IMPROVEMENT IN EGG PRODUCTION TRAITS IN THE LIGHT LOCAL CHICKEN ECOTYPE USING A SELECTION INDEX
ABSTRACT
Fifty hens and five cocks from a random mating population of light local chicken ecotype
(LLCE) were mated and the fertile eggs hatched to obtain the parent generation (G0) used for
this study aimed at improving egg production traits in the LLCE using a selection index. The
hens were monitored for short-term (90-days from first day of lay) egg production traits
namely: Body Weight at First Egg (BWFE), Average Egg Weight (AEW) and Total Egg
Number (TEN). Data obtained were subjected to statistical analysis using SPSS (2001) and
paternal half-sib model with Harvey (1990) to estimate descriptive statistics and genetic
parameters respectively. These were employed in constructing the selection index. Selection
for all the selection criteria (BWFE, AEW and TEN) was in the positive direction. Selected
parents were mated to produce next generations - G1 and G2. Selection differentials,
selection intensities and genetic response due to selection were also estimated. A control
population which spanned for three generations (each generation had its own control
population) was used to monitor environmental changes and to estimate the genetic changes
due to selection.
There were significant increases (P<0.05) in BWFE, AEW, and TEN in the
selected populations over the three generations of study such significant increases (P<0.05)
were not observed in the control population. Heritability estimates for all traits in all
generations and populations were moderate to high. The heritability of the index was also
moderate. Such moderate to high heritability estimates indicate high additive genetic
variances, implying that these traits were most passed on from the parents to their offspring.
Low to high positive genetic and phenotypic correlations was observed between BWFE and
AEW in all populations of study. The genetic correlation and phenotypic correlation between
BWFE and EN, and between AEW and EN, was moderate to highly negative for all
generations and populations of study. A positive genetic correlation was observed between
AEW and TEN in G2 of the selected population. A cumulative selection differential of
269.38g, 1.58g and 3.88 eggs were obtained for BWFE, AEW and TEN respectively.
Selection response for traits increased over the generations in a fairly linear manner.
Realized response per generation was estimated to be 94.22g, 0.84g and 4.85eggs for BWFE,
AEW and TEN respectively. It is evident that the simultaneous inclusion of BWFE, AEW,
and TEN in a selection index generally improved the performance of selected birds over the
generations in the Light Local Chicken Ecotype.
