ra'tions."." .•. "" ... "."" •. "".""."" .. ""."." ... " ... " .. 62
4.5
Cow Age Croups and Composition of 100-Cow Herd ..... 64
4.6
Weaning Weights of Cobra Zebu Calves by Cow
~
Age Group • . . . . • . • . . . . • . • • . • • • • • • • • • . • . . . . . . . . . . • . . . b5
4.7
Cow Quality Croups . . . . . . . . . . • . • • . . . . . . . . . . . . . . . . . . . 67
4.8
~lonthly Values of Time Variables ..........•......•. 68
4.9
Distance Between Shipment Points and Related
Transportation Costs . . . . . • . . . . . . . . . . . . . . . . . . . . . . . . . 69
4.10.
Supplemental Feed Costs (FCFA)
70
5.1.
Summary of Carrying Capacity (ha) by Productio~
'I'eoie
"
""
""""""" .. """"""""""""."""" .75
vi

---

5.2.
~utrient Deficit 3S Percentog~ of Minimum
Requirement for the Various Age Classes
During the Average Production year . . . . . • . . . . . . . . . . . r/G
5.3
Optimal Average Cost (FCFA) Per KG of Calf
vi ean ec
79
5.4
Nutrient Deficit as Percentage of Minimum
Requirement for the Driest and Rainiest
Production years
81
5.5
Nutrient Deficit as Percentage of Minimum
Requirement for the Rainiest year •.••••.•.••..•.... 83
A. 1 .
Monthly Average Nutrient Requirements for Cobra
Zebu Cows in Dahra, Senegal:
Age = 2 Years .••.••.. 9G
A.2.
Monthly Ave~age Nutrient Requirements for Cobra
Zebu Cows in Dahrc, Senegal:
Age = 3 Years ..•..... 97
A. 3.
Monthly Average Nutrient Requirements for Cobra
Zebu Cows in Dahra, Senegal:
Age = 4 Years .••.•... 98
A. 4 •
Monthly Average Nutrient Requirements for Cobra
Zebu Cows in Dahra, Senegal:
Age = 5 Ye2rs •....•.. 99
A. 5 .
~onthly Average NutriEn~ Requirements for Cobra
Zebu Cows in Dahra, Senegal:
Age = 6 Years •...... 100
A.G.
Monthly Average Nutrient Requirements for Cobra
Zebu Cows in Dahra, Senegal:
Age = 7 Years
101
A.7.
Monthly Average Nutrient Requirements for Cobra
Zebu Cows in Dahra, Senegal:
Age = 8-10 Years .••.• 102
A• U•
Monthly AveraGe Nutrient RequirEm~nts for Cobra
Zebu Cows in Dahra, Senegal:
Age ~ 11-12 Years ... 103
Monthly Average Nutrien~ Requirem~nts for Cobra
Zebu Cows in Dahra, Senegal:
Age = >12 Years .•.•. 104
B. 1 •
Optimal Solution of Supplemental Feeding 100-Cow
Herd During An Average Production Year - System I
(1007~ OF REQUIREr"ENTS ARE (·1ET)
106
B. 2.
Optimal Solution of Supplemental Feeding 100-Cow
Herd During An Average Production Ye2r -
System 11 (95% OF REQUIREMENTS ARE MET) .•.......•. 107
Optimal Solution of Supplemental feeding 100-Co~
Herd During An Average Production Year - System
1 I I
(90% OF REQUIRE1·1ENTS ARE [·lET) •••••••••..•.•••• 1 08
vii

---

8 . 4 .
0 P tilT. a 1 Sol uti 0 n 0 i
Sup pIe men tal Fe t: din g 1 (; C- C0 \\./
fie r d [; u r in g An J\\ v era g e Pro due t ion Yea r -
System IV (85% OF REQUIREMENTS ARE ~ET)
109
B.7.
Optimal Solution of Supplemental Feeding 100-Cow
Herd During The Rainiest Production Year - System
I With 30 Percent Increase in Forage Quality •.••... 112
B.8.
Optimal Solution of Supplemental Feeding 100-Cow
herd During The Rainiest Production Year - System
11 With 20 Percent Increase in Forage Quality ....• 113
8.9.
Optimal Solution of Supplemental Feeding 100-Cow
Herd During the Rainiest Production Year - System
11 With 30 Percent Increase in Forage Quality •..•. 114
8.10. Optimal Solution of Supplemental Feeding 100-Cow
Herd During the Rainiest Production Year - System
III With 20 Percent Increase in Forage QL:ality .... 115
8.11. Optimal Solution of Supplemental Feeding 100-Cow
Herd During The Rainiest Production Year - System
III With 30 Percent Increase in Forage Quality .... 11G
B.12. Optimal Solution of Supplemental Feeding 100-Cow
Herd Duri~g 'The Rainiest Production Year - System
IV Wi th 20 Percent Increase in' Forage Quali ty ..••. 117
8.13. Optimal Solution of Supplemental Feeding 100-Cow
Herd During The Rainiest Production Year - System
IV With 30 Percent Increase in Forage Quality ..... 118
8.14. Optimal Solution of Supplemental Feeding 100-Cow
Herd During The Driest Production Year - System
11 With 20 Percent Decrease in Forage Quality ..... 119
8.15. Optimal Solution of Supplemental Feeding 100-Cow
Herd During The Driest Production Year - Sys~em
III With 20 Percent Decrease in rorage Quality .... 120
8.16. Optimal Solution of Supplemental Feeding 100-Cow
Herd During The Driest Production Year - System
I V \\v'i t h 20 Per c en t
De c rea se in f·· 0 r a [; e Qua 1 i t Y• . • . • 121
viii
.+c

---

LIST OF' FIGURES
Figure
Page
1.1
Map of Republic of Senegal •••...•...•............... 5
1.2
Agricultural Production Zones of Sen~gal ••.......••. 9
2.1
Approximate Dietary Energy Partition by Cattle
at Maintenance Intake •••••.•••••••••.•••••.•..•...• 34
ix

---

Atstr2ct of T~esis Presented ~o the Creduat0 ~chGol
01' the
University of Florid8 in Partial F'ultillffient
of the Requirements. for the Degree of ~ast=r of Science
c;Cot!O~lIC A1'~ALYSIS OF F£EDrr~C
COBRA ZEEU CATTLE IU DAHI-:A,
SH1ECAL
Dy
Kodjo Pierre Abassa
Chairman:
hilliam C. Boggess
ro/ajor Departrr.ent:
Food and Resource Economics
Cow-calf production in Dahra faces numerous problems,
most of which are common to sahel zones and to developinG
countries.
Low annual
rainf8lls and lonE dry se2sons,
severe
feed resource liffiitations, variations in quality dnG
quantity of the rainfed pastures,
lack of informa~ion (data)
on these varia~ions which occur within anc between years,
lack of knowledge of specific nutrient requiremen~s of local
a~imcl breeds, end high supplementel feed costs are some of
the problems.
~he ~ajcr purpose3 o~ this study were
to de~ermine the
nutrient requir2ments of Cobra Zebu cows under their
specific environmen~ and to provide guidelines as to how to
combine economically the range and supplemen~2l feec
resourCES ond still satisfy the cow herd nutriect requir9-
ments curing the dry SE2son.
A nUT.rie!1t r-::-::uirer..e:r.t {.,oael
I,! hie i~
,~ c c c u n t s
f G r
~ r: e p n y s :. 0 1c g i c 3 1 2. r. .j ~ p '" c i L .. C e :1 vir C' n -
rr e r. t
C 2 r~ (~i t i 0 ~ E
C l'
t ri Eo' 2. n ).. IT: ;:.d.s H (] S t..: ~ t: d :d 0 n c
\\d t. n c:;
1 i n eCl r
x
,~..

---

programming model designed to determine optimum feeding
strategies.
The cost minimizing solutions showed substantial
decreases in feed costs per kg of ca~f weaned as the manager
chose to meet only fractions of the minimum requirements.
During any production year (i.e., the average, rainiest or
driest year) and for any management system (i.e., system
where 100, 95, 90 or 85 percent of nutrient requirements
were met), feeding costs would be expected to increase from
the first period (January-April) to the third period (July).
The optimal carrying capacities of the rangeland were
estimated at 300.33, 145.70 and 433.13 hectares per 100-~ow
herd during the average, rainiest and driest years,
respectively.
Phosphorus and digestible protein were the
most limiting nutrients in the pastures from January through
June and July, respectively.
The least-cost supplemental feeding program called for
brewer's dried grains, groundnut meal, cottonseeds, urea,
sorghum straws and Gane molasses.
Feeding of nutrients with
high concentrations of both protein and energy usually
occurred in July.
Chairman
. . \\'1
".1 \\..
xi

---

CHAPTER I
INTRODUCTION
The Problem
Agriculture is the mainstay of Senegal's economy.
It
directly accounted for 47 percent of the total merchandise
exports in 1979, 29 percent of gross domestic product (COP)
and 76 percent of the total labor force in 1980 (Table
1.1).
Ironically, the country's foreign trade accounts are
heavily dominated by food i~ports, a continual strain to the
chronically ill economy.
The development indicators (Table
1 • 'i)
revea 1
.
a population annual growth rate of 2.7 percent when
the annual CNP per capita growth rate was -.3
percent for 1ge1 with an annual per capita
agricultural production growth rate of -1.~,
an increasingly negative trade balance which was
-$159 million in 1975, -$250 million in 1977 and
-$333 million in 1978,
food imports (as percent of total agricultural
imports) of 87.5 percent in 1979,
a government deficit of $30 million for 1980,
2
slow beef cattle production growth rate of .Y5
percent in 1979, and
1

---

")
c..
Table 1.1.
SElected Development Indicators
Po pu lrJ t i on
rh d - 1980 (T h0 usa ncs) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 , GG1
Annual average growth rate (1982) .•••••..•.•• 2.7 ~rcent
Gross National Product (GNP)
1900 ($ millions) . . . . . . . . . . . • • • . . . . . • . . . • . . . . . . . . . 2555.1
Per capita (S, 1980)
451.3
Aver~ge annual growth rate (1960-1981) •••.••• -.3 percent
Agriculture
Average annual per capita growth rate
(19·70-81)
_
-1.5 percent
Agriculture production as % of GNP (1980) .•••• 29 percent
Proportion of labor force in agriculture
(1 S80) •••.••••••••.••••••.••••••••••••••••••• • 76 percent
Foreign Trade .'
Trate balance ($ millions)
(1976) •••••••••••.•.•••••.••••••••••••••••••••••••• -~1 59
( 1 977 ) . ~
- $ 2 50
(1978)
·
-$333
External public debt as % of GNP (1980) •.••. 34.~ percent
Agriculture exports as % of total
merchandise exports (1979) •.••••.•.••..••••....••••• 47.1
Food imports (1000 metric tons, 1<;182-83) .....•.....•• 3<)5
Food Aid Needs (1000 metric tons, 1982-83) ••.•••.•..•••••• 93
Fir.ances
TOL-al domestic revenUE: ($ millions, 1980) .•.••••••••• 570
Total expenditures ($ millions, 1980) ••••••••••.••..• 583
Deficit ($ millions, 1(80)
13
Sources:
World Bank (1983);
USAID (19b3)

---

3
2
total meat deficit of 20,000 to 27,000 metric
~ons for 198C-82 (Hongodin and Tacher, 1979).
Obviously, there are numerous reasons for these sorry
economic conditions,
i~cluding natural,
socioeconomic and
political factors.
However, within the agricultural sector,
there are plausible technical causes of the sluggish growth
of the livestock industry, particularly the beef cattle
enterprise.
The latter is a vital component of the live-
stock operation since it provides 70-80 percent of domestic
meat supply.
Unfortunately, it is also the most com~only
affected in terms of meat deficit.
The annual beef deficit
was estimated to be between 40 and 60 percent (Faye, 1geO).
Most beef cattle found in Senegal are raised in the
sub-arid, sylvo-pastoral zone relying almost exclusively on
the natural pastures for their feed supply.
Unfortunately,
these pastures grow only during the three to six month vet
season of the year, are generally limited in quality and
quantity, and represent the total available feedstuff for
the remaining nine to ten months.
There is little or no
practice of supplemental feeding.
Animals, therefore, f3ce
a long cry season which causes them to undergo ttemendous
weight losses and consequently a decrease in total produc-
tivity.
Most of the by-products available for supplemental
feeding purposes are exported.
In 1977, Senegal exported 31
percent of the groundnut meal world market share, which
represented 9-10 percent of the total merchandise exports
;

---

4
and nearly 99 percent of the total groundnut meel producec
in the country.
The
palmnut meal produced in Casamance is
entirely exported to West Germany.
The process, blessed by
the government because of the export tax revenue and the
poor trade balance,
results in much higher export prices
thQn domestic cattle producers can afford.
Supplementation, when used, is technically questionable
and economically unsound.
The growth patterns and thus the
nutrient reqUirements of the native Zebu cattle are not well
understood for their specific environment.
More impor-
tantly, there are no guidelines as to how to combine the
feed resources economically and still satisfy the nutrient
requirements during the dry season.
Senegal:
Location, Topography,
Climate and DemographY
The Republic of Senegal is a coastal country which lies
on the westernmbst part of the African continent.
It
occupies an area of 196,722 km 2 and is bounded on the north
by Mauritania, on the south by Guinea and Guinea-Bissau, on
the east by Mali, and Oh the west by the Atlantic Ocean.
Gambia, a tiny independent state, extends into Sene£al for
350 km alone both sides of the Gambia River (Fig. 1.1).
The
capital city of Senegal is Dakar.
The country is made up mostly of flat savanna plains.
The natural vegetation varies from semi-arid savanna in the
north to grassy Sudan savanna in the central zone, to
forested guinea savanna in the south.

---

"
~~~~PP~/&&~Z0~
a...-_.4 -.-..
l..--=-:=:
:~f~:::
:::~~.:~:::::::~
:
:::.:::::~:~:::::-
Mbour
~ _~~::---:~:. /0
.....
......... _-_...
.
_~----
Vi
~"1:.
~t(,
-e
"'.\\ ( SENEGAL ORIENTAL REGION
Vellngara
\\
\\
\\ °
Sedhlou K~lda
.
\\
...-.,,-~
~. --~ - ~ -.eyn~ _..l.._~
~//fi'/////////////N////////////////-
.. -._~
~
'T7.
GUINEA BISSAU ~
' , ' / / / / / / /
FiE;lIre 1.10
(Jap of kepubl ic of ~ene[,al

---

.. ,
...i....'
6
The climate is characterized by two seasons (rainy
season and dry season).
Depending on the latitude, the
duration of the rainy season varies from three to six
months.
The average temperature ranges from 18 0 C to i1 0 C
and the annual rainfall from 400 mm to 1800 mm.
The human population was estimated at 5.5 million in
1979 with a growth rate of 2.8 pe~cent pe~ year.
The
average population density is 25 persons per km 2 with
extremes of 5 persons per km 2 in the Eastern Senegal and
1,540 persons per km 2 in the Cap Ve~t region.
The main
ethnic groups are the Wolof, the Serer, the Fulani, the
Toucouleur, the Oiola and the Mandinka.
Each group is found
i~ a specific region except the Fulani,who are scattered
throughout the major livestock-raising area of the country.
Administratively, Sengal is divided into six regions,
namely the Oiourbel/Lou[a, the Sine-Saloum, the Casamance,
the Sengal Oriental,
the Fleuve and the Cap Vert ~egion
(Fig. 1.1).
CroD Production
eo
Crop production is the major enterprise of the primary
sector of Senegal.
The leading crops produded both in terms
of value produced and metric tons harvested in 1980 are
groundnuts ($40,810 million and 530,000 met~ic tons)
followed by millet ($35,S45 millions and 553,OCO metric
tons) (Table 1.2).
Nearly 90 percent of the existing cropland is found in
Groundnut Basin (75 percent) and Casamance (13 percen~).

---

7
Table 1.2.
Selected Agricultural Products:
Quantity and
Value-Added, 1950.
Ounntity Produced
Cornmod i ty
(Million r-JetI' ic Tons)
(r'1i 11 ion $)
Cassava
.120
5.880
Carn
.049
2.597
Cotton
.008
1.984
Cotton seed
.014
.350
Cow pea
.013
.923
Groundnuts
.530
40.e10
Heat
.038
18.278
rH 1 k
.093
9.'165
r,~ ill et
.553
35.945
Rice
.068
5.440
Sweet potatoes
.200
1 .400
Sugar
.035
2.975
Vegetables
.084
6.132
Source:
vio r Id Bank ( 1983)

---

The Groundnut Basin itself is made up of three sub-regions
(Fig. 1.2).
~hose are
(1)
the ~orthern Groundnut Basin including Louga and
the northern half of Diourbel
(2)
the Central Groundnut Basin including Thies,
Southern Diourbel and Northern Sine-Saloum
(3)
the Southern Groundnut Basin including most of
Sine-Saloum.
The overall crop distribution is shown in table 1.3.
The most densely populated and densely cultivated area of
Senegal is the Central Groundnut Basin.
The Ferlo or sylvo-
pastoral zone, described later, is devoted to raising
livestock and the Cap Vert, coastal district, to fishing and
commercial veg~table production.
Livestock Production
Livestock contributed 19 percent of value added by the
agricultural sector in 1975.
It supplies draft power for
farms,
hides for tanning and export, meat, and limited
amounts of milk for domestic consumption.
Table 1.4 lists
annual inventories by species for years 1970 through 1979.
Cattle are the dominant species of the livestock
industry and are distributed as shown on the map (Fig.
1 .2) .
They are found in
(1)
the Ferlo or sylvo-pastoral zone, a semi-arid
region, best suited to extensive livestock grazin[.
and acacia gum cultivation;
the Ferlo includes the
southern part of the Fleuve region and extends

---

KEY;
IV\\VRITAHIA ~.~
~-----------~-~~- --------...", "
Rico Development
--
,
--------/
nEUV£
~, •
ProJcct~
SU!lJr
ATLAII TIC
'~
Ilortilcrn L Imf t
of Tsct3C fly
OCEAIl
~~
,. ....
--
'-.
.
,
,
' ...
b>F
,
I
,
t P' (Northern) .
(
C'
,
HRLO
1].
.I
C
. - -
-
-
-
-
-
,
V I
I
GROUNDNUT
"
(Ccntrlll) .
\\
CII tt I c
D!lSIH
IIflLI
- -
t?7s0~hcr"O) \\ -
....~ ..
---
- '''..................-
..........
Cottle
,,•I
I
GIJIIIC:/I-O/SSAU
GUll/EA
N
\\0/'"
j
__ - - . _ _ _
I
F i ! 1I r' (
'j.:.
/'..i. l' .i. (: U j 1. 1I r': ,
•
.
j'
[. L l. l J r' 1 ] (",[,
C'r
I'.
d
~.'
Cl j
. { • n t
i';;

---

';"[, lJ 1e 1. ).
ke£ioncd
l)i.stcillution 01 Ilgricul tun:! ProulIct5
'1
Northern
Central
Sou the c'n
Groundnuts
Grouncnuts
er ounanU1:S
~0nercl
r~'
r,Cj sin
Basin
Basin
CasC1rnance
Or ienta 1
Fleuve
Cct p Ve [' t
~'e r 1 0
CO\\,:pea
Cm. pea
Cotton
Sorghum
~~illet
t,ji 11 et
~) f; 0 r t - eye 1e
t:illct
Tobacco
Latf:-sc:ason
Cotton
IlD i Z le
1: i lIE: t
rH lIe 1:
C:i::ssaV2
C;::ssC'\\VC:.
/;aiz€
Uplunci Hiee
ti3 ize
IUc0
CO[iHnerci2.1
Cl ttll:
Ve g e tD b 1 e.s
--"
Groundnuts
Croundnuts
1\\1 i l l e t
S'rIampland-
Ground-
Sorghum
c
l\\ iCE:
nuts
Ground-
Cotton
~ugac
nuts
C',lne
(,;aizE:
Tomatoe5
&.
He ct
Pe ppc ('
....~::?;" ..,
/~~:~
Cattle
Hive ['
( I> \\ ",
Fish
"?' \\
J.~
'~!
",Ol;1r("', 'J1
Ctl >1<
.
"",>;L~//;~d~'1 ,'tlC! L 0",P2 r.y (1 'J"0) .
.7
t:'l/r.
, ~:-~':..,-'

---

'1'.3 b 1e
1. '1 •
Li v e s 1: 0 c k Pro d u c t ion i n ~ e n e g c) 1 i nTh 0 uSe n d s 0 f
fin i mCl 1 s :
1n v Ent 0 r i <:' S 1'r 0 III
1~70 Through 19'11j
1970
1')'11
19'(2
1e)'( j
. 1974
1975
19'(6
19'("(
19'1 I.!
'j S'/9
Cattle
2,b15
2,<)54
2,250
2,250
2,)1tl
2,380
2,240
2,514
2,S3j
2,55/
.sheep
1,060
1,929
1 , '(90
1 ,62'(
1,7(JO
1,70b
1 ,7'14
1 , trl3
1,281
1 , <)14
G02tS
ll"JO
U75
900
c;13
I~ 50
Li53
Llt..J'I
9j8
940
CY)b
~wine
1C?
1'15
182
1 tl9
196
160
1G6
323
1'I j
1'/6
Horses
199
20~
20'(
200
204
~10
2HJ
22S.j
240
245
CEimels
'(
'(
5
6
()
6
6
6.90
'7
'(
A~scs
185
190
186
186
190
19u
--"
200
210.2
230
250
- '
Poultry
5,000
5,300
5,500
5,600
6,200
6,72
6,800
8,200
'I , 497
7,S4?
:..Jource:
D.':">.P.f\\.
(Direction dc la ':";ante et des Productions Anim81e) Cit.
F<:tye
(1900)

---

12
beyond the Senegal River to the northeastern edge
of the Groundnut Easin,
(2)
part of Seneeal Orien~al beyond the northern
reaches of the tsetse fly zone and
(j)
easternmost part of Casamance infested by the
tsetse fly.
Ndama cattle,
trypano-tolerant 80S taurus, are raised
in Casamance and Zebu cattle, Bos indicus, are found in the
Ferlo and part of Senegal Oriental.
The Zebubreeds include
Gobra Zebu, Maure Zebu and Guzerat Zebu.
There is also some
production of Djakore cattle, a crossbred 80S inducus x 80S
taurus,
in the Southern Groundnut Basin.
With the exception of Guzerat Zebu, which is raised in
a government research station as a dual purpose breed (meat
and milk), all .~hese cattle are be~f animals.
The beef cattle enterprise has long been managed by the
Fuldni
traditionally nomadic herders, known for their
1
expertise in animal husbnndry.
These herders range
t h r 0 ug h0 Ut
the \\J est Af r i ca .
The he r d m0 vem e n t
follow s a
seasonal pattern dictated by the availability of natural
grazinglands and water which are in turn controlled by
rainfall distributions.
Today,
the herders need not cover
hundreds of kilometers to graze and water the animals.
Their movement is now reduced to a few dozen kilometers as a
result of the drilling of wells in areas where cattle are
f,razed.

---

13
Three major livestock production systems are currently
i'ounc in Senegd 1.
ThesE: are
(1)
the nomadic/semi-noffiddic herding system,
(2)
the traditional stockreising system where cattle
graze on unclosed land,
(3)
the freehold farming system with fenced ranching.
The nomadic.herding is specific to the sylvo-pastoral
zone;
the other two, however, are found in all three areas,
i.e.,
the ferlo, Senegal Oriental, and Casamance.
The integration of livestock and crop production
systems is practiced with the production of Djakore cattle
in the Southern Groundnut Basin.
This is intermediate
between the tsetse fly free zone (Ferlo) and the tsetse fly
infested zone (Casamance).
The dairy:industry is a minor enterprise in Senegal
despite the govern~ent's ~fforts to reduce or eliminate the
country's dependence on imports of milk and other dairy
products.
The problems faced are common to most tropical
areas, namely the low genetic potential of the local breeds
for milk production,
the high costs of research related to
this field,
and the risks of importing high milk-producine
exotic breeds not adapted to the environment.
The research
on Guzerat breed at the Oahra Research Station is quite
promisine,
whereas the economic impact of accomodating
imported Mombeliarde breed in Sangalkam needs to be
investigated.

---

14
Agricultural and Industrial Contribution
·to Livestock Production
Senegal is suffering a long-term deficit in cereal
grains for hUQan consumption.
As a result, there is no
grain for animal feeding.
The agricultural sector provides,
however,
substantial amounts of by-proaucts which can
ultimately be u~ed to feed livestock.
The estimated agro-
industrial by-products production in 1978 was 5,577,850
metric tons (Mongodin and Tacher, 1979).
Among these by-products, groundnut meal, and cereel and
legume straws represent major feedstuffs.
Senegal produces
top quality groundnut meal and large amounts of cereal-
legume straws in most of the administrative regions.
The
available straw for feeding adult ruminants in 1981-82 was
estimated at 3550 to }700 millions of UF 1 which represent
more than six times the total energy supplied by g~ains
prod~ced in Senegal, an equivalent of 3.6 to 3.7 million
rr.etric tons of corn feed to ruminants Ulongodin and Tacher,
1979).
The estimated available supplies of by-products for
1SB1-82 are shown in table 1.5.
Description of the Study Area
The area considered in this study is Dahra, a
government livestock research station,
located 267 km from
the nation's capital COakar) and at 15.300 North latitude
1
French energy unit (Unite fourragere Leroy)

---

'12clc
I.:).
('uantity
(mc1.Tic tons)1 ot ilgricul1:u['~tl .::Jne] lnaustrial t:y-pt'OCUC1..::i Ilve-dlable
1'01'
the :..>upplerrlental !-<ations by f\\t'p,ions
He{"ions
Diourbel-
East-
::';ine-
by-products
Cap Vert
Casamance
Louga
Io'leuve
Senegal
~a lourn
'1'hi es
fh lIe t
b r 8 n
2,500
\\~'heat bran
?,500
\\': h eat mid d s
8,800
Ere 'vI e r I s d r i e d
f;r::Jins
9GO
Eice bran
200
1 ,OCJCJ
200
Idce midds
800
),000
80O
(cone molusses
1r( , 500
Sorghum &
millet straw
G,OOO
bj~,OCJO
1,20'/,UOO
210,000
411,000
1 , '( 4 :; ,000
SeO,O()(i
-"
Idce straw
100
20G,000
114,000
40,2000
3,500
'(GG
\\...T
Groundnut
straw
1 ,800
216,500
484,400
5,100
90,300
U'!':3 , DOO
221,200
Cow pea straw
200
),000
'1G,800
1 '( , 000
38',400
Groundnut meal
1jO,OOO
2'1,000
84,000
'11 5 ,OOC)
Cotton seed
meal
'f ,10O
'(,100
Cotton seeds
17,0()0
12,000
L,OOO
Cotton seed
hulls
6,300
0,300
Palmnut meal
),100
Groundnut
hull s
? , 40O
3,400
7,500
jOU
1 t),jUO
12,bOO
Source:
Nongodin & Tacher (10'/'9)
1
Projection 10r 1901-i32

---

16
and 15.300 West longitude, in the Sylvo-pastoral zone.
The
station occupies an area of 6200 hectares.
The climate is typically sahelian with about 9 months
of dry season and 3 months of rainy season.
The wet season
begins in mid-July and ends in October.
August and
September are the rainiest months,
recording more than 62
percent of the average annual rainfall of 492 mm.
Hainfall
varies significantly between years and sometimes within
years.
The annual average temperature and humidity are 2S oC
and 49 percent, respectively.
The soils are poor in minerals and the plant nutrient
particularly in nitrogen.
They are either brown-ocher, sub-
arid, very sandy and very permeable soils or ~ropical
ferruginous soils with low to poor drainage •
.
~he vegetation is Qade up of Acacia sp. and natural
pastures characterized by annual grasses and legumes.
This
vegetation is deeply influenced by the annual rcinfalls and
may partially change over years.
As a result, the rainfed
pastures available to animal consumption are subject to
between and within year variations in quality and quan-
tity.
The grass and legume species grow and ma~ure fast
after the onset of the rainy season, dry out at the early
stage of the dry season, leaving nothing but small amounts
of poor quality straw.
Objectives of the Gtudy
In beef cow calf production,
two major factors affect
productivity arid net profit.
These are genetics and

---

,,,.
~
-
1 7
environ~ent (and the interaction between the ~wo).
There
ccn be no gentic improvement \\/ithout first improving thE:
environm~nt
~hich is composed of health, nutri~ion, climate
and management.
ProdUCers are as much concerned with the
m2no[emer.t and uutrition of their bulls 2S of their cows.
However,
the nu~ber of bulls represents only 3.3 to 4
perce~L of the total cattle number ~r.en natural breeding is
~~2cticed;
consequen~ly, the manager will spend more time
and money managing and feeding the cows than the bulls.
The
expected number of calves born, weaned and sold every year,
under everage climetic conditions, depends primarily on the
number,
the feeding and management of the cows.
In the
ferlo zone of Senegal,
th2 nutritional status and the
performances of beef cows decline from low to very poor as
the 7 to 9 month dry season proceeds.
To :mprove these
performances, one must properly feed the animals,
i.e.,
be
able to determine
tr.~ir specific nutrient requirements,
inventcry the natural forage resources at the end of the
rRiny season and determine the optimum feeding strategy.
This study intends to determine the nutrient requirements
for Cobra Zebu and to show how least cost analytical
tAchniques can be used to economically supplement the
natural grazing land using the agro-industri21 by-products.
ihe specific objectives are to
1.
use the growth curve of Cobra Zebu under the
specific conditions of Dahra Research Center to

---

1 b
determine the nutrien1: requirements of the Cobra
cow herd Gnd
2.
utilize least cost analysis to determine the
optimum feeding s~rategies for Cobra Zebu cows.
Plan of Presentation
The next chapter reviews the economic theory of the
fir~, lineer programming procedures, and the biology of beef
cattle growth and nutrition.
Chapter III develops the
specific economic and biological models used in this
study.
The data anG the results are presented in Chapter IV
and V,
respectively.
Finally, Chapter VI summarizes and
concludes the study.

---

CiiAP'l't:1t
Il
LCCJ1,:cr: I C Ar< C i2 I (; LOG I Ci\\L FR;'diUW El,
~conomic Consider2~ions
L~iorc examining difl~rent econcmic conSiGer3tions,
a
fEW
technical definitions need to be kept in mine.
l' h to r e e xis t .3 2. n e con 0 mic .fl rob 1e IT: "~J!; e r. per son ~ wr. 0 Cl r e
seeking to maximize some goal have limited resources and
must cheose between alternetive courses of C;Cl:';:'or"
(Bishop
and Tcussaint,
195[.,
p.
2j).
A goods or service
is SCdrce
~ive
1_
Ut=!
some
amount of one thin& to ge~ some of 2nOl:ner goods or scrvic0
(CramL'r 3nd Jensen, 1S·J2,
p. ~) or simply wht::rl iL: exisl:s in
li!T,itec amounts.
t: con 0 mic s i s a s 0 2 i 2. 1 s c ::. G r. c e \\. r. i chi s cor. c ern '2 d \\00' i t (;
overco~ing
the effects of sC2rcity by improving the efii-
ciency ~ith whic~: scare resources are allocated ~mon£ their
m2ny co~peting uses so as to best satisfy hum~n ~ants.
As
fer 2fricult~r2l economics,
it i~ an appliea social science
cie3line;: ',.;ith ho\\-; mJnkind chooses to use 'technical knowledge
2nd SC2rce productive resources such as land,
labor, capit2l
and management to produce food and fiter and to distribute
it for consumption to various members of society over time
(Crar.Jer and Jensen, 1(.j82, p. 6-'1).

---

20
A production process is a physical event in which an
input vector is transformed into an output vector
(Dorfman,
1S'S1) or si~ply an event whereby some goods and services
(inputs) ere transformed into o~her goods and serviceE .
(outpu"ts).
A production function
is a mathematical relationship
describing the way in which the quantity of a particular
product depends upon ~he quanti~ies of particul~r inputs
used
(Bishop and Toussaint, 1958).
t. firm
is "d decision making unit or managerial unit of
production"
(Dishop and Toussaint,
1958) or in other "lords a
"technical unit that uses economic inputs to produce outputs
of goods and services which are sold :to households or other
firms.
A farm is a particular firm which combines resources
in ~he production of agricultural products.
The economic analysis conducted in Chapter V is per-
formed within the framework of the theory of the firm
assuming the latter is a price taker in both product and
fC)ctor markets.
Two of the critical decisions faced by the firm are how
much to produce and how much 01 various inputs to use to
produce an output of interest given the prices of the inputs
and outputs and the production function.
In order to answer
,/~~;~~~:~~
these questions,
the ferm firm m2nagerh~~/'ed,s-to"h<j\\~ a gocd
~
" .~~\\
underst2ndinE; of the physic21 and biO~b.'.-~lical\\\\J\\PToc\\~ises.
"~~'D..\\~/~
, J
~
_
'~.J
,Qj
"
.:;,Q
0<;"
,'_~ .",,'-5,
.:....:...'_. ,. ('.~..

---

21
The following sections develop the ~heory of the firm
and its oecision rHcddng process and present U;2 biologica 1
backfround of the firm of interest.
Theory of the F'irrr. 1
The basic assumption of the neoclassical theory of the
firm is that the firm's objective is to maximize profits
given ~he production function,
input and output prices.
The
firm has to make three types of decisions:
technical deci-
sions concerning the methods of production to be used,
quan-
tity decisions,
i.e.,
the amount of goods and services to be
produced and marketing decisions regarding where and how to
med/et the products (Dorfr.:an, 1951).
r-:arketing decisions
are not addressed in this study.
Technical decisions are !.'lade by biologists ana,
tl1ere-
fore,
is acove the scope of economics which assu~e 2 priori
a technically efficient production function.
10 the econo-
mists, output of one good cannot be increased without
increasing input(s) or reducing output of another gOOd in
cases where more than one good are produced by the firm.
The production function is assumed to be real and differ-
entiablE.
To be a differentiable production function,
the
marginal rates of substitution has to be well-defined with
respect to <:lny techniccdly efficient vector (I.ialinvc:wd,
1
Reierences:
8rems (1967),
Henderson and Quandt (1971),
lntrilieator (1971), Halinvaud (1973),
Hicks (1974),
~amuelson (1974), F'erguson (1975) and Angirc:sa (1979).

---

19jj)
and the function has to be continuous,
defined over
the do~ain of non-negative inputs anc outputs.
1he quantity decision has ~o do wi~h the selection of
the optimal level of output and the technicelly efficiept
set of inputs whicl: produces that level of output.
To make
these decisions,
the firm can use either the production
function approach (input side) or the cost function approach
(output side).
Marginal Analysis Approach 1
Input side.
The firm faces the problem of selecting
the level of output which maximizes its profit.
Given that
the firm is free to choose any input vector in input space
and the product price is exogeneousl~ known,
the problem can
be expressed mathema~ic3lly as follows.
Assu~e a multiproduct and multifactor production
function,
F(y,x) = F(y
y
y
l '
2 ...
rn'
where
Yi.
= output vector, i = 1,2,3, •.. m
X
input vector,
j
= 1, 2,
3,
... n
j
er.d
1
The section draws he2vily on I-ienderson and Quandt (1971)
and Intriligator (1971).

---

' ) ','
L
of
- - < C,
ay i -
~ > (!,
ox"o
rr,
r.
iT(y,x)
= py - rx = LPiYi - [r ,x '
J
J
i=1
j=1
s.t.
F(y,x)
> C
P
0L~PCt
pric~,
r = input price.
l[,c
profi ~ fi12ximUiI, cen th2!l
Le
f'cnnul2.tec c.S
Max iT(y,x) = py - rx + A(F[y,x])
2ssu~ing x>0,
ar9
on
-~
p,
c·
=
().
fer
i=1,
aY,
+
AF
,
... ,
r~.
1
1
1
6Yi
J
OiT
-r '
of
+
AF~
C;
F"
=
for
~=1
n.
=
, . . . ,
ox
J
,I
d
ox .
t]
J
OTT
F(y,x)
= l'.
oA
;c:)
for
any r::;ir of triE' firsT m equations,

---

211
p.
1:'.
1
=
1
=
i
t
k
Pk
F\\
i.e.,
the 1'2te of product transformation between
two products ~ith all otner inputs and outputs held
constant, must be equal to the ratio of their
prices,
b)
for any two of the second set of n equations,
j
t
k,
i.e., each input is used to the point at which its
price is equal to the value of its marginal
product.
The second order conditions require that the bordered
Hessian matrix be negative definite,
i.e.,
the production
function is strictly concave and that the law of diminishing
returns holds.
~e can now solve the (m + n + 1) first order conditions
to obtain optimal input levels as functions of Lhe (m + 1)
parameters assuming that the second order conditions are
satisfied.
x .*
j =1 ,
••• ,
n
J
The n equations are called input demand functions.
They are
homoceneous of degree zero in p (product price) and r (input
costs) since the first order conditions are not changed by
sC21ing product price and input costs.

---

Gctput can be obtainet 2S a function of output pric~
;: rh'
~; roe Uc -;:: i 0 r: 1 u n c 7. ion
V'"
(l:*lr·,rj)
Yi *
(
\\
p,r;.
- 1
Tr;is is "the output suoplv function Hhich is olso homofeneous
of tefr~€ zero in p iln( r.
Given the followin~ threE equatiens whicr
2re respEctively the implicit production function,
t~e cost
~cu:::...i()(l 2r:d
the
exr:2nsior: pa-;:'h
[
(
)
U
r'
Yi'
Y2'
•.. ,
Ytn'
x1'
x2'
••• ,
xn
==
,
n
C
I fjXj + b,
j = 1
Eo
(y"
x ..)
==
u,
i
1,2,
.•.•
rn,
J
= 1 , 2 ,
•.. ,
n .
..:..
..)
Cost C2n be obtainet as a function of output.
"The
expansion path [lVeS the inputs t~2t maximize eU1:put at ~ny
particular level of cost or,
equivalently,
the inputs "that
minimize cost at er.y particular level of cutpu~, with the
level of cost indicated by the isocost and the level of
output indic3teG by the isoc;uantl!
(Ir,trili[':ator,
1971,
p.
1 r ~. )
J>
•
'jTE:'
re8der i:.: r,.=:ferrr~·c
to Grerr,s (1'::07) er ht:t:dcrson ar:d
0uantt (1S'l1) for details regafdin~ the derivation of the
C8S-;:' function.
IJoticc t1:2"t the form cl' tr.e COSt function is
indicated by t~e perfectly competitive firm's production

---

.,.
::,'
26
function and that the cost function is derived assuming thaL
the firm operates on its expansion path.
Without the latter
assumption,
the cost minimizing input levels cannot be
determined.
The profi~ function can now be written given the
production function and the cost function c(y)
+
b as
IT = Tr - Tc
IT = p.y -
(C[y]
+ b)
where
y = output vector
p = output price vector
Max n(y)
= p.y - C(y) -b:
The first order condition for profit maximiza~ion
requires that,
o for all i
or
= MC·1
This ccnditior. indicates th2t the firm should Expano its
output to the point at which its marginal revenue (which i~
a constar.t p under perfect competition) equals m8rfinul
cost.

---

The
SeC onc
order condition for
profit r:J<.lxi;;:izinc
< G
r •. 2
U J
.
1
or
< c
'i'1"'. i s
i r:~ p l i 2 S t h;;,"t m2 r gin 2 1 cos t o ; C) mu 5 t
be
:i. n er;:: El sin €
2 1:
U:e
point of maxirr.um proi'it other\\:ise "the equality of i:R
cHi G rT
\\: 0 u 1d g i v e
2
Pc· i n t
c f
m i n i m u m r: r 0 f i 't "
(h (' n de:, son .3 t"'i C
Quanct,
1971,
p.
73).
i 1.::! t h (~ ~ 2 t :. c e' 1 El r C f r Cl r,j r" i r: i'
J\\ 0 P r C :J C h
Linear pro~r~~minf (LP) model.
Line2r progrnmmit"'ig can
be defined ~s a technique for determining tr.e optimal use
",
o..!.
resources (expressed 2S 2
set 01 constraints)
~(0n many
alternative production processes exist.
It,
c:herefore,
dill'ers from optimizC'ltion uncer
the mc:q~:inl)l 3nL,lysis in
tr.ree y;::lYs:
"first,
it deals \\dth optimiz3tion in the
lorsi:'
r2~hEr t~3n in
the sm~ll;
second,
it deals Hi,'U: rE!strictiv'2
inEcucli~ies rather th2n' with restrictive ec;uCllities;
third,
i:- deEds wi th line.:, restric-i:ions r2thc:r thc:~n h'i th
restr<1ints of ~ore ger.erel form"
(Dorfmen,
1~)1, p. 12).
~or a LP proble~
to exist,
three ccmpo~ents 2r~
simultaneously reouirec.
These are an objective function,
" ..
.. ,:t:. ,.
.J. •••

---

213
objective 2nd resources or ether constrain~s.
In LP,
eE:ch
r0~re~ontec 2S an activity or
s~t of E:ctivitics.
LX<Jrrp12::
sUj:;plt:'mental iEed,
and m2cr:int:: cClpacit.y v:hile 7.r~e oL~t:c"tiv,
miGrt
be to maximize ~ross margin or minimize feec costs.
The g e n e r Cl 1 ma the ma tic a 1 for m 0 f
aLP pro b 1 en:
i s
n
iJ2ximize Z
l:CjXj
~>1
sUbJcct -;:0
n["
< t
,- i j x j
;
... = 1, ... , IT:
j:=1
x -; > C
j
= 1, . . . , r.
L'
I-j here
_ = I, 2,
••• ,
m
j ,
1,
2,
j ,
. . . ,
n
c~
price per uni"t of ac~ivity
Xj := jth 2.ctivity
dij = ~otal USClfc 01 resource i
in 2ct.ivity ~
b i := resource constraint i
Z :=
total
v~lue of th~ objective iunc~ion.
Proble~s with only one or two resource const.~8ints ccn cc
.:::olv,.::c Eeorr.etric::llly,
tr.osr:< \\..'i"th
thre.:::
or r.:ore.-
consc.f'3ints
C2n
be :clved tr.rough the sir.:plex ~ethcc (see h2cley,

---

U-' 8ssumul:ior.s.
ber'ore usinf' LP mccJels, onc r..ust
u~~~rst2~c ~ive critical aS~L~ptio~s.
! :e 2 C1
Cl n d
C3 n d 1 e r
(1 ~<5 <3)
Cl re
i .
Acdi\\:~v~tv
i\\(lditivity implios that ciil'eren-:: cc:.ivitiE:-5 sheuld
be
indepencent.
If production pro~esses Y1 cnc 12
feasible productive process.
This r.Jeans thaT there
must not exl~t Qny ir.toracticn te1:we~n prcuuctior
processes.
for ex~mple, using a rotational
cropping whore 2
legume crop prececes 3 cerE21 crcp
in order to increase the yield of the
latter,
represents 2 nor-cdcitiVE or
inTeraction situ2tior
anc must be
rEpresented 2S 2
sine:le c0r:ibineG
activi'ty.
2.
L .. nearitv or
"rc;)ert:"em:'.litv
Tr.e total input er oln:pL.:t of 2ny giv.'?n <::ctivity is
preportional 'to the level of that activiTY..
In
o"ther \\/oros,
i1' ?n 2.ctivity x 1:: possiblp.,
thE'n
every activity AX,
(A
> 0) is also possible.
For
example,
the price of a kilogram ot 2 supplemental
feed
is constant wh~tever the Quantity of supple-
mental
feea 5cld.
therefore,
C2n to used on 2
reduced or exp2ncec
scele without ch2r:gini;; the pror::ort:i-ons of inputs
2nc outtJut.

---

).
Divisibility
LP assumes the UGE oi re~ources ana procuction of
com~odities in Quantities that are
in fr~ction21
units.
In other words,
if the vector ~ de~ine~ a
feasible production process,
then the vector a~,
O<a<1 also cefines 2 feasible procuction process.
For instance,
in the optimal solution,
fractions of
cattle may be allocated.
This,
ho~ever, is not a
major problem and one can use integer proeramming
tc obtain desirable whole units.
4.
Finiteness
In LP,
the number of processes 2re assumed to be
finite,
partly because of da~a, time, cost and
interpretation limitations.
This affects the
degree to which conclusions may be extrapolated
from the optimal solution.
5.
Single-value expectation
It is assumed th::,t all
the technical coefficients,
such as prices, costs, etc. are knovn wi~h
certainty.
This makes an LP a deterministic
tool.
In cases where there is a need for sensitive
analyses on the optimal solution,
parametric
programminc may be used.
biological Fr2mework
~utritiondl Back2rouno
Undoubtedly, no sinele issue 2enerates 2S mcch interest
and controversy in the world as nutrition.
It
is not ~o

---

"- )'
j1
much tLa"t everyone \\,'ant.s to eat but every living crE'ature
must eut to sustain life.
Nutrition provides food and thus
energy :0 the living lody.
It is the major iec"tor of m~in-
te~ance, growth and
reproduction, ana protection against
many ciiseases.
Inadequate nutrition, however,
can c~use
disorders many of which are life taking.
In cattle production, nu"trition is a major factor
affec"ting productivity.
Cattle will not reproduce or pro-
duce at a low rate if their nutrition21 status is unsatis-
f8ctory.
The total energy intake is used "to satisfy,
in
decreasing order of priori"ty, main"tenance,
then growth and
finally the reproductio~ requirements.
Nutrition of Cattle
G[' 0 \\0/ t h and d eve lop r;: e n t 0 f
cat tIe are mark e d 1Y in -
fluenced by nutrition.
For example,
puberty generally
occurs at a particular body size relative to mature size but
can be reached at a younger age or delayed for several
months depending on the plane of nutrition under which the
animals are raised.
YounG females,
pregnant at pUberty,
will not sustain norm2l growth under 2
low plane 01 nutri-
tion for the latter cannot mEet the needs for both gro~th
and pregnancy.
Oftentimes, skeletal damage may occur i~ the
ca~ and retarded development in the fetus.
Conception rates will be low if female c~ttle are not
adequately fed ~t the time of breeding.
Denis a~d Thiongane
( 1 S7 2)
rep 0 r t e d a ~ 0 ve n; hto' 1r.l i n g imp r 0 ve DJ e n t i n rep roe uc t i ve
perform.:::nces ot le~ale Cccra Zebu Cuttlo wr:en they \\o!ere

---

32
raised on a high plane of nutri~ion.These authors found
that C[2 at first calving and calving interva1 1 we~e reGuce~
frcm 1184 to 933 days and 415.7 to 3~4.4 Gays,
respectively.
Unternourishmen~ 21so results in reduced ovarian acti-
vity and irrecula~ estrus in females,
poor libido and
abnorm~l spermatozoa formation
in males.
Overnutritiofl, on
the other hand, may cause large fat deposits and reduced
reproductive perforw.ance.
Eeef cow herds obtain the
majority of their nutrients by grazing forages which vary in
quality and quantity depending on the environment.
As a
res~lt,
cow-calf operations often suffer because of
undernourishment.
Feed Nutrients
The composition of a feed
is influencea by many factors
including the type of plent or grain,
the kind of soil,
the
climat:c condition, stage of maturity of the crop cnc the
processing me~hod.
To properly feed animals for maintenance, growth 2nd
reproduction, cry matter (OM) and four c12sses of nutrients
need to be specified.
These are protein, energy, minerals
and vitamins.
Vitamins will not be discussed here,
the
reader is referred to NRC (1984), Cullison (1975) and many
other nutrition manuals.
~mong minerals, only phosphorus
1
Interval between first and second calving.

---

and calcIum will be discussed becausE of their importance in
tt:e
tropics.
~~ergy.
One of the most common aeficiencies in beef
cattle is tr.e lack of sul'ficient energy.
The results of
this low energy intake are reduction or cessation of growth,
loss 01 bocy weight,
poor conception rate and increased
mortality.
The partition of dietary energy by c~ttle at
maintenance intake is shown in Fig. 2.1.
Net energy (NE) is the most precise energy measure
followed by metabolizable energy (ME) and then digestible
energy (CE).
Actual Ne hos been determined for only 0
limitEd number of feeds.
As a result,
the next best
measure,
(HE),
is commonly used.
Metabolizable energy is determined by sUbtracting the
urinary losses,
losses from methane production and
e~dogenous sources from the digestible energy (DE).
worldwide, different ener~y units have been used,
causing considerable confusion among professional,
technical
and loy people.
The following conversion fac~ors mBy help
to convert the energy values from one form to another:
kg Oigestible dry organic matter (OOr·i)
=
1.0) kg TUN
1 kg Starch equivalent = 5.082 ['!cE::! DE
= 4. 1 67 1'1 c a 1 i,j E
= 1. 1 5 kg '1' 0 N
= 1.1
kg DOh
1 kg TDN = 3.G2 Mcal ME

---

34
l::nergy of
- Feces (30)
Gross I::nergy-
( 100)
Energy of Urine (3)
Energy of Methane (7)
Digestible
Heat
Energy
Increr.lent
(70)
( 10)
hetabol iz'able
Energy (6C)
Net
energy
(50)
Fig. 2.1.
Approximate Dietary Energy Partition by Cattle
at Maintenance Intake
SOU r c e :
1': ear 1 (1 982 )

---

1 ' S
r:g
"
cano ln3 v .lan I''ee d U'nl'-;-~
(FU or ~L'U)
uI'
= 2.82 !-ica 1 [,':E
1 Kc a 1 hE =
(U F x
1 cH'!:::, )
+
et·'] e 0 i
i e e d
1 Kilo joule (kj)
= .2jS Kcal
1
KCCil
4.1b4 kj
Ki':ca 1 DE = • G2 Hca 1 !'-il::
ME for maintenance.
Maintenance energy requirements oi
ncn-lactating indigenous cattle in India ~nd Africa were rc-
ported by Kearl
(1982).
These values are 107, SO, 122, 121,
115 6nd 143 Kcal/w~~5 (w· 75 = metabolic body weight) with an
average of 118 Kcal/~~~5.
The latter compares favorably
with the value of 129 Kcal/w~~5 used by the NHC (19J8).
S~udies conducted in ~outh Africa (Va~ Rooyen, 197j) using
Africander, Drakensberg, Hereford and Simmental cattle
showed maintenance requirements for non-lactating animals to
be 115,143,137 and 115 J·,jE/Wk~5, respectively.
Neville
(1974) and Ranjhan (1980) used values of 137.4 and 122
Kcal/W~?5 to estimate metabolizable energy requirements for
Le
maintenance of Hereford co ...'s and Zebu cattle,
resr-:ectively.
The rei s e v i den c e (IV e bs t er,
1'.r! [3 )
t hat 1a r ge 2. n i f1~ Cl 1s
reauire less ME per kg body weight for mainten~nce th8n do
sm811er breeds 0xcept tor the heifers which require, at any
size, ~ore ME per kg of gain than steers of comparable
weight.
~E for gain.
~etaboliz3ble energy for ~aintenance and
gain was in ~hE r2tio 01 1 to 1.13,
respectively,
in
r.olstein calves ft"d 3 mi1\\<. ano concentrc>te diet (h~[l'es 2t

---

36
2 1,
1g 7'( ) •
T Cl era t i 0
\\/ (J s
1 to 1. 1Gin Af r i can Ge r cat t 1 Eo
(V2n Rooyen, 1975).
Ke2rl
(1~G2) ~veraget these ~wo valu2s
~nd obtained a ratio of 1 to 1.145 that was used
TO estimate
energy requirement for gain.
1~ e v i 11 e
an et·] c CuI 1 0 U I..: h (1 'J 6 C3 )
estimated the nE for maintenance and gain vith the l::quation
r'5
i'lE (Mca 1 )
=
1374 "",'./
+
6.3 gain (KG).
.
kg
ME for Preenancv.
The energy requirement of pregnancy
curinE; the first tLree months is about 40 KCel hE/day.
Supple~entation is not needed for female cattle in good
conaition, curing this period.
Mineral supplementation,
however,
should be prOVided at all times.
The energy requirements increase to about 235 Kcal
nE/day curing the middle trimester ancf to about 1 j·!cal/day
during the last triw.ester of pregnancy_
Beef cows, curing the latter stages of pregnancy,
require 150 percen"t of the j.;r; needed by nor.-pregnar.t females
(Kearl, 1982).
It is ~nown that nature gives the fetus
priority over the needs of the mother for available
nutrients anc severe deficiencies can first hurt the dam anc
then the fetus.
Kearl
(1982) suggest:ed that maintenance requirements be
increased by 30 percent during the seventh ~on"th, se percent
auring the eigr.th month and 80 percent auring the ninth
month of pregnancy.
He also indicated that tor browing
p re gn<: n t J e mCl 1e s,
the [T 0 \\{ t h f Cl c tor c [\\ n Ue c cd cuI a t [' d a oS t r: e
same as for non-pregnant heifers of the same size and
approximately the same ag~.

---

.. ...
,
'
In practice,
full
pregn~ncy requirements ca~not be ~et
\\.;iler. feed resources or,=, very limited.
Unless eneq;y
s r; 0 r tag e i s se ve re,
p re g n (; n t co\\>. S will sur v i 'lE: 0 n a i r Cl c t ion
of their enerfY demand and give viable calves.
~E for lactation.
Van Es (1976) suggested a value of
100 Kcal ~E/W~~5 for non-lactating females ana 11) Kcel
N~/0~~5 for lactating cows.
Tyrrell and Noe (1975) found
that lactating cows utilized the same diet approximately 12
percent less efficiently than non-lactating dairy cows.
KC2~1 (1982), after reviewing the lactation ~L requirement,
useC an 2verage value of 132 Kcal/w~~5 as mainte~ance HE
requiremen~
for
lact2ting cattle indigeneous to developir.[
co un t r i e s .
The NRC re c 0 mmen da t ion (1 578) was 11 30 Kc 3 1/ I;. g
of 4 percent fat corrected milk (FCM).
Pa~le and NUdgel
(197b) and Hanjhan et al.
(1977) working on local breeas in
I~cia found v8Iues of 11[1,3 and 1039 Kcel/kg 4 percent FCi·l,
respectively.
Sen et 21.
(1978)
recornme~ded that 1188
Kcal/kg of 4 percent FCr·; be used to calcu12te the r·1£
requirement for Indian cattle.
Kearl
(1962) stated that
there were only small differences in ME requirem~nts
between
breeds and geographic re~ions.
The latter author used an
average value of 1144 KcaI/k£ 4 percent FeN and found 930
KceI/kg 2.5 percent fC~ ior cattle indigeneous to developin~
coun-;::ries.
f'Jeville ana l:cCullol![';h (196Ll) estimC1teeJ tr.e di.Jily [·iL::
rtoquirement ior Ic::cTClting CO'dS to be filL heed = .1'/U4 v'k;'5 +
,; 2 ('air
(I,C)
+
,~ •
~
... 1.1.
y~ c..:.
"4 17 "'1 1•
(I.
)
. (
"i,)
1',1
r.r.r.
•

---

Protein.
Protein is ess€'ntial
tor mein'cenance, growth
2. r: c
d C' vel 0 pmen t
0 f
1 i. v i n[
t i s S lJ e s,
l' 0 r ~/ 0 0 1 fJ 0 \\i1: h,
milk
production,
enzy~es and hormones formation.
Tru(; protein is
the nitrogenous portion of fecdstuff that is made u~ of
.
. rJ
2r.llnO-aCluS.
Crude protein is the true protein plus the
~rotein equivalent of non-protein nitrogenous material.
Crude protein is calculated by multiplying the nit.ogen
content of feedstuif times 6.25 (the average nitrogen
content of amino-acids being 1b percent).
Digestible
protein (DP) per kg DM is expressed as a function of crude
protein (ep) by the equationDP g = 9.26 Cp1 - 35.2
(Demarquilly and weiss, 1970).
Protein requirements vary with the wei£ht,
pr.ysiological functions,
management system, feed resources
and expected performance of the animal.
Ruminants have the
2bility to synthesize much of their protein from non-protein
nil:rogen.
Protein deficiency in cattle diets le3ds to depressed
appetite, which in turn, causes low energy intake.
The
protein deficiency in diets also results in irregular or
delayed estrus, weifht lOSSES,
slow growth and reduced milk
~roduction.
A serious and ~rolon[ed deficiency in protein, causes a
decreaSE in protein content of the blood plasma acco~panied
by a tendency to forrl e.bnorrilal
2ccumuletions of ~12ter in the
1
C r u cl e
p r c t e i n
i r.
t nEO '=' Cl u;} t i 0 r, s i sex p r [' s s e ci 1 n jJ ere er' t .

---

39
tissues (ecierr:a),
piJrticulary in the extrer.:i ties,
chest anc
2l;oomiCn.
UP maintenance.
rh~re is evide~ce tnat the anirr:al's
response varies at 2ny given intake of protein depending on
the intake of energy (Lalch, 1S76).
~Ehring (1970)
suggested a value of 2.57 g OP/Wk~5 as the Qaintenance
requirement for c~ttle weighing 40C to 600 kg.
Sen et al.
(19(8)
recommended 2.84 ~ DP/W·75 for Zebu and crossbred
b
kg
cattle and Ranjhan (1980)
reported values rangin6 froo. 1.9i
to 4.19 g DP/w~~5 for cattle.
Kearl
(1982) used an average
value of 2.86 g/w~~5 to estiQate DP maintenance requirement
of cdttle indigeneous to developing countries.
DP growth.
Protein requirement Jor £rowth is more
difficult to determine than protein requirement for main-
tenance.
This is due ~o the varia~ions in nitrogen ceposi-
tions caused by the physic~l and chemical composition of the
diet and the age of the animal.
Also,
it may be difficult
to know if an animal is in negative or positive energy
bCl 1an c e .
Ge n t s c h et 21.
(1 9/5) ex p re s sed t 11 t: DP re qui r em en ~
for growth by the equation:
Kearl
(19l2) used the above equation and the average
1
LWC = Liveweight £ai~ in kg
LW = Liveweight in kg
OP
= Digestible protein in grams
8

---

LlO
rr:2inter.cnce value discL:ssec earlier to estimcn:e the GP
requiremen~
fer grewtr. and mainten2nce of ca~tle indigcnceus
Le
(~i::V, lcpin[ countrit::.'s c:s follows:
DP(g)
==
2.26 \\Jj~f5 + .218 U:C g + .6631 UI I:£
-
.G01142 Ui~g
The URC recommendCition for digestible protein is a cor.S~3nt
daily amount of 2.8 percent of dry matter consumption for
non-lactating cows,
regardless of age condition,
production
or physiologic3l stages of the CJnim2l.
OP oregnancy.
In general, there are no additional
nutrien~ requirements during the firs~ 6 to 7 months of
ges~ation.
However, during the £in21 2 to 3 months,
the
requirements for potein, calcium and phosphorus increase
mary.edly (Kearl, 1922).
Assuming that tLe average daily
gain Cl- products of conception during the l2st 3 months of
gestation is 400 g,
the author estimated the DP requirement
of pregnant incigenous cows during that peried ty aeding 80
g to the requirement of non-pregnant anim&ls gaining
comparable weight.
The 80 g GP are intended to meet the
reauirements of the developing fetus and membranes during
the last 3 mcnths of pregnancy.
However,
the cam and the
fetus 'Hill do well in caSE:' cl' minor shortC1ges whE:r'e ttle full
OP requirements c::Jnr.ot be met.
OP lactation.
Deef cattle indigeneou5 to ceveloping
countries are generally lOwer milk proGucers then ~r.eir

---

J1
count~rparts from Europe and USA.
the aver2gc milk produc-
tion of these cattle varies irom 200 to 40C kg during th~
1act a t: ion per i 0 d •
HC'W eve r,
d air y b r e e d s doe xis t
vi h i c r.
c 2 n
product 1~OC to 2COO kC of milk annually.
Lxam~les of
indigeous dairy breeds are Indo-P2kistanese Zebu cattle
(Cuzer2t, Saliwal, Red-~indhi, Gir).
[·];:;ny studies have been carried out "to determine the
protein requirement for 1 kg of milk produced.
Oftentimes,
the amount of protein per kg of milk is correlated with the
f2t content of the milk.
i'lehring (19'10) sU£8ested 50 to eo
g DP for milk containing 3 to 6 percent butterfat.
Ranjhan
et al.
(1977)
proposed 41.7 g DP per kg milk.
The NKC
(1972)
recommends 42 tc 60 g/kg of mi1k containing 2.5 to 6
percent fat.
Kearl
(1902)
used 55 g DP/kg 4 percent FCi·j to
calculate the DP requirement for cattle indigeneous to
de vel 0 pin g co un t r i e s •
j"; e 1 t S 1";
(1 979)
use d a qUE d rat i c
equation to describe the ~2ily digestible protein adjustmen"t
for lactation (MAt) of Brahman and British-crosses in North
and South Florida.
7he equation is as follows:
'Where
MAt is defined above
Mt is the daily milk production in kg
\\oft is the bocy .;e1[/':1:.

---

42
Dry i'la t "ter (OH)
T~e DH requirement is, gener3lly an estim2te of the
expEc~2d daily dry weigh~ of a particular ration ~ype
consumed by an ani~al under ad libitum conditions.
The
daily consumption by cattle is primarily dependent on body
size, .3f,e and condition as well as ration type and the
environment.
In general,
this consumption is in the range
of 1.5 percent to 3 percent of body weight (NRC, 1984).
for
beef cows on rouehage,
Chu rc h (1972) found that tc;e uppe r
limit of voluntary OM intake per day approximates 2.5
percent of body weight.
Friot et 81.
(1980)
inciicated that
the upper limit is about 3.3 percent of body ~eight for the
Senegalese Cos indicus, Cobra Zebu.
!'iinerals
Calcium and phosphorus represent more than 75 percent
of the tot2l rr:ineral contcr:t of the anirr.al body.
Cullison
(1975) reportee values of 49, 27 and 24 percen~ for Ca, P
and other minerals,
respectively.
Ca 1c i urn (Ca)
~iine~y-eight percent of Ca
retained in the body is in
the bones.
The remaining 2 percent is found in the blood
and soi~ tissues.
~hen high demands for Ca are made on
the
body such as during t~e late pregnancy or lactation, calcium
is absorbed from the bones to meet the increased demanc.
The symptoms 01 deficiency include retarded bone growth
(rickets) and en thr i fty a;:;pe2 ranee in young an imc:l1 s,
o .s t e 0 i::;:' 1::; c i c: ;:; ne
rE: C U C f:? cl
IT; i ] k
pro Cuc t j en in::; ci u 1 t s •
Exco~s
" .

---

Ca may ~avE an anta[onistic effect o~ severnl other minerals
such 2S pho~phorus, m3rr2~es~ and zinc.
'~ r~ e l\\: r< C (1 C) e4) [' e c 0 IT: ml' n d a tic n f 0 [' i.i n i oS r. i ~ r c 2 t t 1e is 2
gcarr:s of P and
1 g of Cc:
l'or e3ch 1CO gr<:lms 01 p'otein r.,e-
quired for maintenance.
In lactating cows,
DRC (19b4) also
r~commends that 2.7 €
01 Ca and 2.0 g of P per kg of milk be
added to the maintenance requirement.
Calcium occurs in low amounts in most cer~21 grains and
S~['2WS, in moderate ~mounts in most good quality forages and
is abundant in fish,
mea~ and bone meals.
Supplemental
sou['ces include steamed bone meal, dicalcium ~hosphate,
ground limestone ana defluorinated phosphate.
Phosphorus (P)
T~e skeleton con~2ins 75 ~o 80 percenT of the body's
phosp}~orus.
Tt1e symptoms of phosphorus deficiency dppe2r at
an earlier
staee tr.Jn do those of Ca deficiency.
Repro-
Guctive failure is the most devastating Economic result of P
ceficiency.
ether sytnP~orr.s include decreased appetite
followed by deformed appetite (pica),
recuced rate of gain,
depressed feed efficiency,
stiffness oi bone joinTS,
rickets
and cs~eomalacia.
E~cause the soils in the
tropics are often deficient in
P,
low levels of this element in pasture and other rougha[e
fee~s are common,
p2['ticularly du['ing the rainy season ~r.en
the for<1ge
is abundont.
Phosphorus content cenerally ce-
erE c.~ ~ e s r.: () r ked 1 y ().s t r, e p l.J n t :::: m.3 t u r e 2 nd ~ eve r t'

---

deficj.encies alter. eccur in cattle subsistir16 le!' lonE time
or. mature dried ferage.
The requirements are as the SDfnE 2S those mentienec
.
above.
Phosphorus is le',; ir. forage crcr::-s,
but higher in
l88ume crops, cereals and their by-products.
0upplements
include dicalcium phosphCite, defluorinated phosphate,
['ocJ..~
phosphate and bone meal.
GrO\\oith
Crowth can simply be defined as either an increase in
size or increase in differentiation or both.
Crowlh can be
expressed as kg of live weight at a given time.
The
mechanism of growth in animals is very complex and ils
aiscussion is above the scope of this' \\oiork.
for aetails,
the reader is referred to Seebeck (1960), ?alsson (1955),
8utterfield (1966),
Brown et a1.
(19'72a;
1972b;
19'(6),
Drod y (1 SI 45 ), C:: r t \\.; rig ht
(1 <:9 70), '1.'2 y 10 r
(1 s: G5 ), Tay 10 ran c
Fitzhugh (1971), 2nd Huxley (1932).
The ~eight-age relationship is commonly used to
describe Growth in anim8ls.
Although the specific shape 01
the growth curve (i.e., weight-age) varies from breed lO
breed (Brown et a1., 19(2),
the overall shape is
sigr.:oical.
t'lany £rowth functions t:2.ve been rroposed but
those commonly usec are from Brody (1S45),
Bertalanffy
(1SGO), 'dinsor (1932),
l:elder (1961), and Ricli2rds (1<])9).

---

Chi:. PT Et.;
II I
~1t:THODS OF ANALYSIS
In this cheptcr,
the two models used in this study Cire
descri~ed.
These models are nutrient requirement
s-..::mulation model arId economic model.
Nutrient Recuirements Sir-JUlation [·:odel
(t·le 1 ton IS i·1ode 1 )
We have seen in Chapter 11 that one way to specify beef
cattle nutrient requireffients is through the use of th~
recommendations of the [·iational Research Council
(LRC,
1984).
'J.he se recomfliend <:: t ion s,
others,
l:o~;ever ,
may b2 inappropriate for herd a~d ~nnagement conditions
specil'ic
to Lahra,
beccn.:,se they are general in n<..iture Gnd
fail
~o reflect differ~nces in nutrient requireffients due to
breed, environmental and physiological conditions of the
breeding stOCKS.
Fu r the rr.:o re,
~!RC rec orr:menCCl ti ons a re
i r.
the form of daily requirements per animal and need to be
3[gregated over both time and animals when one wants to
evaluat~ the herd nutrient requireffi2nts over lon£er ti~c
This aggregation may result in
serious errorJ.
Because tr:e rec;uirt.:d cffiount 0'::' each nutrient is
cdfected by numerous and interre12ted variablE:s such as
genetic potential, age,
physioloEical conditions and
en vir 0 Cl fI'to, n t 0 f
the 2. n i iT! Cl 1 l
2
rr. e "[ l: c dolo gy
t hCl t
80 d i 1 i e s
0:: n(1

---

46
supplements NkC recommendations to reflect these
ir.L:2rr2131:ion.sl~ips, h2S been suegested by [';eltor. ('11)79).
The
2ppr02ch usea by i'lel ton considered growth 25 the best
reflection cd "the in-:errelateu Ec'ffects of genetic ana
enviro~~ent~l veriables on the animals.
In other words,
lor
eny breed of animal
in a given environment,
there is a
£rowth specific to that environ~ent and nutrien1:
requirements chsr2cteristic of that growth.
Cry mLltter,
ener[y and protein requirements are expressed in the mocel
EJS follows.
DH Requirement
Assuming tt-at tb:? dEJily" cry mat1:2r intc;ke 01' beef CC~iS
is m percent 01' theIr body weight,
the DH requirements cl' an
animal in the cow herd C2.~ be expressed as
\\i (; ere
= ~eighL: cf jry matter intake, in kilograms
(kg)
by 2. cow on day 1:,
W1: = cow's body weigh"t,
in kg, on cay t.
From Lrody's growth model,
'tl .
A -
El e - k t .
L:
where
Wt = weight a1: time
H
2. S YmP 1: 0 1: i c
....."e i g h t o r ma t u re',: (- i g ht,
c
i r. 1: e f, re: tic l'
con oS t G n t ,

---

e = base of na~ur2l logarithm 2~d
K
r2t~ 01
maturity.
~ e L t i ~, r r;: == • Gj
for Cc b r <1 Ze l: u i n iYa h r ~',
To ceterr.line the expecteci dry matter consumptior. Ol an
2r.im21 over ~eriods of time greuter ~han onc Gay,
Gn~ ~eeGS
to irtegrnte the function over the appropriate t~me interval
oi' tr~e 2~im21's lit'e.
Tre
recom~~ndec dry ~atter for an a~imal oi ag~ tu over
L.1
t 1
Of-' ,
= .03 ./ (A
'1
==
f
Ol-It d t
t c
t e
0["!i
ury r.12tt:er required over the Spt":::iliec tin:e
interval for an animal
in the ith group.
'~t]is int.egraticn is jJerfcrmec fer ez:c(; 2,[0 froup or
closs represented in the co~ r.erd.
Over 2
specified time
ir.t.erv2l,
the t.erc ory matter require~ent can be ey.prEss~d
2.S
r:
[;-:
==
L ().
DI'-'; l'
1
i=1
[. l :
cry rr. a t -::. c;--
, ::: cui r e r:: e n t
0 f
the r, L: r d :J V er;:: r: e
s~ecifiet
time interv2l,

---

4(;
number
f'
C ...
croup,
h t~ r 0 •
Lnerc.v Heaui rerren-(
lis-ville
enc l';cCullcugh (1':)lb)
t12ve
estirr,8tec the Gaily
ME requirement of a cry and open cow as
Iv' he re
f< Et::: (,1 L
reo u ire d bye n 3 n i lTi,:; Ion cl (J Y l,
d(A
-
Ee- kt )
l.~
:::
;1" Be - I', ,-
:::
\\ ' ,:, i
,- n' L
",
.. ~ _
~
I L.
[£ ::li r. ,
CT
dt
i~ kilograms of the animal on day t.
'"It.e
ccily ~,;l requireoent ~E:Y be expressed 2S
l~e energy recomme~~ed for a dry,
open and growinf
fem2le or 2ge t
ev~r ~ Deried (t C-t 1 ) is abtainvc by
intefratien 2S
1: 1
i:Li:::
f
[,'Et et.
"CL

---

4'::;i
= • 1 ~ '14 f
'.ihEre
(';£i
l-:E requi ree
by
the i th age 01 or:im2l over 2
spEcified ti~e interval.
\\d t h n c g e g r 0 ups and Cl i
C1 n i ma 1 sin
e3 c r: g r 0 up,
t f: e her c [,1 L
requirement for non-lactating and open cows is
n
I
Cl.
I·IE·
.
1
1
1=1
Lactation Adjustment for ~nergv
IJeville and ;·icCullough (1968) haye estimatec the daily
MS requirEment,
for
lactating cows,
to be
....ihere
U!E t = c<:lily hI:: requirement for 3. lactat:iilS non-
pregnant: cow on day t
of lactation.
M
= daily mil~ procuction in kilogr8~s.
t
For Erahffian cows in the tropics,
Neidhardt e~ al.
C'1') t , ....
•
LL4~t:
-
For 2. co~ in ThE ith cge group producing a given amount
of milk (MO) per d2y over 2 specified time interval (tc-t,),
the tit: required is obtained as

---

50
Lt': E:
t 1
. t 1
.1(84 f
(A - Ce- kt ). 75 dt + c.2 J
hBe-ktd~
to
1:0
t 1
+
f
.7443 l'i t dt
to
The lactation adj~stment ior the ith group in the
LA ,
= UI£· - tiE;,
l
1
1
Pregnancy Adjustment for Lnerpy
The energy required by the fetus for normal growth is
accounted for when energy recommendation for pregnancy is
expressed.
For a non-lactaL:ing cow the added daily Mb
requirement is expressed by ~oe and Tyrrell (1971) as
P',: c'.
=
'" ,- 7
.01 7 1.[ ~ 75
[d:-1:
",..,0
e
r l
\\lhere
PME t = daily ~E requirement for pregnancy on day
t
of gestation,
1'1 i
a v era g ewe i g h 't 0 l' the i t h co 'tI g r 0 upin
kilogra~s en the date of conception (i.e.,
when t = 0).
The HL requirement for pregnancy of the ith age group
of CC'tlS
is derived by integr2ting hS iollo~s:

---

51
t 1
PA.
Pi·iE· d t
~; ~ 75 J
. 5G'(e· 01 '/tdt..
1
"t
1
t c
By summing up tne adjustments and base requiremen-cs
wei£hted by animal numbers, we can obtain the total energy
requirement of the herd.
This is expresseu 0S
n
tv1E = 1:
+
B·
LII·
+
y.
PA . )
1
1
'1
1
i=1
where
ME = metabolizable energy requirement 01 t.he herd
over the specified time interval,
.
Bi = number of 2ni~als in the ith group "that are
lac ta ting, 2nd
~i = number of animals in the itn age group that
are pregndnt.
All other variables are as previously defined.
Protein Requirement.
The NHC recommenda"tion for digestable protein is a
daily amount of 2.8 percent of the daily dry matter consumed
by non-lactating cows.
Using this figure,
one can express
the daily digestible protein requirement as
GP t ::: (.03) ( . 028 )l-i t = .00056 i; t

---

where
ep t == cL) il Y d ibe s tibl e protein req u i rer.:E'm: in
kilogr3ms.
The requirement of an animal of agE' t over ~he interval
•L.1
DP i == f
DPtdt
to
t1
==
.00U56 f
(A
-
Be- kt ) dt
tc
\\01 he re
DP i == digestible protein req~irement in kilo[rams
of an animal in the ith group over the
specified time interval.
Lacta~ion Adjustment for Protein Requirement
~E'lton (1S79) used a quadratic equa~icn to oescribe ~he
iJRC recommendations.
This equation is as follows:
..,;here
MAt == daily digestible protein adjustment for
lactation
,,'
l'l~
==
daily ~ilk proQuction in kg.
~he Qdjustment over the interval (to-t1) is expressed as
~1
{"~Ai == f
(,:A~ dt
t c

---

53
The digestible protein requirement of the herd is
obt2.ined 2S the weighted sum
n
DP
[(Cli DP i + (~i t';A i )
i=1
'rlhere
Si = number of lactating cows in itr. age group, and
all other variobles are as previously defined.
Economic r'10del
Linear programming (LP) was chosen as the mathematical
model for the economic analysis in this study.
Before we
discuss the dct2.ils of this model,
it' is notevlorthy "to
present a brief description of the firm.
'The Firm
The firm analyzed in this study is a single production
unit consisting of 5900 ha of government owned lond.
Available technology and high level of management can be
efficiently utilized.
All ldnd is used to grow rainfed
forages for beef cattle production.
No crops are grown on
the farm.
The forage system includes tropical grasses 2nd
legumes which are predo~inantly Tepnrosia sp. Phyllantus
pentadrus,
Aris"tida stipoioes,
Andropogor. amplectens,
Erogrostis tremula and Zornia glochidiata.
There are on the
average 78.9 percent annual and 21.5 percent perennial
species.
The 2v~r2ge nu~ber of shrubs is estimated G~ 260
per ha.

---

54
Cow-cnlf operation is the beef cattle en~erprise of
i~terest.
All calves are born on the f2r~.
~o co~s, c~lves
or bell.:> are j:;urch<.:sed fro~ other beef enterprises.
tJrociuc-
tior. is res~ricted to one cattle bree~ and one calvin[
se~son.
No supplemental feed
is producEd on the farm.
Econo~ic analyses are conducted to determi~e the least-cost
rations.
The LP ~10d e 1
The objective of the firm is to minimize the cos~ of
L:tilizing supplemental feeds "Co satisfy the COVi herd re-
quirement during the long dry se2.son \\'ltlere natural p2S1:L:reS
are severely curtailed in quantity and quality.
The linear constraints (Cede,
1960;
Heady et 31.,
1958) are the minimum and maximum dry matter
(OM), meta-
bolizable energy (riE) , crude protein (ep) ana the quanti ~y
of feed in each period of the year.
The periods correspond
to the physioloeical stages of the female Gobra a1: Dahra and
are as follows:
Arril - June:
last 1/3 of gestation
Jely - September:
first 3 m-:mths post-p2r~um
October - December:
3 month period from breeding
season through weaning of the calf
J2.r:L:ary
"
,
- "Iarcn:
3 months from weaning through, the 2/3
of gestation.
The model
is represented in standard algebra as follows
(Heady et a1., 1958):

---

5')
.q
n
['.: in C =
1:
i:
!-'jk Xjk
j=1
k=1
~,ubject
to
q
n
D1 < 1:
1:
A1 jk Xjk < t;1
j=1
k=1
q
n
D
<
1:
2:
A2 jk X-;k
2
v
j=1
k =1
q
n
B
<
1:
1:
Aj -,~. X
3
jk
J '
j=1
k=1
X··
> 0 for all j = 1 , ... , q
JK
k = 1 ,
.. ., n
where
C = annual supplemntal feed cost to be minimized
Xjk = quantity of the jth feed used in the k~h,
perioG
Pjk = cost per unit of jth feed in the kth period,
q = number of supple~ent31 feeds,
n = number of supplemental feeding periods,
81 = minimum OM requirement,
8 1 = ffiC)ximur.l Dj·! requiremen'C,
B
=
2
minimum ME requirement,
2 3 = minimim ep requirement ~nd
A1 jk , A2 k and A3jk = DM, NE and CP concentrations
j
of jth feed in kth period,
respectively.

---

CHAPTER. IV
DATA DEVELOPMENT
The daLa used in the models discussed in Cr.~pLer III
are presented in this cr.apter.
Growth,
forage and by-
product price data are described along with the input da~a
usec in the nutrient requirement simulation model.
CrO\\·;th D3 t2
Tr.e cattle breed used in this study is Cobra Z~bu.
The
growth of these animals is measured by taking their body
~ei£ht at constant time intervals from birth to Qaturity.
Each female Cobra is weigned monthly from birth to two ye~rs
of 3ge, quarLerly from two years to six years and every
semester Lhereafter.
Data collected on 1589 females were
us~a to estimate Lrody's Ero~th curve porameLErs for Cobr~
lebu females (Abassa, 1984).
Cobra cow growth curve was ex-
.
I.r
790 8~
402 ~- -.0018t
presseG as ~t = ~ u. )
-
./~e
•
The aver2f,e 2~d
total weaning weights of Cobra calves for the averaee,
driest and rainiest year are presentee in Ldble 4.1.
Forage Data
Published seasonal Cat2 or. forage yields in the Sylvo
pasLoral zone in [er-erel Gnd in uahra in p2rticular, are
available (Raynal,
'1964;
Valenza and Fayolle, 1':165;
Denis
ar.c V2lenza,
1S75;
Bi11e,
1971;
Denis and Ihiongane, 1972;

---

') ~.
- (
Table 4.1.
W~aninG Weights of Cobra Zebu CDIves Gy
Production YeC"'r
l'lean ing
Total ViE:aning'*
Year
weight (kg)
weight/100 c~t;
Driest
91.70
4589.5e;
Average
114.90
5~(50. 74
Rainiest
102.70
5140.14
Source:
Abass2 (1984).
'* Total weaning weight per 100 cows ~2S calculated basad on
60.83 percent pregnancy rate and 87.22 percent weaning
ra te.

---

Boucet, 1:3'15;
13i11e, 1St'!;
Cornet and Poupon,
1975;
Cor ne -'-L.,
1 87 ','°).
v
In ~his study, ~ value ef 1150 kg of [~ per hectare is
used "to represent the ~nnu81 average foreee yield in Lohra
(Corne-c, 1978).
The yielcs of Dt~ per hectare for the criest
and rainiest years are represented by 762 ke (Cornet ~nd
Poupon, 1978) and 25CO kg (Denis and Valenza, 1975),
respectively.
Only 33 percent of these amounts are available to
animals during the dry season (Valenza and Fayolle, 1965).
The quantities of OM available from January through July of
the average, driest and rainiest years are estimated at jB4,
254 and 834 kg per hectare,
respectiv~ly.
'The quality of forage is measured in terms of protein,
energy, mineral and vitamin concentration.
The seasonal
values used in the economic analysis for an avercge produc-
tio~ year are listed in table 4.2.
Quality values are
unknown for the driest and rainiest production years.
Analyses will be performed using 100, 90, 80 and 70 percent
of the qu~:llity values of' 8verage production year to repre-
sent driest year and 100, 110, 120 and 1jO percent to repre-
sent possible rainiest year's values.
The quality of the
browse is assumed cons~ant for all production years.
Supcltmental Feed Data
The browse represents the most common supplementdl feee
available to the animals during the 7 month dry season, when
the torage is curtailed
in quality and quantity.
Thou£h

---

•
59
Ta ble
,
....
L~ • c... •
~utritive Values (AS bSD) of Forage in Dahra:
~easonal Oistribu~ion-Average Prcduc~ion Year
I!U tr ien ts
Ji:Jnuary-
t.pril-
(per kg AS FED)
Larch
Jun~
July'l
Dt-l kg/kg
.931
.945
.949
ep g/kt,
47.37
42.63
30.65
OP kg/kg 2
.009
.0('4
.0(;(;
HE Heal/kg
1 .722
1 .661
1 .570
Ca g/k£
4.16
3.06
2.94
P g/kg
.52
.31
.22
Sources:
SOOESP (192-0-81);
Der.nis and Thiongane (1S72);
Eo'riot et a1.
(1980)
1 June values are used for July to reflect the conditions of
beginning rainy seasor. where the overall actual nutrient
conten~s of the pasture are increased but due to fermented
straws, appetite and intake are reduced.
2 OP = S.2~*CP (~ of feed) - 35.2 (Demarquilly and Weiss,
1970)

---

GC
this is well recognized by many researchers,
only a few
Guthors h.::.ve investigLlted
tile Dt-I yield and the nutritive
value of the tro~se in the FerIo zone of ~enegal (Eille,
1S;'(l);
1()T/;
Dio110,1968;
Fotius and V<:lIenzCl, 1S('t.;
.be
H0 u e r 0 u,
1 <) E3 0 ) •
SiIle (1977),
working in Fete-DIe, estimated that 40 kg
of m'] of broHse are mace available
to the animals per
hectare per yc~r.
Using this figure for Cahra research
station, one would expect 236 metric tons of DM provided by
the browse end available to Cobra cattle during the dry
season, every year.
Sille also found that the average
energy and digestible protein contents of the browse were
2.695 ('Ical (.9 UF) and .100 kg ~lE per :kg of CH,
respectively.
A comparison of Sille's energy values with
thOSE in table 4.2 confirms the finding of Le Houerou (1980)
who showed that during"the dry season, the DM energy content
of the browse is about twice as much as that of grass
straw.
Table 4.3 exhibits the nutritive values used for the
browse in Dahra research station.
Agricultural and Industrial Ey-products
The amount of by-products available in Senegal and
their nutrient concentrations heve been investigated by
;·10n[;odin and Tacher (1979).
Ti:ey are listed in table 1.5
end
their nutrient concentrations alon~ with those of other
supplemental ingredients are found in table 4.4.
:'.;;'
.

---

G1
'i.'<:lbie
4.3.
(':ut,itive Values Used fa,
Browse
in Ddhr~
[lu tr ien ts
Ju n uc) r y-I·!a re h
tpril-July
Oh (kg)
1 .00
1.00
UF/kg m,
.90
.f,
OP kg/kg CH
.100
.100
[:lE
f']ca 1/ !,g Dr·]
2.70
2.51
C2. g/kg Oh
).38
S.;;/:)
p g/kg m~
2.24
2.24

---

TcJ b 1e 4. 4 .
l'J u t r i e n t
Con c e n t r d. t i 0 r~ (1\\ S FL. U) 0 f
Fee d s
t, vail", tJ 1e l'0 r the l' .0 r 01 u 1c t ion 0 1
S~~plemental Rotions
F'eedstufi' name
Orfj
( I~f )
UP (kg)
~m (Kcal)
Uf
C3
(g)
p
(g)
l~ r e VI e r I s d r i e d
grains
.9H3
. 1'14
2.55
.('1
.2C
-:<:('
../':)
I(ice polishings
(;
midds
.924
.124
2.543
.eo
1 .2S:
1 .12
CGne molasses
.1311
.GOD
2.299
. '/9
· '/1
.02
~orghum straw
. '1'/4
.01 'I
1. 7'/2
.53
.29
.OG
jH lIe t
s t r Cl w
.900
.UUG
1 .521
.33
· 01
.00
Hice s t ['Cl v:
.e8<)
.005
1. 492
.32
.20
.02
Groundnut
c-
l\\-)
straw
.927
.0Gu
1 .944
.54
1. 21
.17
CowpeCl straw
.893
.088
1.759
.46
1.20
.25
Groundnut meal
.935
.444
2. ri1 2
.95
.V;i
.55
Cottonseeds
.926
.13'1
2:713
.95
.0[;
.06
Urea
.990
1.464
.oco
.coo
UicnlciuflI
phosphnte
.LOO
--
--
--
1£26.4
140.6
Colcium
cC1rbonnte
.COO
--
--
--
JUO
Groundnut
hulls
.9j1
• (j1 3
.0Ge
.OGO
• H:J
. C4
f, C <:: p t e ci
i r' 0 m:
Mongodin and T~cher ( 19'(9) ;
Ke8 r 1
( 19[;2)

---

63
Ci.1t3 Usec in ('lE 1 ton's r:oce 1
The following variables nEed to be specified in
lie 1 ton I s l";oG e 1 :
1.
Cow i.1ge-classes
2.
Weaning weight of calves by cowagE-class
3.
Qunlities of cows based on their milk prociuction
4.
Time variables
age in days of calves
days of pregnancy
days of lactation
days since weaning
5.
Growth curve.
Cow Age-Classes
The Gobra Zebu cow herd is partitioned into 9 age-
classes which are shown in table 4.5.
This classification
is based on production pErformances of the animals.
Cows
with similar performances are confined in the same group.
Weaning Weight of Calves
Unadjusted mean we2.nin~ weights by cow af,e-classes were
obtained from growth data collected at Dahra research center
and are shown in table 4.6.
Qualities of the Cows
Unpublishea data on milk production of Cobra were useo
to recognize five qualities of cows in the h~rd.
The m~an
daily milk yield and stancdrd deviation were estim2ted at
4.~4 and .64 kG.
Clnssification was based on one and two

---

64
7able 4.5.
Cow Age Croups and Co~position of 1GO-Cow H~rd
Classes
Age in years
Percent.::.ge
1
2
0
2
3
20
3
4
15
4
5
15
J
6
15
6
7
15
~
I
2-10
10
8
11-12]
10
G
. /
>12

---

• <.,
b5
Table 4.G.
~e2ni~g Weights of Cobr3 ~ebu Calves by Co~ Age
Grcup
Age group
v'eaning \\.;eights
( kg)
')
'-
99.0S'
-:z.
./
100
4
108.18
5
108.63
b
110.45
7
112.27
8-10
111.81
11-12
100.90
>12
90.4S

---

stande-rei deviations belo,,; dnd above the mean.
The qualities
are presented in table 4.7.
Time VcHiables
Each of the t\\.:elve months of the year is SE::t to include
::;0.5 days.
Age in days of calves.
In Dahra,
the first month 01'
production year (i.e.,
beginning of calving season) is
July.
The weaning age is six months.
At the time they are
born (in July), calves are 152.5 days short 01 their ~eaning
age.
The age values (T 1 ) in days of the calves from birth
to weaning is displayed in table 4.8.
Days of pregnancy.
Days of pregnancy (T 2 ) are shown in
table 4.8.
Females are bred in Octooer in Dahra.
Therefore, the cow which ccnceives in October is 274.5 dayS
pregnant at the end of July.
Davs of lClctation ('1')1.
The number ot' days or'
lactation since calving (in July) are 30.5 and 21j.5 at the
end of August and January,
respectively.
The values of T~
. /
are shown in table 4.8.
Davs since weaninp.
The last time varible is the age
of calf in days since weaning (T 4 ).
Weaning occurs in
January-February.
At the end of Marct;, calves are 30.5 days
old.
The values of T4 for the twelve months of the yeClr are
shown in table 4.8.

---

Table 4.7.
Cow Quality Grou~s
.
j··:i lk production
performance
Qualities
Groding
kg/day
1
Excellent
6.02
2
Good
5.j8
:J
Average
4.7~
4
Low
4.1
5
~oor
3.4(.

---

Table 4.8.
i'ionthly V".dues of 'i'ime \\lariat'looS
I-lcntr.::J
(,.
T"
.I.')
L·
I
'1' /1
L
->
A(F'eb)
-152.j
122
0
C
b(tiarch)
-122
152.5
0
30.5
C(April)
-<:11 .5
183
(;
01
1 O'iay)
-61
213.5
U
91.5
2(June)
-30.5
244
(:
122
3(July)
0
274.5
0
152.5
4(Aug)
30.5
0
30.5
183
5 (:::Jept)
61
0
61
213.5
6(Oct)
91 .5
0
91 .5
244
7(rlov)
122
30.5
122
274.5
8(Dec)
152.5
61
152.5
jU5
9(Jan)
18.3
91 .:)
183
j35.5
A(Feb)
213.5
122
213.5
366

---

69
Pr iCE Da td
For~ge~
The for c. [, e pas t u r t~·.s g r ~ zed by Cl n i ma I s <J t
[; e::t I C a
C' C oS ear c h
station are strictly rainfed.
TI:eir- rrociuction cost is.
nil.
If they are not grazed by the herd,
they have no
alternative use.
Their opportunity cost is,
ther-crore,
nil.
This is not surprising if one recalls the description
of tne physical environment and limitations of FerIo zone
where nothing but stockcaising and some acacia gum
cultivation are practiced.
Supplemental feed
The supplemental reeds available for feecing beef
cattle in Senegal were presented in the previous section.
Distances between production areas of those used in this
study have been calculated ar.d are shown along with their
transportation costs in t2ble 4.9.
Their prices for 19bj
are presented in table 4.10 (Oia110, 1983).
Table 4.9.
Distance Eetween Shipment Points and Related
Trar.sportation Costs
Shipment
Distance (km)
Transpor ta ti Ofl cost
Points
from Dahra
(FCf'A/kg/km) to Dahrc
Dakar
267.2
10.66 (14.96)*
Sangalkam
252.4
10.07
Diourbel
119. '(
4.'17
St. Louis
158.7
6.18
* Urea transportation cost

---

'l'<Jule 4.10.
~;upplemental l·'eed Costs (FCl·'l\\)
'1'r8nsportation
cost (FCFA/kg/km)
Market price pEr period*
Feedstul'f
jiG r 1< E t
to Dahr8
I{JH)
II(AJ)
III(J)
Erewer's dried grains
~ang81kL1m
10.0'1
16.0
16.0
1b.O
IUce polishings and rnidds
St.
Lou is
G.18
2:5.0
2~,. 0
2j.o
Cane rnolDsses
~)3ngCilkam
G.18
28.0
28.C
28.C
So q; hum s t r .:1\\-)
Diourbel
4. T(
2.5
16.0
16.0
hillet stra'vl
Oiouruel
4. T(
2.5
1G.0
10.0
kice straw
~jt.
Louis
-b. 1 U
22.0
:::2.0
22.0
---.:
Croundnut stra'vl
Diourllel
4 • '/'1
9.0
1G.CJ
16.0
C'
Cow pea s tr8 ....'
Diourbel
ti • '1'1
9.0
16.C
1 Ll. 0
Groundnut fTJeDl
u<.:kar
10.6G
4 'f .00
4 'I • Ob
117.00
Cotionseeas
Dak8r
10.GG
35.08
:::5.(;8
25.0G
UreD
081', Cl r
14.96
?-5.0
25.0
25.0
Dicalciurn phosphate
Dal<a r
10.66
25.U
25.0
25.0
CDrbonate phosphate
uakar
10.6b
105.0
105.(;
105.0
Groundnut hulls
Sang811<am
10.0'1
5.0
5.0
5.0
Source:
Oial10,
A.K.,
p~rsonal cornmunitions (1903)
* JM = Janu8ry through March
AJ = April through June
J
= July

---

CHAPTER V
RESULTS AND DISCUSSION
This chapter presents the results of nutrient re-
quirement simulation and economic models described in
Chapter Ill.
Economic analysis was perfor~ed to minimize
the costs of feeding Cobra Zebu cows using the data deve-
loped in the preceeding chapter and nutrient constraints
obtained from the simulation model.
Nutrient require~ents a~e shown for each of the 9 cow
age-groups discussed in Chapter IV.
Analyses of feeding
strategies are presented to correspond to the conditions of
the average, good and poor production year.
Year classi-
fic6tions are based on rainfall and dry matter production.
In an average year,
1150 kg of dry matter per hectare are
produced.
The good and poor years correspond to 2500 and
762 kg of dry matter produced per hectare per year,
respectively.
A fraction (e.g.,
10, 20, 30 percent) in-
crease in forage quality refers to that fraction increase in
forage quality of the average production year.
There are 3 feeding strategies corresponding to the 3
types of production y~or.
Drood cows are allowEG ~c lose
weight (i.e.,
to consume less than their requirements)
during the last qU2rtcr (April-June) of the pregnancy.
Thus, unless specified, E2ch feeding stratecy is discussed
71

---

vlith re3pect to (1)
managefnent system (System I) v/here 100
percent of the minimum requirements are met,
(2)
management
system (System 11) in which only ~5 percent of the require-
ments are r;;et,
(3)
management system (~yster;; Ill) where 90
percent of requirements are satisfied and
(4) management
system (System IV)
in which the manager chooses to provide
only 85 percent of the requirements.
For the rainiest year,
un 1e s ~; s pe cif i e d,
ea c h rn a n Cl g e fil e n t
s y s t em i sdi s c us sed wit h
respect to 0, 10, 20 and 3C percent increase in forage
quality.
j·lanagement systems in the dl'iest year 2re dis-
cussed with respect to 0 and 20 percent decrease in forage
quality.
C2rrying capacities of the rang~land are presented for
a sin[le cow in each age group and for 100-cow herd.
Least
cost rations are discussed along with optimal supplemental
feed costs for each system.
Period I,
11 and
III corresponc
to January-March,
April-June and July,
respectively.
Forage resources are used to the maximum amounts and
the requirement'oeficits are met by supplemental feeds.
The
daily dry matter intake of fE:'males in 100-cow herd is set at
2.5 percent cf body weight at lower limit and 3.00 percent
at upper limit.
To determine the levels of nutrient defi-
cits when a sir.gl~ cow in each age group is raisec only on
natural pastures, c2rrying capacities are estimated based on
maximum daily dry matter consumption.
Urea and cane
molasses are provided at 1 and 10 percent of the total diet,

---

respectively.
Values useo 10l' jJhosphorus (P) and calciurll
(C3)
ore ad~ustec t;l{C recorr:mencntions.
Lono is not c. liQiting ::,'actor of production in Laflra.
The rainfed forages produced on this land are extrerr:ely poor
in P and fcirly good sources of Ca.
Preliminary analyses
show difficulties in satisfying the P requiremc~ts without
inflating Ca arr:ounts to toxic levels when forage and supple-
mental feeds are used.
Therefore, P deficit is met by a
supplemental activity and its cost is excluded from the
optimal solution.
The average calving and weaning rates in Cahra are
assumed const2nt across all production yeers.
It is assumed that sufficient amounts of supplemental
feed incredients are avai12ble in the market at 1923's pre-
vailing prices.
Optimal costs of supplmental feedi~g are expressed in
(-'CFA (local currency) and ~1 is equivalent to 4CO eFA.
r; u t r i en t Re 9u ire men t s 10 r Gob r a Ze b u C0\\" S
7he nutrient recommendations for Cobra Zebu cows are
presented in Appendix table A.1
through A.S.
They are tabu-
12ted on monthly basis by cowage-group to correspond to
~hysiological and economical conditions i~volving cycliccl
body demand in nutrients according to the reproductive
status ano performance, cnd ration decision making over
i~tervals greater than 1 day.
Requirements for open-dry
cows are shown in terms of dry matter, metabolizable energy
and di[estible protein along .Jith pregnancy and lactation

---

adjustments~
Continued growth rather than discrete weights,
3C d2ys time unit for economic decision making rather than 1
day,
pnysiological
ti~e intervals 2nd reflection of specific
breed under specific environment are some important ractors
'''hich cr;ar'acterize these recor.:r;;endations and \\/hich fH,C
failed to account for.
The recommendations for Cobra cows are less than those
repor~ed by helton (1979) for Brahman-cross cattle in
Florida.
This can be largely attributed to the differential
between the genetic growth potentials of these two types of
cattle and the effects of their specific onvironments.
Feeding StrateF.V Under Average Production YE:ar
Management System I
Optimal carrying caoaciLy.
The ranee carrying capacity
by cowage-class and for the cow herd is presented in table
5.1.
During the last seven ffionths of the dry season (i.e.,
January through July),
it takes 3.29 to 4.01 ha of grazing-
land to carry a single cow of age ranging from 2 to 12
years.
In all age classes,
phosphorus is the most con-
sLraining nutrient in periods I and 11 followed by
digestible protein (DP) and rr.etabolizable energy (f.iE).
For
a 3 year old cow for example, a total of 35.5~, 79.73 and
91.26 percent of the minimum amounts of Pare neeued to
supplement 3.64 ha of Grazingland during Feriods I , l l and
Ill,
respectively (t,o:ble 5.2).
Like'dise, 9.44 and 0.0
percent DP and NE,
respectively, are required in Period I,

---

Ta b1e 5.1.
Summary of CarryinG Capacity
(ha)
by Production Year*
Production
Individual cowage class
(years)**
year
2
3
'1
r"
:J
6
?
8-10
11-12
)12
Co\\,'
he r'd
Average
3.29
3.G'1
3.S2
3.92
3.96
3.99
4.01
4 .01
4.02
300.33
Hc:Jiniest
1.GO
1. TI
1.86
1.90
1 .92
1.94
1 .94
1.95
1.95
145.70
Driest
'1.75
5.25
5.51
~.65
5.72
5. '/5
5.78
5.79
5.'19
433.13
--...:J
'.11
* Forage quality ai' the average year
is used for
both the
rainiest and driest yenrs.
**Cnlculations are based on maximum dry matter. requirement (i.e.,
3% of body wt/day).

---

Ta b le ).::::-.
11 u t r i e n t
Uc l' i c i t
coLS
P (, [' C e n t iJ g E.' 0 i' f':; i n i mu m I: E' qui reI r. e n t
l' 0 r
L h e
Vd r i 0 u ~ 1\\ [ e
CIa s s e S
[J u r i n e t h e
i\\ vel' (j g e
Pro cl u c t ion
Yea r
~gE.' classes (years)
CO\\'/
Period
r:utrients
2
3
4
~
b
'7
(\\-10
11-12
>12
he I'd
DP
10.57
9.44
il .5 j
3.21
4.19
6.~7
G.07
? .1 El
'( • <1:'>
12.4'(
1
( J H)
i·i1~
11 . '!C'
u
0
()
0
(j
(>
()
0
1'f .9)
p
~) 7 . GH
3~.53
1)).(;2.
4 U. 48
5:5.26
53.US;
54.2)
53.01
~..I) . ~)O
3'( . G5
UP
~5.54
<15.10
1G.ljO
4.30
0
()
(j
0
0
(:
--;c
r-.
11 (AJ)
[,lE
1 3 . t) 2.
8.'16
).52
1 .00
0.03
0.29
0.44
0.51
0.53
1 '( . U4
P
u3.93
79. '("j
'(1 .40
67.32
6'(.6'3
6'( • 51
6'i.3'(
6'( • jb
G'(.::;'G
)() . 7 i~
OP
96.0
96.6G 100
100
.
97.36
93.48
90.99
92.36
91 . r. '(
90.44
III (J)
I,) t:
)2.1,8
36.94
:J 4 . 2. 4
32. (;5
31 .25
31.38
2~)' 10
51.~·5
) 1 .20
::'~.OEJ
P
91 .21
91.26
<)2.45
92.18
91 .22
8S.3?
88.65
ElS.24
H<J.02
87.63

---

~ I r,
I
I
45.18 cnd 8.7t percent in P~riod 11, 96.66 ana 36.94 percent
ir. Period I l l .
'll,e
carrying capaci ty of the grazing land for 10C-cow
herd is esti~ated at 3CC.33 ha (table 5.1).
To ~ee t
the'
herd ~inimum require~ents the natural pastures need to be
supplemented with 37.65, 12.47 and 17.95 percent of ~he
total minimum required amoun~s of P,
DP and hE,
re~pEc-
tively,
in Period I, 50.78, 0 and 17.04 percent in Period
11, e7.63, 98.4~ and 33.08 percent in Period Ill.
Dry
matter and Ca are not limiting factors.
Es~entially, the
inadequacy of the forage to satisfy energy,
protein and
phosphorus requirements is permanent and increases 2S the
dry s~ason proceeds.
Optimal supDlemen~al feed costs and activities.
The
optimal solution of feed suppleffients is shown in Appendix
table B.1.
The total cost of supplemental feedin~ 100-co~
herd on native range from January through July amounts to
651)08.79 FCFA and the average cost per kg of calf weaned is
estimated at 113.25 FCFA (table 5.3).
The average supple-
ffiental feed cos~s ~er cow per day are estimated at 13.62,
33.49 and 75.75 FCF,\\ ~:or Period I,
11 and Ill,
respectively
(table 0-1).
Least cost supplemental feeds consist of
sorghum straw, millet straw and urea in Period I,
brewer's
dried grains, millet straw and cottonsceds in Period 11,
cottonseeds and groundnut ~eal in Period I l l .
These feed
i r. g red i en t s Cl r e e it!: P r £ 00 ci en erg y sou r c e s (c ere a 1 s t r a 'vi s )
or protein source (ure~) or tcth energy 2nd protein sources

---

7(;
,brewer's dried grains, cottonseeds ane groundnut meal) as
illustr2tec: in table 4.4.
r~'he high use oi grouncnut r.leal
in
July reflects the scope of protein and en€rgy
oeficienci2s
i nth Cl t
m0 n "t 1'; •
f'L3nager::ent System 11,
II I and IV
The optimal solutions are given in Appendix "tables B.2,
B.3 and 8.4.
The least costs of supplemental feeding 100-
cow herd are esti~ated at 558509.10, 466425.27 and 381770.06
FCA for System 11,
III and IV, respectively.
The manager of
Dahra research station will save 92799.G9, 184883.52 2nd
2695j8.73 FCfA as he chooses to use System 11, III and IV,
respectively,
instead of System I.
His feed cost per kg of
calf weaned will amcunt to 97.19, 81.10 ane 66.38 FCFA,
respectively (table 5.)).
The decreases in his feed cost
per kg ef calf wEaned 2mount to 14.18, 28.3C and 41.38
percent as he favors systems 11,
III and IV, respectively,
over system I.
Under the real conditions of Dahra, animals'
full requirements are never met during the long dry season
because of limited capital and forage resources aggravated
by the high cost of supplerr:ental feeds.
The managEr is
likely to prefer one of "these alternative systems over
System 1.
Further,
it is technically recommendec,
under
very limited forage
resource conditions, to "punisr." to c:
certain tolerable degree pregnant cows in order 1:0 save feed
resources for the lactation period.
Cows that are
11 pun ish e d"
d u r in g. the lactation period will not rebreed
curing the subsequent trE:'eding secson.
Likewise,
cows too

---

79
1able 5.3.
Optimal
Avc!'Z;.ge
Cos"'C (lo'CFA) Pe, !<G 01 (;Cdl'
\\.:een€G
f']anagemen t Systems
(% of minimum nutrient requirEments)
,,'
1°
Forage
I
11
III
IV
Year
improvement
(100)
(95)
(90)
(85)
AVera[E
0
113.25
97.11
u1 .10
66.38
kainies"'C
10
106.10
20
61.50
:>0.62
40.5U
4G.37
30
1\\('.60
45.4e
4:5.35
41.23
D,iest
-2C
176.88
150.84
12b. T5

---

8e
severely "punished" dcring th9 pregnancy will not give birth
"to vidble cwives and will not rebreed Qurine: the subsequent
breedinr season.
No cetrimentel efiec"t on either the calf
or the dam is expected as the pregnant cow, at the end·of
pregnancy,
loses some weight which she regains curing the
lactation period.
Activities that enter the optimal solution in Period I1
are brewer's dried grains, millet straw and cottonseeds for
System II, brewer's dried grains and cottonseeds for System
Ill, and brewer's dried grains for Systec IV.
The same
activities were found at different combinations in ~yste~: I.
Feeding Strategy Under the Rainiest Year
~anagement System I
Optimal carrying c2Dacity.
The optimal area of
grazingland required to raise an individual cow in each age-
group assuming that forage quality remains the S2~e as in
the average production yea: varies from 1.60 for 2 year oles
to 1.95 for cows older than 10 years of age (table 5.1).
Under the same conditions, 145.70 hectares will be needed to
carry 2 1GO-cow herd during the last seven months of dry
season.
To meet the herd requirements,
the native range
needs to be supplemented with 40.52, 19.00 and 35.G4 pe~cent
of the minimum required amounts of OP, ME and P,
respec-
tively,
in Period I, 32.55, 20.22 ana 64.15 percent in
Perioo 11 2nd 100, 33.41 and 88.66 percent in Perioa III
(table 5.4).
These nutdent cefici"ts are t1igher than those
obtained for the ~vera£e production year.
The reason for

---

81
'latle 5.4.
Nutrient Geiicit as Percent8ge 01 hinimum
P.equiremen~ [or the Driest and Rainies~
Production Yec:rs
Driest
Rainiesl:
Period
Nutrients
year
year
DP
0
40.)2
I
( J~n
r·jE
17.20
19.00
P
39. '(0
35.64
OF
15.70
32.55
11
(AJ)
ME
15.50
20.22
P
44.32
64.15
OP
79.72
100.00
IT... -1
( J )
['lE
29.11
33.41
P
75.22
88.66

---

82
this is tha~ as the dry matter availability increases and
the forc:.r,e quality rem2ins the same,
the minimuP.l Dt-: int2ke
rcquire~ent is quickly satisfied o~ iewer hectar€s
of lund
leaving grea~er amount of nutrien~ deficits.
As the forage qU2li~y is increased by 10, 20 and jG
percent to represent possible incre2ses in nutrier.t values
for the rainiest year,
the optimcll carrying capacity of the
native ranee for the 1CO-cow herd remains const2nt and is
equ21 to 145.69 hectares.
However,
the percent~ges of the
minimum requirements of P,
UP and ME th3~ are needed as
supplments decreaS2 significantly (table 5.5).
Optimal supplemental feed activities and costs.
Appendix ~ables 8.5, 8.6 and 8.7 shol;/' "the summcHies of
optimal supplemental feeds used and costs incurred.
The
least costs amount to 0,332.73, 69794.37 onc 58634.13 rCFA
for Period I
when 1C, 20 and 30 percent increase in forage
quality are assumed.
These costs are 2307,5.17,
102332.35
and 49952.02 FCfA,
respectively,
in Period 11 and 227276.43,
144342.39 and 136109.29 FCFA in Period Ill.
In all cases,
July supplementation is, always, more expensive than the
supplmentation of any period as indicated by the averaee
cost per cow per day.
The average costs per kg of calf wear.ea were estimated
2.t 106.10, 61-5G and 4'(.60 FCF'A Jor 10, 20 and 30 percent
increa~e in forc::ge quality,
respec~ively (table 5.3).
The
manager will expect ~o save substantial amounts of money 2S
the f 0 [' CJ e; e q u<3 1i t Y i ne r E:' a se S .

---

lable 5.5.
Nutrient 8eficit as Percentage of ~inimu~
Requirement for the R3i~iest Year
Percent Increase in Forage Quality
of Averaee Production Ye~: r s
Period
Uutrients
10
20
:;0
p
32.08
28.93
2J.91
I ( J j.; )
DP
30.07
25.99
21 .83
hE
10.87
2. r/5
0
P
59.02
54.0b
49.22
11
(AJ)
GP
29.33
26.11
22.88
ME
13.23
6.24
c
P
73.68
67.78
62.40
III ( J )
DP
88.04
86.54
55.05
i"! r::
26.76
20.10
13.44

---

84
Ac~ivities ~h2t enter the solution are brewer's dried
g r a ins, mill e t
s t r 2 vi,
co v: ple' a s t r 2. \\i,
U rea.
cc"t ton s e t= Cl S ,
ET 0 un d r~ u ~ f!I e Cl 1 and
r ice po 1 ish i nG and rr. i dc.: s .
Gr 0 un d r. u t cri e a 1
app~ars in Period
III in 211 cases.
Manogement System 11
Recall that under this system only 95 percent of the
minimum nutrient requirements in Period 11 are satisfied.
Appendix tables B.8 and B.9 summarize optimal feed
activities and lEast costs.
The costs of supplementing 100-cow herd ere 260209.Ge
and 233785.54 FCFA for foragE quality increases of 2C and 30
percent,
respectively.
Average supplemental costs per kg of
calf weaned were 50.62 and 45.48 FCFA;
respectively.
Average supplemental feed costs per cow per day amount to
7.75 2r.ci 6.51 FCFA Period I, 5.11 and 4.33 ["CFA for Period
11, 48.11 2nd 45.36 FCfA for PeriOd III in c~ses of 20 ar.G
30 percent increases in forage quality,
respectively.
The
manager will al\\~ays expect to incur higher supplemental feed
cost in July as compared to the other periods.
His feed
costs per kg of calf weaned are cut down by 5.14 fCfA as
forage quality improves from 20 to 30 perc~nt.
Decreases in
the same costs amount to 17.77 and 4.45 percent as he favors
System 11 over Sys~Em 1 in cases of 20 and jC oercent
increases in forage q~21ity, respectively.
Activities ~hat enter the optimal solution are brewer's
driEd grains, cowpea straw,
urea, groundnut meal,
rice
polishinG and midcs.
Urea ~ppears in every perioc, an

---

indica~ion of perm~nent protein deficiency even durin[ ~he
rainies~ ye3r.
Lxcept for the cowpea stra~, all the above
activities are found in July supplementation which is
characterized by important amcunts 01' trewerls eriea grains
and groundnut meal.
These two ingredien~s have rela~ively
high concentrations of both protein and energy.
Manaeement System III
Under this system,
it is assumed that ~rle manager could
meet only 90 percent cf the minimum nutrient requirements in
Period 11.
The optim21 supplemental feed costs and
activities are presented in Appendix table 8.10 and b.11.
Tr.e optimal feed costs incurred frcm January through
July are 249298.53 and 222874.39 FCFA ,as 20 and 30 percent
increases in forage quality occur,
respectively.
In the
same order, average supplemental feed costs per kg of calf
weaned amount to 48.50 and 43.35 FCFA (table 5.3) while the
average feed costs per cow and per day fer Period 11 are
3.90 and 3.12 FeFA.
More returns should be expected in this
system than in System I and 11.
with a 20 percent increase
in forage quality,
the manager's feed costs per kg of calf
weaned drop 21.21 and 8.92 percent as he favors System III
over Systems I cJnd 11,
respectively.
As forat;e qUCllity
increases 30 percent,
these costs drop 8.92 and 4.68 percent
'.... hen Systems I 2nd IT are replaced by System Ill,
respec~ively.
lhe least cost ration is mace up of brewer's dried
grains, COWP£2 strClw,
urea,
groundnut meal,
rice polishing

---

'.-
and micds.
As in Syst~m 11, urea enters the solu~ion in
e .J c hot' the t r. r e e fee- din g per i 0 d s \\0, 11 i 112 t rev: to:' r I s c: r i e d
[rains and [rcundnut ~(21 are used in Period Ill.
i';anageO'ent System IV
Uncer ~ystem IV, only 85 percent of the f:Jinimurll
nutrient requirements are met.
Appendix tables B.12 and
2.13 show the optimal feed costs and activities.
'i'he costs of supplementing 1CO-cow herd from January
through July are estimated a~ 238386.06 and 211961.88 Fe FA
for 20 and 30 percent increases in forage quality,
respec-
tively.
In the same order, costs per cow per day in Period
I I
are 2. 69 and 1. 91
f' CF J\\ .J nd cos t s per kg 0 f
c 2.1 f
vi e ant.' d
estimated at 4G.3r and 41.23 FCFA (t~ble 5.3).
For 20
percent increase in forage quality,
the latter costs drop
24.67, 8.39 and 4.39 percent when System IV is fevored over
~ysterrls I,
Il anc Ill,
respectively.
The respec~ive de-
creases in the same costs,
when forage quality is increased
30 percent are 13.32, 9.j4 and 4.89 peroent.
orewer's dried grains, cowpea straw,
urea, £roundnut
meal,
rice polishing ar:d miads are the activities in the
optimal solution.
Urea,
brewer's dried grains and groundnut
meal were used as in System 11 and Ill.
Feedin?, Strotefv Under the Driest Year
M2nagem~nt System I
In this section, only the optimal carrying capacities
of the native range 2ssu~ing constant forage quality (i.e.,
S D [;1 e
qu;j lit Y i.l sin a '/ ere: [ (' pro c! ~ c t ion yea r) are d i se us sed

---

87
(table 5.1).
the nutrient ~0ficits ~o be met by supplements
are presE~~ed in tDble 5.4.
hn area of 4)j.13 hect2res 2re
neecied to raise 100-co": herd from Jem.:ary through July wittl
~Elicits of 39.70, C.G 2nd 17.2 percen~ 01 ~he ~inimum .
requirE"d amounts of P,
Cl? 2nd ['1£,
respectively,
in Period
I.
In Period 11, the deficits are 44.32, 15.7 and 15.5
percent of the minimum required amounts of P,
DP and ME,
respectively,
while in Period III they are 75.22, 79.72 and
2 9 . 1 1 per c e n t,
res pE: c t i vel y .
Vi i t h sup pIe fil e [l tat ion,
4. '( 5 to
5.79 hectares are needed to raise a cow of age rangin~ from
2 to 12 years (~2ble 5.1).
t·l a nag e men t
SYs t ems I I,
I I I,
I V
20% Decrease in ror2~e Cualitv
Optimal supplemental feed activities and cos~s under
the conditions of 20 percent decrease in forage quality are
discussed for ~hese systems.
Surr.maries of these activities
and costs are shown in Appendix tables 5.14,
B.15 ana E.16.
The total cos~s e1 supplemental fceding 100-cow herd
are estimated at 811(~29.12, 692336.62 and 5G1u46.53 FCFA ior
System 11,
111 and IV,
respectively.
In the same order,
average costs per kg cf calf weaned are 176.88, 150.84 and
126.73 FCFA (table 5.3) while averabc costs per cow per day
arr.ount to 34.39 FCFA for Period I, 30.55, 17.27 and 4.9'( for
Period 11 anci 75.75 i'-or Period Ill.
Under these conditions,
the man2ger will
incur more supplemental feeding costs than
i n any cas e. co v ere din L his s t ud Y.
His low est fee d cos t
per
kg of calf we~~ed (17G.U8 ~CFA) is 13.4U and 20.63 FCFA

---

hiGher tfJ2n the higl1o,51: costs incurreo during the average
and rainiest years,
respectively.
This cost is exp~cted to
s h0 v! to' ven rn 0 r e i ne r P. ,-, S e sin Cd S e s 0 f
m0 re t to: 8 n 2 C: ~ e r C c n t
drop in forage quality.
Further,
it seemed unlikely that he
will ever improve his spending in July if h~ meets the full
nutrient requirements.
Activities in the optimal solution are brewer's dried
grains,
sorghum straw, cottonseeds, cane molasses and
groundnut meal in System 11 and Ill,
brewer's dried [rains,
cottonseeds and groundnut me~l in System IV.
The use of
cane molasses indicates high energy demand.
High amounts of
groundnut meal and tolerable amounts of cottonseeds are
always fed in PerioG III (July) where· demands in energy and
protein are maximum.

---

CHAPTER V
SUMMARY AND CONCLUSIONS
The firm considered in this study was the Livestock
Research Center of D~hra, a single cow-calf production unit
of S90C hectares of owned land whose objective was to deter-
mine nutrient requireG:en~s of Cobra Zebu cattle under the
conditions of the centEr ~nd to develop guidelines as to how
to combine economically the range and supplemental feed
resources and still satisfy the cow herd nutrient require-
mentsduring the last 7 montts of the dry season.
Linear
programming was used to determine the optimuQ feeding
strategy for Cobra Zebu cow herd.
In the analysis,
~stimates of carrying capacity of the
rangE were obt2ined uncer the conditions of ~he &verage,
rainiest and driest production years.
Least cos~ rations
were ob~ained for rnanagellient systems where 1UC, 95, 90 and
es percent of minimum r2quirements were met.
This was
designed to reflect feal conditions of feed resource scar-
city under whicn the manager can never satisfy ~he full
rEquir~men~s.
ThE docision to" meet only a fraction of these
requirements prevailed only during the last quarter of the
pregnancy.
Forage resources were used to the maximum and
the" deficit was met by feeding supplements.
The minimum and
89

---

,:'
,,.
maximum daily dry matter intakes were set to 2.5 and 3.00
percent of body weight,
respectively.
7he nutrient recommenda~ions obtained using ~he growth
curve 01 Cobra Zeou I'elr.ales are specific to ~hese 2nimal.s
under the conditions of Dahra research station.
Require-
mEn~s for open-dry cows arE expressed in terms of dry
matter, metabolizable energy and digestible protein.
Adjustments for pregnancy and lactation are also madE:.
Thirty days rather t;;an 1 day is the ~ime uni t for bio-
econo~ic decision making.
In other words,
requirements 2re
on monthly basis beginning from first mon~h to 12 months
after calving and by age of the cows to account for pnysio-
logical factors afiecting tody dc:mond' in nutrients.
The optimal gro=ing 2reas that can be utilized by 100-
cow herd were 300.33,
145.70 and 433.13 hectares during ~he
average production year (vl1th 1150 kg of dry mat~er per ha
per annum), rainiest year (~ith 2500 kg of dry matter per ha
per annum) and driest year (with 762 kg of cry matter per ha
per annum).
The highest carrying capacities for an indivi-
dual cow in a given age-group were obtained for 11
to 12
age-croup and varied from 1.95 ha in the rainiest year tc
5.79 ha in the drie~t year.
The lowest carrying capacity
(1.GC ha) was ct~aincd for 2 year cId cows in the rainiest
year.
Except for July,
p~osphorus was the DOS~ limiting
nutrient in the pastures followed by protein and energy.
In
J u 1Y 0 i
the 2. ve r 3 g e p :' 0 c: uC \\: ion yea r, de f i c its 0 f ph c s P11 0 r us,
dit:estible pr'o1:ein 2rl(~ l:ictaboliz2.ble E:neq:;y expressed 3S

---

percent of minimum requiremEn~s of 1GO-cow herd were 8'i.b3,
S~.44 and '3.Ce, respectively.
Overall,
"tel.::' ciefici"ts tenci
to be hi£h~r ~uring the rainiest YCGr th2n in tte driest
yeor.
Hi[her feed costs p~r kg of c~lf wea~Ed will be
expected during the driest year with 20 percent decrease in
forage quality and the lowest during the rainies"t year with
30 percent increase in for~ge quality.
Within years,
the
manager will expect substantial decreases in the cost per k[
of calf weaned as he chooses to meet only fractions of the
minimum requirements.
he will also expect his fEeding cost
to increase from the first period (January-April)
to "the
third period (July) of the dry season:for all
production
years and all systems.
'1. r. e
p rim 2 r y sup pIe men tal fee d sin the sol u"t ion 5 we r e
brewer's dried grains, groundnut meal,
cottonseeds,
urea,
sorghu~ and millet str2w 2nd cane molasses.
Ingredients
with high concentrations in both protein and energy were
predominantly used in July.
Limitations
Although 2 firm
level approach is used in this study,
certain limitations should be taken into consideration while
extending the results.
The solutions to the analysis of various management
alternatives are sub~~ct to input (feed ingredients) costs,
dry matter proauction 2nd forage quality estimates.

---

92
Results,
thereiore, are applicable only tor the levels of
res 0 ur c e.s cor. oS i ci e [' e G 'y.' i t L'i n s pe c i i i e a p r ice I eve 1 ~ •
~ne supplemEn~EI
ie~d price variations,
the calving and
weaning rates of Gobrn Zetu during the driest and rainies~
Y~crs, the chanee in forage quantity and quality betweer. and
within years are not knowr. with certainty.
Thus the
assumption that prices cno input levels are known wi~h
certainty is unlikely to hold.
The nutrient simulation model,
used in this s~udy,
failea ~o account for phosphorus and calcium requirements.
Phosphorus is the mcj~r li~itine nutrient in sahelian native
pastures.
National Research Council .recommendations for
both these nutrients were,
therefore, adjusted and used in
the anc:lyses.
Futhermore, due to the extremely 10'..' con'tent
of the phosphorus in forage it was impossible to satisfy the
requiremEf'lts of ~his nutrient Hi'thout inflc:tinr; 'tfle level 01
calcium in the diet.
Least cost analyses,
therefore, were
performed ... ith the assumption that phosphorus oeiici~ W2S
met.
This can be misleading.
The measure of cost per cow and per day did not take
into account the weight differences &nd thus the requirement
differentials between cowage-classes.
The comparison of
the costs of supplement~l ieeding between periods could havE
been mere efficien~ if this limitation had been removed.
Hesults of this ~3tudy provide ~ormative anS.iers to the
cornpl~x problem faced by tr.e cow-calf mc1nager in !.jar-Ire:;
Hesearcr\\ Center.
Unccr
this cenui tion,
his only objectivE:

---

c, '-'
7.-1
is "LO rdnifiJize the cost el' feeding suppI2r[,en-::s dur'ing l:ne
last seven mentils of dry S2asor..
The cour~es 01 ~c-::ion
o L! t I i n E- d by thE S tUG Y ~; rei: r. 0 sew h i c Cl he 0 u[; r: t
tot:.:: kE- •
I n
other ""'orcs,
linear progrclr.:r.1ir'b cescribes (;ondition~ 2S ·tf~ey
ou~ht to be rather thGn as they exist.
Cenclusions dr2.:n
from the no'sul ts 01 this stUdy [;lust consider these
limitations.
RecommendQtions and Further Research
The least cost medel exposed the }~ey limitinr, nutrients
in the native range 2nd which are increasingly Ceficient as
the dry season proceeds.
Mineral mix containing adequate
levels of phosphorus ShOU1G at least be mace available to
the cows in July.
f->t:o spho rus de fic ie-ncy is a ma jo r
ca use 01
reproducl:ive failure.
There are relal:ively nigh
concentrations of calcium in the natural pastures.
Care
must be exercised to sustain 2:1 or 1:1
ratio of Ca:P in the
diet.
Protein supplementation is essEntial ior' 2
proper
functioning of the rU~2n micro-organisms and for a proper
utilization of the available dried pa~l:ures which can supply
energy curing the dry season.
Urea and cane mo12sses should be effective in providing
protein and energy,
r~spectively.
~he legume and cereal
SLraws ore inexpensive 2nd should be used as energy
sources.
To avoid "July crisis," bEddnced diet sr.ould be
prOViG2C to thE COld:::' l.C::;in[ by-products wi th relatively nigh
(;oncer."t~'aLions in boU: c·ne:'f:~Y 3nu protS'ir..

---

Cl "
.J'T
InSOlEr as it is possible,
pr~gr.ant co~s should le
811cwec <:0 lose SOfl:e .....'cifl,\\: a~ the (:nd of prc[Jnancy by
l' e 2' Gin b a 1 r 2 C 1: ion 0 i
tr~ ere c; u i r to:' ci a El 0 U n t S 0 f
nut r i en 1: S •
~evere or prolongea undernourishment durin[, pregnC:T:cy Idll
hurt "the fetus and the cam but moderate undernourishment is
harmless and will help cut feed costs and save feec
resources for July ~upplementation.
The
stucy of ingredients'
price fluctuations within and
between years should be under"taken.
A research methodology should be developed a"t once 1:0
determine,
over years,
the quan"tity and quality of natural
pastures produced in Dahr2 research center.
The study of
risk associated with the production of these rainfed
pas1:ures and the mea~s to minimize that risk should be
undertaKen.
There can be no steady production of Gobra
Zebu, no positive returns "to investment if the properties of
the native range are unknown.
Finally, a gOGe d~ta record system should be developed
to facilitate the study cf "the reproductive performance of
Cobra Lebu.

---

;\\PPU;CIX A
f.:l;r; Th LY AVr: lU, CE t! U'l. HIE NT HEQU I RH: E1,'1 ~,
H.ik CUBRA ZlbU CC.i~i S IU Dj\\HRA RJ:.;SEM~Ch
CU;'l'U(
where
1.
~ge refers to agE in years of the animal as of
calving season.
2.
r;onth after c31ving is the month all:er calving
season,
re[or~less of whether or not ~he cow
produced 3 cal.!..
).
lA: = i.:gs 01.' dry 1712tt'er,
i'! E = l< c e. 1 0 I' in e t 3 b 0 1 i z a b 1 e
en erg y, 2.no
OP = h[s 01 Gigestible protein.
;';curcE:':
[';elt:on (19'/S!)

---

t:on~hly AverClge i:utrier.t RelJuir'ements Jor Gobr2
~etJu CO',,::;
ir. [);;hra,
~;enegal:
/1[12
=
2 YC'ars .

---

'istle !,. 2.
r'lonti:ly
Aver2ge i:utrient Eequirer.:ents l'or Goor2
LE"=bu (o',:s
in Cahr2,
~enegal:
AGe
= ~ YeClrs
fvionth
Requirements
Adjus1:ments
for:
Cl .r'te r
Open, Drv Co\\.!
Lactation
l-Tegndncy
calving
Lv!
r.j£
OP
ML
DP
~;(
1
210.16
55.3.<]1
5.88
218.6b
2.20
c.ca
2
211.93
.355.02
5.93
221 .68
~. 4'(
O.OC
7
.J
213.60
356.G6
5. ':)/:;
215.19
8.25
O.QC
4
215. F~
557.05
6.U2
2C2.56
7.69
1 . US
5
216.69
357.95
6.06
188.38
6.95
3.22
b
218.11
;~t.:.86
6.10
·175.41
(;.22
S.4c
7
219.45
3j9.G9
6. 14
163.13
5.53
o
::')
.-/ • ..J'-
8
220.73
-=:.60.48
( . 18
0
()
1').84
c-'
. /
221.93
.:: c' 1 . 22
6.21
0
0
26.';14
10
22).07
3G 1 .92
b.24
U
C
4':>.80
11
224.15
362.51:3
C.27
0
0
77.136
12
225.17
303.20
6.30
0
c
1)2.38

---

Table A.j.
Monthly Average ~utrient Requirements for Cobra
Zebu Co~s in Dahra, Senegal:
ACE
= 4 Years
i'ionth
Requirements
Adjustments for:
after
Open, Drv Cow
Lac ta tion
Pregnancy
calving
Ot·j
filE
OP
t·lE
LiP
f·;E
1
226.14
363.79
6.33
221.60
8.81
O.GO
2
227.06
364.34
6.35
224.44
9.02
0.00
)
227.92
364.87
6.38
217.79
e.72
c.oo
4
228.'14
)65.36
6.40
205.32
c.OG
1. 96
5
229.52
365.83
6.42
190.'10
7.23
3.33
G
23(;.26
36G.28
6.44
177.60
b.42
5.b7
7
230.95
306.70
6.46
165. 17
5. 71
9.65
8
231;61
367.09
6.48
0
0
16.41
9
232.23
367.47
6.50
0
C
2~( .9C
10
232.82
367.e2
6.51
0
C
4'( . 43
11
233.38
368.16
6.53
0
0
80.64
12
233.91
368.47
6.54
0
0
137.10

---

99
TablE A.4.
riont:hly Average Nutrient Hequirements fcr Cobra
Zebu Co~s in Dahra, Senegal:
Age = ~ Ye3r5
i'lon th
Requirements
AdjL:s"tments for:
after
Open, Dry COy:
Lactation
Pregnancy
calving
DI'-1
r·1E
OP
HE
DP
t!jE
1
234.41
368.'1
6.56
223.07
9.12
0.00
')
L..
234.89
369.06
6.57
225.83
9.30
C.CO
3
235.33
j69.33
6.58
219.11
8.96
0.00
4
235.76
369.58
6.60
206.56
2.26
1 .9S
5
236.1'6
309.82
6.61
191.Se
'( • )0
3.39
6
236.54
370.05
6.62
178.'12
0.52
5. '1'1
7
236.90
37C.26
6.G3
166.20
5.80
9.62
0
v
237:24
370.47
G.64
0
0
1G.'(O
9
23'/.56
370.66
6.65
0
0
28.39
10
237.87
370.C4
6.66
0
0
4tL 27
11
2;'8.16
371 .02
6.66
0
0
82.C7
12
23cL 43
371 .18
6.6?
0
0
139.53

---

t~·:::~·~
-
;;w .. '~:.
100
Table 1\\.5.
L 0 nth 1Y j\\ v e r (J ~ e L u t r i e n t
Re q t..: ire men t s i 0 r
c.: 0 b r 2-
LI: b t..: Co \\1 ~; i 11 [; a h r c"
~ e n e £ a 1 :
AC~ = to Ye G r s
f~onth
Requirements
Adjt..:stmen::s for:
after
Open,
Dry CO\\'/
Lactation
Prcpnancy
calving
Cf'l
l·~ t.:
DP
t..IE
OP
[,,; ;;
,-
1
238.69
371.34
6.08
223.83
9.28
c.oo
2
236.94
)'(1.43
b.09
226.55
S.45
o.oc
J
239.17
)'(1 .62
6.69
219.78
~1. 08
0.00
4
2393.9
371 . cl)
6.70
207.21
d.jG
2.01
5
239.60
371.88
6.70
192.48
7.45
3.42
C
239.7S
3('2.GU
6.71
179.29
6.5 C
5.82
(
'(
239.98
372.11
6.71
166.73
5.84
9.91
E
240.16
;',72.22
6.72
0
0
16.85
c./
240.32
2/2.32
6.72
0
0
2(3.64
1C
240.48
3~i2.L12
0.73
0
G
4u •c/O
11
240.63
372.51
G.73
0
0
e2.UO
12
240.77
Y? 2.59
6.74
0
0
140. cn

---

101
T<} b1e I,. \\:) .
h 0 n 1: h 1Y 1'-. vere gel': u t r i e n t
f{ e qui rem en t s
l' 0 r Gob r 2
Zebu Co~s in Lanra, Senegal:
Age = 'l Years
hon1:h
Requirer.1ents
Adjustments for:
a l'te r
Open,
Cry Co'.:
Lactation
PregnClncy
calving
01'1
1'1 E
DP
HE::
DP
i·;E
1
240.91
372.61J
6.74
224.23
9.37
c.oo
2
241.03
372. '/6
6.74
226.9:::
9.53
0.00
3
241 .15
372.£23
6.75
220. 14
9.15
O.OC
4
241.2'1
3'/2. <)0
G.75
207·54
8.41
2.02
c;
-'
241.37
372.97
6.75
192.81
7.49
3.44
-
tJ
241.42·
3Tj. C4
6.76
. 179.00
G.LC
5.1::5
241.57
373.10
e.76
167.C3
5.67
9.95
(
8
241.66
)'1) . 16
6.76
0
u
'16.92
9
241.75
j73.21
f~. 76
0
0
2t.77
10
241.83
37).2'1
G.77
C
0
48.92
11
241 .91
373.32
G.77
0
0
83.18
12
241.98
373.3'1
6.77
0
0
141 .42
,... ;" ~

---

1u2
T;: b1c: A. 7 •
1-"1 0 nth 1y
A vel' 2 g Eo I~ u t r i e nth: e qui r erne rn: .s i' 0 r Got r Ci
Z~bu COWS in 02hr~, Senegal:
Age = L-10 Ye2r~
fionth
Requirements
Adjusttile:lts for:
after
Open, Llry CO\\/
Lac 1:2. ti on
Frepnancy
celving
Dt-I
~1 t:
OP
r·; E:
Ui-'
[·iE
1
242.65
373.90
6.79
224.59
S.43
0.00
2
242.68
Y(). s·)
6.79
227.27
9.59
O.OC
3
242.71
373.97
6.79
220.48
9.20
0.00
4
242.74
374.00
6.79
207.8'1
S.45
2.03
5
242.77
374.04
6.79
193.12
7.52
3.45
G
242.80
374.07
6.7<,]
'179.S1
6.62
S.c7
-(
242.82
374.11
G.79
167.)1
5.8S
9.9')
8
242.85
374.14
6.79
0
0
10.9b
c./
242.87
374. '18
6.80
0
(;
2c.ce
10
242.89
)74.22
6.60
0
C
49. '/0
11
242.91
374.25
6.80
0
0
e3.48
12
242.93
374.29
6.80
0
0
141 .92

---

1U3
T~ble
A.b.
~.onthly Average t.utrient Requirements lor Cobra
LE b L!
eOI-' s i n
L"; Cl h ra,
Se nee a 1 :
ACe:=
11 - 1 2
Ye 2. r s
r\\lonth
Requirements
Adj us tmen ts for:
after
Open, Dry Cow
Lactation
Pregnancy
calvir,g
D[··j
t:jE
DP
El::
DP
LE"
1
243.11
374.34
6.eo
224.84
9.45
O.oc
2
24:5 . 12
374.34
0.80
227.33
<J.SO
u.oo
3
24:5 . 13
374.34
6.80
221 .01
Si.21
a.GC!
4
24:5 . 14
374.34
6.80
209. )1
u.46
2.03
Co
./
243.14
374.34
6.£30
195.61
'I . 53
).46
-
b
243.15
374.34
6.80
-183.33
6.S3
5.88
7
243.16
3{" 4.34
6.80
1?C.5
5. S'O
10.00
8
243.1'(
374.34
i).SO
C
C
17.00
9
24j.17
374.34
6.20
0
()
28·90
10
243.12
374.3i)
6.80
CJ
0
49.15
11
243.18
3/'4.34
6.eO
()
0
83.56
12
24:5 . 19
:::74. )4
6.80
0
0
142.CG

---

1G4
Table A.~.
~onthly Average hutrient Hequirements for Gobra
Zebu Co~s i~ Dahra,
~ene~2l:
Ag2 = >12 Years
f';onth
Hequirements
Adjustments for:
nl1:er
Open,
Dry Cow
Lactation
Pre~'n2ncy
calving
on
['·iE
ep
[viE
C,P
~,E
1
243.27
3'74.34
6.81
224.e4
9.45
0.00
2
243.2"7
374 . 34
6.81
227.))
9.61
u.uo
3
243.27
374.)4
6.81
221.01
::;.22
C.OC'
4
243.27
374.34
6.81
204.31
t.46
2.0)
5
243.27
374.34
6.81
195.61
7.53
3.46
6
243.2"7
374.~'54
6.81
'183.35
6.6)
~.e8
7
243.27
374.34
6.81
170.5
5.s)0
1U.OL:
C
243.27
3"74.34
G.81
C
0
17 .01
C)
243.27
3'74. :54
6.81
0
C
22.<)1
10
243.27
374.34
6.81
C
C
49.16
11
243.27
374.34
6.81
0
0
83.58
12
243. 2~f
j"f 4.34
6.81
0
0
142.10

---

APP£NDIX B
OPTIMAL SOLUTION OF SUPPLEMENtAL
FEEDING 100-CO~ HERD OF GOBRA ZEBU

---

'l'E.:ble
L.1.
tJpTir:l;'l1
Solution
Ol
~upplern(;nt51 l;\\:t:cing 1C'(1_CO\\/ fieI'd Uurir:b ilrl j'.Vu·c.I~i.C
IJro(1uction
Year
-
.sYSl:<.:r.1
I
(H;u/u uF f(i:;QUli;l:,i·:Li~'l'S ;d,L i·jLT)
P Eo I' i 0 <..i
1 (J I·: )
['0 I' io(i
r 1 (/I.J)
Pel'ioe
I I I
(J)
Activity
Level
(1~------Co5t (rCI"A)
Lev~l (kg)
Cost
(VCFA)
Level
(kg)~Cost (FCFi>.)
u I' e \\1 E: I' I 5
(j r i e d
[;rnins
2 , :JG(; • Cv
l)/I , CJOU • uU
~,o f'/~hur.j s t re W
'(,j:JJ.2)
Go,'i:J2.j2
r: i. 11 ~ i: s t I' cl \\;
i~ , ~ i~ 2 . ~ ~j
.;;:: , (,0 c.:) • 1 ,)
i ) , '1 2 ~) • j c.~
I L'(), <:/(i....>. 'jG
UI't?:J
<'; :) • ~) (5
1,b~~1.20
- '
c
COl: ton ::;:':::':0 S
2,v00.(;(j
'(U, 4GU. Clu
:;Lti • ~. /1
20, l'VG • J (
C'
Groundnut rTiC?81
) , (';(),~ .~)~'
?OG, 0'(0. Ob
'J.'ot3l
suppH·men-
tul fC0d cost
( fClo'P. )
'I ~2, :64 . ()L
.J()1,4~G.~u
2. ~ '/ , '2.'( lJ • I) ,:;
J\\ v t:. I' (;; Le
sup p 1 e -
III C rj 1- E: 1
.1" to: c· d
cos T.. / C 0 \\v / cJ a Y
«
( H.: 1"1\\ )
1:).02
:,,).41j
r/ ~.) . 'I ~,

---

'l2ble
B.2.
(jptir:~cll ~olution of Supplement.i1l [·'ceding 100-Co\\-.' IlercJ Durint( J\\n /'v,::r'l{:J'
Production
Year
-
~~y.stur. 11
(95~J C,F lU:C)UlRt;[';EN'l'~}
AI\\[~ l'][~'l')
l..leriod
I
(JI·j)
Period
11
(AJ)
!Jer'io(J
ill
(J)
P,ctivity
Level
(kg)
Co-st(l.·cVA)
Level
( kg)
Cost ( FCFA)
Level
(f<E;J Cost ( Fer/<.)
Ere.,er I S
dried
f-:rains
2 , :') GO • CO
G4 , QUO. (:Ye
:::;0 r gl1um
s t nH:
'/,))3.25
Uc,~/32.)2
r:. ill c:: t
s t r cHI
tj,5~2.29
32 , 023 . 1 /j
j,GGI).5u
~/ll, 1'(b.(j()
Urea
45.90
1,[)j9.2
CottonseccJs
2,OUC.OO
/0, 4GC. 0(1
5bLl. 91
20,606.5;
--"
~
Groundnut menl
3,G04.92
2C0,C'/C.OG
--,~
'i'otal
supplemen-
tal
ieed cost
(fCF'A)
122,59t1.oC
20u,Gjb.LG
2.// , 2'(0.4)
/;ve:rCJf,e supple-
mental
feed'
cos t / co v, / d 2 Y
(I'CrA)
1 j .l,Z
22; . 1 t3
'1').'/5

---

'l'c-lole
L::;.
(]ptir.lCil
:"-;olution
of :.)upplE:-menL:l1
Feedinf,
1UU-COh' Herd DurinG iHl Aver:::.ce
F'roduc1:ion
YCc)['
-
Sy~;tefll III (<jO~; OF HEQUIl~EI-iU!1'S I\\HE r-II:;T)
Period
1
(JI-I)
Period
11
(t,J)
f'criod
111
(J)
Activity
Level
(kg)
Cost
(FCFAJ
Level
(I~L)
Cost
(FCFAJ
Le vel
(1< g )
Cos t
(F' CF AY
E f e vi e r I s
d r j e d
g,faills
2 , ~)OO • 00
tJd , ()OCi • 00
~oC'ghum straw
7,)33.25
eu, '( 32. j2
(.; i l l e t
s t r a I-i
11,542.2Y
.:i? , 02 j . 'I t\\
UC'ea
45.98
1,U)Y.2
CO'ltonset:Cis
1 , 4 'J 1 . '/1
J:~ , :'>52 .94
584.91
2u,(;Ub.j'(
~
c
Croundr.ut OIedl
3,G04.92
2GG, V/O. oG
c;-;
Tot Cl 1 ::; u pp 1 e IfI t~ n -
tal
feed
cost
(FCFA)
122,5 Cj4.Gb
11b,SJ2.~4
22'{,22u.4)
AveC'agc
supple-
rr:'ent<31
feec
cost/cow/day
(FeF'!, )
1.-) . 62
12. y~)
,": L·
, .. I..:
, "'.). I ..J

---

Table
E.4.
Optimal Solution 01' Supplemental Feeding 100-CO\\-1 Herd DurinL! I\\n {ver'o£!e
Production
Ye8r -
System IV
(C5~~ OF HE()UIREC·ll::Crl'S fIR£:: r1ET)
Period I
(Jr·1)
Period
11
(AJ)
Pe r i od
I I 1
(J)
"
llC ti vi ty
Level
(kg)
Cost (FCrA)
Leve 1 ( kg)
Co'stl r'CFA)
Level
(kg)
Cost(FCFA;
13 r e \\,1 e r I s
d r i e d
[rains
1,246.01
51,897.[\\5
Sorghum str8w
'(,333.25
88,732.52
I"; ill e t
s t r a I,'
4,542.2~
32,023.14
Urea
45.90
1,839.20
Cottonseeds
5U4.S1
20 , 606 ..) '(
-'-
C
Groundnut meal
3,G04.92
206,670.0G
'-J.
Total
supplemen-
tal
feed
cost
(FCFA)
122,594.66
j1,bY?U5
22'1,2'(6.4)
Average supple-
mental
feed
cost/cow/day
(FCFA)
13.62
).54
'/5.'()
•

---

Table B.5.
Optimal ~olution of Supplemental r'eedinG 100-Co", Ilerd uurinf '.i.'he Huiniest
Production Year -
~ystem I
\\'lith 10 Percent Increase
in Forage QUc:l1ity
Period
I
(Jf.])
Period 11
(AJ)
Pe r i od I I I
(J)
ACt:ivity
Level
(kg)
Cost (FCFAl
Level
(kg)
Cosr--[F'CFA)
Leve 1 ( kg)
Cos t
(F'CF'A)
~re\\.,rer's dried
grains
2,500.00
G4,COO.OO
rH 11 e t
s t r C) ....
1 , r( 1 4 • 04
12,0E33.9[3
4,G86.E3?
9(j, j 15.17
Co VI p e 2
s t r a v,
j,jG5.00
'(2,695. '15
Urea
63.81
2,552.40
Cotton seeds
2,000.00
'(0,460.00
584.91
20,606. YI
--"
-,
Groundnut meal
3,604.92
206,6?0.06
o
~otal supplemen-
tal feed
cost
( F'CF';\\)
8?,332.13
2:jO,T75.1 r(
22'1,2'/(;.43
Average supple-
men ta 1 feed
cost/co .... /day
( FCF'/I )
CJ.70
25.64
'15.'r5

---

Table L.6.
Optimal ~olution oi' Supplem~:ntCJl Feeding 10U-Co~J Herd During The i:.:;iniEo.'st
Production Year -
System I
With 20 Percent Increase
in Forage Quality
Period
I
(JI,I)
Period
11
(AJ)
Pe r i od I I I
(J)
Activity
Level
(kg)
Cost (FCFA)
Level
(kg)
CostTFCFAl
Level
(kg)
Cost-rF'CF'A}
GreHer's dried
frains
CO\\oJ pea
s t ra \\oJ
U re~~
Cotton seeds
Gr 0 u n <.1 nut ([~ e8 I
[nee pol ishin8
& midds
Tot2l
supplemen-
t8l
feed
cos t
(FeFA)
69, '194 . )'(
102,3:;2.35
14i1,3t12.jt)
I\\verage
supple-
Iilen ta 1 feed
cost/cow/day
(FCFA)
'I 0 r( ~
11 • j '(
11 tJ • 11

---

TeJble 1.;.'(.
Optimal Solution of Supplemental
Feeding 100-Co'rl He['d [)urinl" The H3ir.il'sl:
Production Year - System
I
~.:ith 30 Percent 1ncrec:se in Forage QUcdity
Per iod
I
(Jl"j)
Period 11
(I\\J)
Pe [' i od
III
(J)
Activity
Level
(l<iT- cos1;-rrC-:-FA)
Level· (kg)
Cost---n'CFA-)
Level
(ktJ
Cos-t-1FCF]\\)
8l'ewer's dried
grains
1,023.33
4S, 2)'(.24
~2G.Ge
5,L05.0(,
Co yl pea s t r 2 \\v
4,215.5<)
57,11LL5:5
Urea
j'/ .139
1,515.60
1 r( • Wf
714.UU
2) .0'/
922.eo
Groundnut meat
2,25b.82
129,j83.4Si
->.
->
N
Total
supplemen-
tal
feed cost
(FCFA)
58,634.13
49.952.04
156,1CJ9.29
Average supple-
mental
feed
cos t / co 'vI / day
(FCFA)
G.51
.:
hh
././:>
Ij).jG
w

---

Table b.c;.
Optim<ll
Solution of Supplemental Feeding 10C-Co\\o, Hc·rd
During The H<iiniest
Production Year -
System 11
With 20 Percent Increase in forage Ouali~y
Per i 0 d
I
(J t·] )
Pe r i od
I I
(A J )
Pe r i od
111
( J )
Activity
Le vel
( kg )
Cos t
(F'CFJ\\ )
Level
(kgT-Cost(1·'Cr'A)
Level
(kg)
Cost
(fef'/\\)
Ere ~, e r I s d r i e d
r;rains
1,T(3.91
;'5,412.0')
c>,uI3G.uj
'(), ~02 . l;tj
Co\\o'pea
straw
5,01'/.'14
6'( , 990.3'1
Urea
45.10
1,8G4.00
1G.48
659.20
213.60
1,544.CJ(;
Groundnut meal
1 , 1 j 4 • 52
GS,042.03
I<ice polishing
-"
&
-"
midds
132.1313
3,1353.52
0!
Total
supplemen-
tn 1 feed cost
(FCFA)
69,794.3?
46,0'11.29
144,)112.j9
Average supple-
men to 1 feed
cost/COW/d8y
( fCf'A)
'I. '15
5.11
48.1"

---

Table D.9.
Optimal Solution of SupplcmentQl Feeding 10C-Cow llerd During the R&iniest
Production Year - System 11 With 30 Percent Increase in Forage Quality
Pe r i od I
(J I'·] )
Period 11 (AJ)
Pe r i od 11 1 (J)
Activity
Level (kg)
Cost O'CFA)
Level
(kgjCosttFCFA)
Level rkgr-cost O'CFII)
[rewer's dried
grcins
1,)03.21
j[~,4G2.17
226.Gb
),UOj.00
Cow pea straw
4,215.59
57,1111.53
Urea
37.G9
1,515.60
15.<)6
55e.40
25.0'/
922.t50
Groundnut meal
2,256.82
12Si,383.49
--'.
--'
...'
total supplemen-
tal feed cost
(FCFJ\\)
58,634.1)
39,040.57
156,109.29
Average supple-
mental feed
cos t! co,",'! day
(FCFA)
6.51
4.:;3
45.36
•

---

, I ,
TCible IJ.10.
Optimal Solution 01' ~upplemental Feeding 100-Cov: Herd Durine the I{ainiest
Pro due t ion Yea r
-
S y s t e m I 1 I
iH t h 20 Per c e n t I n c re use
in For Cl g e Qu 8 1 i t Y
Period
I
(JI·:)
Pe r i od
I I
(AJ)
Pe r i oc
III
(J)
t.ctivity
Level
\\kg~-Cost- (FCFA)
Level
(kg)
Cost (FeFAl
Level
(kg)
Cos-t-(FO"j\\.)
Ere ..... er I S
dried
~::,z,ins
CO\\lpea straw
Urea
Groundnut meal
Rice
polishing
& midds
Total
supplemen-
ta 1 feed
cost
( FeF A)
oY, '194 • Y/
35,160.22
14'1,342.39
f\\verage
supple-
rr:ental
feed
cost/cow/day
( Fe FJ\\ )
7.'15
).90
4EJ .11

---

Table B.11. Uptimal ~olution 01' Supplemented Feeding 100-Cow Herd During 'The Rainiest
Production Year - ~ystem III With 50 Percent Increase in ~'orage ~uality
Per'iod I
(JH)
Period 11 (AJ)
Period III (J)
Activity
Level' (kg )Cost -( f'Cf'A)
Level
(kg)
Cos t
(FCf'A)
Level U;£)
Cost (FCfA)
Urewerl~ dried
[rains
1,OOj.00
2'l , l2 'I . 36
226.60
5,euj.uo
Cowpea straw
4,21).:59
'( , 11 (j • 53
Urea
37.09
1 ,5 '15. bO
10.06
402.40
23. U'(
S:22 • t,O
Groundnut meal
2,256.B2
129,j/jj.4S
--"
--"
, -
c'
Total supplemen-
tal feed cost
(FCPA)
58,634.13
28,129.76
136,109.29
Average supple-
menta 1 feed
cost/cow/day
([-'CPA)
6.~1
:5 • 1 ~:
45.)6

---

'l'nble 1.).12. Optimal .solution of Supplemental Feeding 100-Cov/ Here [Juring 'i'ell:' Hainics"t
Production Year -
System IV With 20 Percent Increase
in forage ~udlity
Pe r i od
I
( J 1,1 )
Period
11
(i\\J)
f-'eriod
1I1
(J)
Activity
Level
(kg)
Cost tF'CFA-)
Level
(kg)
-Cost-O'C~'A)
Level
(kg) --Cost U'C157\\)
Ure\\ler l S dried
grains
Co'Wpea
straw
Ure3
Groundnut meal
Rice polishing
0.
midds
Total
supplemen-
ta 1 feed
cos t
(FCF'A)
69,794.37
24,21\\'(.'12
14L1,j42.)9
Average
supple-
menta 1 f'eed
cost/cow/day
(FeFi\\)
'1.'i5
2.69
,; /j • 1 1
•

---

Tab 1e B. 1 j. 0 pt i ma 1 Sol uti 0 n 0 f Sup pIe men tell Fee din g 100- Co 'rI Her d Du r i n g '1'I'J e H2 i n i c· s t
Production Year - ~ystem IV With 30 Percent Increase in Forage Quality
Per i 0 d I
(J Ivl )
Period 11 (AJ)
Pe r i od
1I I
(J)
lIe ti v i ty
Level (kg)
Cost (FCFA)
Level (kg)
Cost CFCFA-)
Level
(kEd -Cost-O~CF'I\\J
Brewer's dried
rrQins
GC,2.9j
16,')'/1.00
220.6u
),GCj.OCJ
Co\\.'pea straw
4,215.YJ
5'(,11£;'53
Urea
3?eC)
1,515.6
(;.16
246. ,t
;:.' j . 0'(
<.J2;':.eu
Groundnut meal
2, 25G. {52
'129,383.49
--"
--"
c:
Totul supplemen-
tal feed cost
(FCFA)
5U,63t\\.13
1'(,21"1.40
130,10C).2Si
Average supple-
mEntClI feed
cost/cow/dny
( FCFA)
b.51
1 .91
4~ • .:J6
G

---

TEl b 1e 13. 14. 0 P t i ma 1 Sol uti 0 n 0 f
Sup P 1em e n tal Fee din f, 100- Cow IJ e r d 0 u r i n t' '1' f1 e L; r i ~ s 1.
Production Year -
System 11 With 20 Percent Decrease
in Forage Quality
Period
1 (Jr"j)
Period
11 (AJ)
Pe r i od I I I
(J)
Activity
Level
( kg)
Cost -rF'CFA)
Level
(kg)
Cost- CFCFA)
Leve 1 (I.:g)
Cos i-(1'CF'A)
r~re\\,rerls driod
er·~ ins
G, se '( .64
108,(4).5iJ
2,500.00
64,000.00
SO!'ghurn straw
0.01
0.12
4,279.99
109,567.74
Cottonseeds
4,OOO.UO
140,920.00
2,000.00
70,460.00
5G4.~1
2C,60G.)7
C()ne molasses
823.4
30,959.84
-"
Cr'oundnut meal
),("Otl.92
2(,.,'6, V(O. OG
-"
'.n
10t~1 supplemen-
ta 1 feed
cos t
(FCFA)
j09,5b).70
2 r( 4 , 9e7 . 5£3
22'( , 2'(6.4:-j
Average
.supple-
mental
feed
cost/cow/day
( FCFi\\ )
;'4. YJ
)0.55
'I 'j • '15
..

---

Table L15.
Optimal ~)olution of ~upplelllentul Fcedin[; 100-Cow Herd (Juring 'H,e Lrie~t
l)roduction Ye8r -
~;ystem III \\iith 20 i-'ercent uecrense
in F'or3ge QUCility
Pe r i od
1 (J [1'1)
Period
11
(AJ)
Pe r i od
I 1 I
(J)
Activity
Level
(kg)
Cost-TFCFA)
Level
(l~g}--Cosf (f.'CI;'/d
Level
(kg)
Cost (FCFAl
13r0~.'er IS dr'ied
grains
GI SUr/ • Cll
16S,C~3.Sb
~,~oo.oo
Gtl,uuo.OO
Sorghum stravJ
0.01
0.12
127.99
3,27G.54
Cottonseeds
tl,OOO.OO
140,920.00
2,000.00
,!O,4GO.OO
~e4.91
20, GOG • )'/
C1\\ [~r·1
4 '/2. j
17,758.48
Crouncnu1: meal
3,G04.~2
206,6'10.00
-"
f\\.:
C
10tal
supplemen-
tnl
feed
cost
(FCFA)
309,563.7
155,495.02
22'( , 2'16. LLj
Average
supple-
mental
feed
cost/cow/day
( FeF'A)
3~ .3~
1 '/ • 2 r/
('5. '/ ~

---

Table J..L1G.
Op·timol Solution of Supplemented
Feeding 100-Cow Herd
LJuring The Driest
Prociuction Year
-
~ystEm IV Vlith 20 Percent Decrease in FOr28E: <,;:unlity
Period
I
(JI·;)
Pe r i od
I I
(AJ)
_ fJe r i od
11 I
(J)
Activity
Level
(kg)
CosC CFCFA)
Level
(kg)
Cost- (f.'CFA)
Leve 1 (kg)
Cost (Fe})\\)
Drewer1s dried
grains
6,587.66
168,644.10
Cottonseeds
4,000.00
140,920.00
1,271.74
44,803.4
se4.e4
20,605.91
Groundnut meal
3,605.00
2C6,6 r(t!.GL
---'0
(\\.;
Total
supplemen-
---'0
tal
feed cost
(FCFA)
'09,5G4.1
44,80).4
22'( , 278. 5G
Averace
supple-
menta 1 feed
cost/cow/duy
O'erA)
34.39
4.97
75. r{)

---

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---

122
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~&T/DIU/ESDA.,
\\.: 2 S h i ng ton,
0 C •

---

E1 CGhl\\P~l I CAL .sV.t,lCh
Koejo Pierre AbasS2 ~~s born January G, 195C, in Kouve,
Togo.
Ee attended "Cr.e ·~:eterir,Qrion
Sr.hcol of D8Kar
(Senegal) from 1969 to 1975.
He graduated with a DVh tegree
on April 15, 1975.
He worked as a research assistant and
Head of Division of Animal I~provement at the Agricultural
Research Center of Togo from 1975 thrcugh 19J7.
In 1978, he
entered the Graduate School of the University of Florida to
pursue his studies in both 2nimal science and focd and
resource economics.
f!e
received a Plj.D. degree from the
Animal Science Departmen~ at the Universi~y of florida on
April 28, 1984.
~r'·
," ,"

---

I certify that I have read this study and tha~ in my
opinion it conforms to acceptable standards of scholarly
presentation and is fully adequate,
in scope and quality,
as
a thesis for the degree of Master of Science.
Assistant Professor of Food
and Resource Economics
I
certify that I
have read this study and that in my
opinion it conforms to accept8ble standards of scholarly
presentation and is fully adequate,
in scope and quality, as
a thesis for the degree of Master of Science.
R0 n a 1d h.
vi a r d
Profe::;sor of Food and Resource
Economics
I
certify that I
have read this study and that in my
opinion it conforms to 2cc~ptable standards of scholarly
presentation and is fully adequate,
in scope and quality, 8S
a thesis for the degree of Ma ter of Science.
Science
L
This thesis was submitted to the Graduate Faculty of the
College of Agriculture and to the Graduate School, and was
accepted as partial fulfillment of the requirements for the
degree of Master of Science.
Decel.lber 1984
Dean,t901lege of A
culture
~ean for Graduate Studies and
Hesearch

---