Genetic progress evaluation of growth traits in Moghani sheep

Abstract

For evaluation of growth traits' genetic progress, pedigree information of 39408 Moghani sheep, between 1986 to 2016, at the breeding station of Moghani sheep was used. Studied traits included birth weight, weaning weight, six months weight, nine months weight, and one yearling weight. Variance components and genetic parameters of traits were estimated by restricted likelihood and six animal models using Wombat software. Direct heritability of birth weight, weaning weight, six months weight, nine months weight, and one yearling weight was (0.07, 0.09, 0.15, 0.13, and 0.20 respectively). Breeding values for the calculation of genetic trends for each trait were estimated by using the univariate best animal model. Phenotypic, genetic, and environmental trends of traits were estimated via regression of phenotypic average, breeding value average, and difference of breeding value from phenotypic value divided by birth year. The calculated genetic trends of birth weight, weaning weight, six months weight, nine months weight, and yearling weight were 0.008, 0.012, 0.054, 0.74, and 0.145 kg/year respectively, except for birth weight, the others were significant (p<0.01). The genetic gain of traits including birth weight, weaning weight, six months weight, nine months weight, and one yearling weight was estimated (0.213, 1.071, 1.171, 1.164, and 1.324 kg respectively). At evaluated years, many fluctuations were observed in the genetic trend of traits. In other words, it seems at the studied years, there wasn't a comprehensive plan for genetic breeding and improvement of body weight traits in Moghani sheep.