Modeling genetic covariance structure across ages of fleece traits in an Inner Mongolia cashmere goat population using repeatability and multivariate analysis.

Abstract: The objective of this study was to estimate the parameters necessary to determine whether the genetic expression of fleece traits in Inner Mongolia Arbas cashmere goats was unified at different ages. Fleece traits, including fiber diameter (FD) and fiber length (FL), were measured between 2008 and 2012, as goats aged from 1 to 5 years old, and were modeled using repeatability and several multivariate models that varied in covariance structure. Bayesian information criteria were used to choose the most ideal model. In the preferred model, FD could be partitioned into yearlings and older goats, while FL could be partitioned into yearlings, 2 year olds, and older goats. The heritabilities of FD in yearlings and older goats were 0.35 and 0.27, respectively, and the genetic correlation between yearlings and older goats was 0.93. For FL, the estimates of heritability were 0.18, 0.38, and 0.29 within the 3 age groups. The genetic correlations were 0.94 for yearlings with 2 year olds and older goats and close to 1.00 for 2 year olds with older goats. These findings provide useful information for designing more ideal and effective breeding programs to improve fiber quality. [Copyright &y& Elsevier]