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.