Abstract :
Genetic and phenotypic parameters were estimated from 1358 kids of Saudi Aradi goats
(A) and their crosses with Syrian Damascus (D) in two experimental stations in Saudi Arabia
between 2005 and 2010. Such crossbreeding plan resulted in four genetic groups of
AA, DD, ½D½A and ¾D¼A. The analysis of data was carried out by using a mixed animal
model to find out every combination of pairs of traits. The five fixed effects included in the
mixed model were location of the experiment, genetic group, year-season of birth, type
of birth, and sex; the random effects for each two traits were the additive genetic effects
for each of the two traits and the random error (temporary environmental effect). Crossbred
kids of ½D½A and ¾D¼A were heavier for all body weights relative to Saudi Aradi
kids. The lower values observed in all weights for ¾D¼A kids compared to those in ½D½A
are expected, which would confirm the fact that the estimates of direct heterosis were
positive for the majority of weights studied. Medium to high heritability estimates were
obtained for weights, ranging from 0.12 at the 8th week to 0.41 at birth. The increase in
estimates is commensurate with age: from the weight in the 8th week to the weight in
the 24th week. Genetic correlation estimates were generally medium to high, ranging from
0.40 to 0.99. Genetic correlations between adjacent body weights were higher than those
between non-adjacent estimates. Phenotypic correlations were positive, and generally of
lower significance than the genetic correlations.
