TABLE OF CONTENTS
Certification…………………………………………………….……………….i
Dedication………..…………………………………………………………….ii
Acknowledgement…………………………………………………………….iii
List of Table…………………………………………………………………….iv
Abstract…………………………………………………………………………v
CHAPTER
ONE: INTRODUCTION
1.1
Objective of the Study……………………………………………………2
1.2
Problem Statement……………….……………………………………….2
1.3
Justification……………………………….………………………………3
CHAPTER
TWO: LITERATURE REVIEW
2.1 West
African Dwarf Goat Breeds………………………………………….4
2.2 Importance
of Goats…………………………………..……………………4
2.3 Indigenous
Breeds of Goats……………………………..………………….5
2.4 Environmental
Factors that Influence Economic Traits………… …………6
2.4.1 Birth
Weight…………………………………………………………..……6
2.4.2 Weaning Weight……………………………………………………..……..8
2.4.3
Litter Size…………..…………………………………………………….
9
2.5 The
Genetics of Economic Traits of Farm Animals……………… 10
2.6 Growth
and Reproductive Traits of West African Dwarf Goats…… 11
2.6.1
Growth……………………………………………………………….….…11
2.6.2 Body
Weight……………………………………………..………………. 12
2.6.3 Body Weight Gain….……………………………………………………. 13
2.7 Body
Measurement and Body Weight……………………………….
14
2.8 Genetic
Relationship between Traits………………………………
14
2.9 Genetic
Parameters for Birth Weight………………………………
17
2.9.1 Heritability…………………………………………………………..……..
17
CHAPTER
THREE: MATERIALS AND METHOD
3.1 Location
of the Study……………………………………………………. 18
3.2 Experimental
Animals……………………………………………………. 18
3.3 Housing
of the Animals………………………………………………….. 18
3.4 Experimental
Design…………………………………………………… 18
3.5 Management
of Experimental Animals………………………….…….18
3.6 Management
of Pregnant Does…………………………………….….. 19
3.7 Data
Collection……………..…………………………………………….… 19
3.8
Data Analysis……..……….…………………………………………………20
3.8.1 Genetic
Analysis……………………………………………………………20
3.9 Genetic
Phenotypic and Environmental correlation…..……………. 21
3.9.1 Genetic
Correlation (rG)……………………………………………………. 21
3.9.2 Phenotypic Correlation (rP)……………………………………………….
21
3.9.3 Environmental
Correlation (rE)……………………………………………. 22
CHAPTER
FOUR: RESULTS AND DISCUSSION
4.1 Monthly
Body Growth Performance.……..………………….…………… 25
4.2
Effect of Season of Birth and Sex of Animal…………………………….27
4.3 Variance
Components for performance Traits………………………………30
4.4 Heritability
Estimates ……………………………………………………… 31
4.4.1 Heritability Estimates for Reproductive
Traits ……….……………… 31
4.5 Phenotypic, Genotypic and Environmental Correlation
………… 32
4.6 Comparison
between Sires for Performance Traits …………………..34
CHAPTER
FIVE: SUMMARY, CONCLUSION AND RECOMMENDATION
Summary, Conclusion and Recommendations
……………………………36
REFERENCES ……………………………………………………………………38
APPENDIX………………………………………………………………………………………………51
Abstract
Twenty-five intensively managed mature West African Dwarf goats were
used for the experiment comprising 20 Does (dams) and 5 bucks (sires). The goats
were classified into 5 mating pens of 4 Does (dams) and one buck (sire)
randomly assigned per pen. Fresh water and forage were provided ad libitum in addition to 1kg
concentrates Cajanus cajan to each
animal per day. Data were collected on weights at birth and weaning; litter size
and linear body measurements. Body weight gain was calculated. The data were
subjected to analysis of variance in completely randomized design using the
statistical package of social science (SPSS) computer package. The Paternal Half-sib
Analysis model was used to estimate sire component of variance from which the
additive genetic variance and heritability were calculated. The descriptive
statistics (mean ±S.E) and Coefficient of Variation for birth weight, litter
size, body weight gain and body weight showed that birth weight of the
offspring were significantly different (P<0.05) between sires. The weaning
weight of offspring of different sire groups indicated non-significant differences
(P>0.05). Body weight gain of sires group recorded significant differences
(P<0.05). The effect of sex of the animal body weight, body weight gain,
body length, arm length and height at wither showed that male progenies were
higher than females; while the effect of season of birth indicated that kids
born in dry season had higher daily weight gain (44.16±3.11g) than those born
in wet season (42.32±3.74g). The heritability estimates for birth weight,
litter size and weaning weight were low, moderate and high (0.15, 0.22 and
0.88), respectively. The estimates of heritability for body length at birth
were moderate, while at 6 months of age the heritability was high (0.95) and
this indicates high potence for genetic improvement.
Linear body measurement traits (body length, arm length, and height at wither)
recorded high heritability values. Phenotypic, genotypic and environmental
correlations between pairs of parameters in West African Dwarf goat traits
ranged from -0.01 to 0.99.
CHAPTER 1
INTRODUCTION
The 2006 national census gave the population of
Nigeria as 144 million people (National Population Commission, 2006). With the
rate of population growth and rapid loss of indigenous livestock species
coupled with rising costs of production, the present gap in the supply of
animal protein is bound to widen. To bridge the animal protein demand and
supply gap, the Nigeria government since 1970s to date, has attempted to
improve indigenous breed of livestock by importing exotic breeds. These efforts
have failed principally because the exotic breeds could not adapt to the
tropical Nigerian environment as the challenges of tropical pests and diseases
were unbearable to them. Locally adapted breeds (indigenous breeds) are better
able to survive and produce valuable products in low input and variable
environments (AGRI, 2002).
Maijala
(1983) reported that genetic improvement is currently being conferred on
indigenous breeds of goats because they have long been adapted to extreme harsh
environmental conditions of nutrition, climate and disease. They might be more
productive in their own environment than exotic breeds. They can also be
valuable experimental animals in fundamental research and a potential store of
unique genes, which may be useful especially when environment concerns
necessitate changes in production system (Salako and Ngere, 2002). The
indigenous small ruminant populations in Nigeria comprising sheep and goats are
important genetic sources because of their adaptation characteristic such as
hardiness to the stressful tropical environment and trypano-tolerance (Salako,
2004). Of the several breeds of goats in the world, the predominant breed in
the humid tropics is the West African Dwarf goats. The majority of these are
bred under the traditional management and their contribution to the total
supply of meat in the region is enormous.
The
ability of farmers and buyers to relate the live animal measurements to growth
characteristics is essential for optimum production and value-based trading
system. This ability will also adequately reward livestock farmers rather than
the middlemen that tend to gain more profit in livestock production business
especially in developing countries (Afolayan et al., 2006). A study of linear body measurements on most farms in
the tropics is important because most farmers lack weighing scales and the
education to understand their manipulations (Gerald, 1994). Linear body
measurements can be used as a way of estimating weight and market value in
terms of cost of the animals (Gerald, 1994).
1.1 Objectives of the Study
GENETIC PARAMETERS OF GROWTH AND REPRODUCTION IN THE WEST AFRICAN DWARF GOATS REARED IN THE HUMID TROPICS
