ABSTRACT
This study “Genetic analysis of the first eight weeks body measurements of Hubbard broiler
breeder chickens in Shika Nigeria” was undertaken to estimate the genetic parameters of body
weights and linear measurements at different ages and to ascertain the extent to which linear
body measurements could best predict weight at 8 weeks. Data from 160 Hubbard broiler
breeders at the National Animal Production Research Institute (NAPRI) Shika, Zaria was used
for the study. Bi-weekly linear body measurements in centimeters were taken using a measuring
tape, while body weights measured in grams were taken weekly for 8 weeks using a digital scale.
Body conformation traits measured included; back length, chest circumference, chicken height
and shank length. The heritability (h2) estimates for body weight and conformation traits from 2
to 8 weeks were low to moderate. Genetic correlations for body weight ranged from low to high
but were positive in most cases except for correlations between 1 and, 5, 6, 7 and 8 weeks body
weights. Phenotypic correlations for body weights also ranged from low to high and were
positive in all cases (0.007-0.963). Genetic and phenotypic correlations for body weight and
conformation traits at 2 weeks were positive in most cases and ranged from low to high while the
genetic correlations for body weight and conformation traits at 4 weeks were high and positive in
most cases except for correlations between body weight and chicken height which was low and
negative, while phenotypic correlations ranged from moderate to high (0.330-0.744). At 6 weeks,
the genetic and phenotypic correlations for body weight and conformation traits were all high
and positive, while genetic correlations at 8 weeks were positive and ranged from moderate to
high, whereas the phenotypic correlations were all high and positive. From this study, chest
circumference at 6 weeks could be used for selection as parents of the next generation, while
back length at 8 weeks was the best predictor of 8 week body weight.
TABLE OF CONTENTS
Cover page————————————————————————————
Title page ————————————————————————————
Declaration ———————————————————————————-
Certification ———————————————————————————
Dedication————————————————————————————–
Acknowledgement ————————————————————————–
Abstract—————————————————————————————–
Table of content——————————————————————————
List of tables———————————————————————————-
List of figures——————————————————————————–
List of appendices —————————————————————————
CHAPTER ONE
INTRODUCTION ———————————————————————-
CHAPTER TWO
LITERATURE REVIEW ————————————————————–
Broiler breeder —————————————————————————–
Hubbard male line ————————————————————————–
Hubbard white male ————————————————————————
Hubbard yellow male ———————————————————————–
Fertility—————————————————————————————-
CHAPTER THREE
MATERIALS AND METHODS ——————————————————–
Study location ———————————————————————————
Base population ——————————————————————————
Hatching activities —————————————————————————
Collection of fertile eggs ———————————————————————
Egg Setting ————————————————————————————-
Egg candling ———————————————————————————–
Hatching operations ————————————————————————–
Brooding/Rearing—————————————————————————–
Data collection ——————————————————————————–
Linear body measurements ——————————————————————
Data analysis ———————————————————————————–
Genetic parameter estimates —————————————————————–
Heritability ————————————————————————————-
Estimation of correlations ——————————————————————–
CHAPTER FOUR
RESULTS————————————————————————————
Body measurement characterization of hubbard broiler breeder chickens by age
Effect of fixed factors on body weight and conformation traits———————–
Effect of sire on body weight and conformation at different ages ——————-
Effect of hatch and sex on body weight and conformation traits at different ages-
Heritability estimates ———————————————————————–
Heritability and least square means with standard errors of egg weight, day old
weight and chick yield ———————————————————————
Heritability estimate of body weight and conformation traits by age—————-
Genetic and phenotypic correlations among weight the measurements ————–
Environmental correlations of various weight measurements of Hubbard broiler
breeders —————————————————————————————
Genetic and phenotypic correlations of body weight and conformation traits at
various ages———————————————————————————–
Genetic and phenotypic correlations of body weight and conformation traits at 2
weeks ——————————————————————————————–
Genetic and phenotypic correlations of body weight and conformation traits at 4
weeks ——————————————————————————————
Genetic and phenotypic correlations of body weight and conformation traits at 6
weeks ——————————————————————————————–
Genetic and phenotypic correlations of bodyweight and conformation traits at 8
weeks ——————————————————————————————–
Environmental correlations amongst body weight and conformation traits at various
ages————————————————————————————-
Environmental correlations amongst body weight and conformation traits at 2
weeks ——————————————————————————————–
Environmental correlations amongst body weight and conformation traits at 4
weeks ——————————————————————————————–
Environmental correlations amongst body weight and conformation traits at 6
weeks ——————————————————————————————–
Environmental correlations amongst body weight and conformation traits at 8
weeks———————————————————————————————
Prediction equations for 8 weeks body weight of hubbard broiler breeders
by age using body linear measurements————————————————–
CHAPTER FIVE
DISCUSSION
Body measurement characterization of hubbard broiler breeder chickens by age—–
Sire effect on body weight and conformation traits at different ages ——————-
Effect of hatch and sex on body weight and conformation traits at different ages —
Heritability estimates for body weight measurements, egg weight, day old weight
and chick yield ———————————————————————————
Genetic and phenotypic correlations —————————————————–
Environmental correlations between egg weight, chick yield and body weights
of Hubbard broiler breeder —————————————————————
Genetic and phenotypic correlations of body conformation traits at different ages
Environmental correlations for conformation traits at different ages ————–
Prediction equations for 8 weeks body weight of hubbard broiler breeders by age
using body linear measurements———————————————————-
CHAPTER SIX
SUMMARY CONCLUSION AND RECOMMENDATIONS
Summary————————————————————————————
Conclusion———————————————————————————-
Recommendation—————————————————————————
REFERENCES—————————————————————————–
APPENDICES——————————————————————————
CHAPTER ONE
1.0 INTRODUCTION
Broiler chicken is a young tender chicken suitable for roasting or broiling. Broiler breeders on the other
hand are birds reared to reproduce commercial broilers. They grow more efficiently due to positive
results from broiler genetic selection strategies. (Ewart, 1993).
The primary goal of broiler breeding is to improve profitability of broiler meat production. Until recently
most birds were sold whole, but there has been a dramatic increase in the proportion of birds being
grown for portioning and further processing (Ewart, 1993). Poultry production and processing
technologies have become rapidly accessible and are being implemented on a worldwide basis, which
will allow continued expansion and competitiveness in the meat sector (Aho, 2001). Therefore, the
success of poultry meat production has been strongly related to improvements in growth and carcass
yield, mainly by increasing breast proportion and reducing abdominal fat. Intensive selection of meattype
chickens for growth for more than 50 years has increased growth rate but rapid growth has been
accompanied by a number of negative consequences, including an increase in fat deposition.
(Zerehdaran et al., 2004)
The Nigerian poultry industry has over the years witnessed the introduction of different broiler strains
(Essien and Adeyemi, 1999). The realization of the full growth potentials of these strains is largely
expected to depend on the nutritional and climatic variables, subject however to the genotypic traits
which in turn set a ceiling on their productive capacity. The implication is that the broiler producer
should select stocks which have the genetic potential for fast growth rate and attainment of market
weight early enough under the Nigerian climatic conditions. Within the last one decade, there has been
an intensified study on the genetic, physiological, nutritional and growth performance of such imported
hybrids as Cobb, White Ross, Lohmann Brown, Hypercom Hubbard, Anak, Shaers, and Perdue among
others, (Essien and Adeyemi, 1999).
Body weight at market age is considered to be the single most important trait in determining profit from
a broiler enterprise (Mishra et al., 1995). Literature reports suggest that body weight is highly heritable
and responds well to mass/individual selection (Saxena and Mohapatra, 1981; Mishra, 1986).
Continuous selection has helped to reduce the age at marketing during the last four decades. As a result,
body weight of 1.5kg in broilers which was possible at 12 weeks of age is now achieved at 5-6 weeks
(Mishra et al., 1995).
Apart from body weight, a number of conformation traits are known to be good indicators of body
growth and market value in broilers (Ibe, 1989). Such conformation traits include shank length, breast
width, keel length, wing span, chicken height, body length, thigh length and head circumference.
The relationships between body weights and conformation traits have been found to have important
implications in the production of broilers with desirable body conformation (Ibe and Nwakalor, 1987). In
addition Okon et al. (1996) reported that the relationships between body weight and conformation
traits are direct and positive. As such the knowledge of this relationship would help breeders organize
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their programme in order to achieve optimum combination of body weight and good conformation for
maximum economic returns (Adeniji and Ayorinde, 1990).
Monsi (1992) noted that interrelationships among body measurements can be applied speedily in
selection and breeding. Chambers and Fortin (1984) added that the importance of evaluating
interrelationships and productivity traits in poultry lies in their usefulness as predictors of characteristics
like body weight. Such applications could speed up the assessment of traits through the involvement of
simple measurement tools like ruler or tape. Such simple linear measurements that can predict body
weight without necessitating bird slaughter will be particularly desirable. However, the knowledge of
genetic parameters such as heritability, genetic and phenotypic correlations will be required for further
genetic improvement in a broiler breeder enterprise. This study was therefore designed to:
1) Estimate genetic parameters for body weights and body linear measurements at different
ages.
2) Ascertain the extent to which linear body measurements could be used to predict body
weights.
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