Abstract :
The objective of this study was to determine the genetic parameters and variance components
of the economically important fleece traits staple fineness (SF), staple length (SL),
fiber diameter (FD) and fiber length (FL) in yearling Inner Mongolia Cashmere goats (IMWC).
Data collected in 2008–2011 from 5 Arbas Cashmere goat flocks were analyzed. Fixed effects
were determined using a generalized linear model with least square means. Variance components
and genetic parameters were determined using the restricted maximum likelihood
method. By ignoring or including maternal additive genetic effects and maternal permanent
environment effects, and considering whether direct additive genetic and maternal
additive genetic effects were correlated or not, six different single-trait animal models were
obtained. A log likelihood ratio test was conducted to choose the most appropriate model.
Then, genetic correlations among fleece traits were obtained using the average information
restricted maximum likelihood method with multi-trait models. Year of production
and herd had highly significant influences on all fleece traits (P < 0.01). Sex had highly significant
influences on all fleece traits (P < 0.01) except SF. Dam ages had a significant effect
on FD (P < 0.05), but was not related to other three traits. Type of birth had no significant
effect on the fleece traits in this study (P > 0.05). The log likelihood ratio test indicated that
neither maternal additive genetic effects nor maternal permanent environment effects had
a significant influence on the traits examined in this study. Direct additive heritabilities
(h2d
) were 0.27, 0.28, 0.34 and 0.17 for SF, SL, FD and FL, respectively, which is moderate
to low. Direct additive genetic correlations were negative (−0.40) between SL and SF, but
were positive (0.45) between SF and FD. Genetic correlations among the other traits were
low, ranging from −0.17 to 0.12. The purpose of this study was to determine the genetics
parameters of fleece traits to help improve the genetics of the Inner Mongolia Cashmere
goats (IMWC).
