Genetic parameter estimates of average daily weight gain traits for autosomal and sex-linked chromosomes in Markhoz goats

This study was conducted for genetic analysis of Markhoz goats for autosomal and X chromosomes for average daily gain traits from birth to yearling. The data set contained 3837 average daily gain from birth to weaning (ADG1), 3467 average daily gain from weaning to 6-month (ADG2), 3133 average daily gain from 6-month to 9-month (ADG3) and 2726 average daily gain from 9-month to 12-month (ADG4) collected during 1992-2014 in Markhoz Goat Breeding Center of Sanandaj. Fixed effects affecting the studied traits were determined using Proc GLM of the SAS 8.2 software and variance components and genetic parameters were estimated by Average Information algorithm of Restricted Maximum Likelihood (AI-REML) using Wombat software. The most appropriate model for each trait was determined by Akaike’s Information Criterion (AIC) test. Direct autosomal heritability estimates for ADG1, ADG2, ADG3 and ADG4 were 0.14±0.03, 0.00±0.02, 0.14±0.04 and 0.06±0.03, respectively. X-linked direct heritability estimates for these traits were negligible values of 0.00±0.02, 0.08±0.02, 0.06±0.02 and 0.04±0.02, respectively. Maternal heritability for ADG1 and ADG3 were 0.06±0.02 and 0.04±0.03, respectively. Maternal permanent environmental variance for ADG3 and ADG4 were 0.03±0.02. The low estimations of direct heritabilities for autosomal and sexual chromosomes were obtained in the current study, therefore direct selection for these traits would be generate a relatively slow genetic progress.