Estimation of genetic parameters for growth traits and Kleiber ratios in Boer x Central Highland goat

摘要

Accurate performance evaluation and genetic parameters estimation are the prerequisites for any successful genetic improvement program. This study was conducted to estimate genetic parameters for growth and Kleiber ratio traits in Boer x Central Highland goats. On-station data collected from 2009 to 2018 were utilized for the study. A general linear model procedure of the Statistical Analysis System (SAS, version 9.0) was used to analyze fixed effects, and genetic parameters were estimated using the WOMBAT software fitted animal model. The log-likelihood ratio test was used for selecting the best fitted model. Based on best fitted models, the total heritability (h(t)(2)) estimate for birth weight (BWT), weaning weight (WWT), six-month weight (SMWT), nine-month weight (NMWT), and yearling weight (YWT) were 0.38, 0.12, 0.05, 0.30, and 0.28, respectively. The total heritability (h(t)(2)) estimates for weight gain from birth to weaning (ADG1), 3 to 6 months (ADG2), 6 to 9 months (ADG3), and 9 to 12 months of age (ADG4) were 0.09, 0.08, 0.16, and 0.14, respectively. The heritability estimates for Kleiber ratios in different growth phases were found to be low (0.09 to 0.18) based on the selected models. Even with this figure, including the Kleiber ratio in the selection criteria would be imperative to improve the feed efficiency of crossbred goats. The direct genetic correlation estimates among growth traits range from 0.60 +/- 0.14 to 0.97 +/- 0.12. Except for NMWT, ADG4, and Kleiber ratio from 9 months to yearling age, the maternal effect had a significant influence on all considered traits. However, the contribution of the maternal genetic effect was more important for early growth traits. Thus, considering both the direct additive genetic effect and the maternal genetic effect is imperative for accurate genetic evaluation and for high selection response. The moderate heritability estimates for most of the growth traits implies the possibility of selection in conjunction with crossbreeding for a better genetic response. The positive and high genetic correlation estimates among growth traits confirm the possibility of a selection of goats at an early age.