Genetic trends estimation for some of the growth traits in arman sheep

Abstract

In this study, 6574 growth trait records of Annan sheep bred and reared in Abbas-Abaci sheep breeding station, Mashhad, Iran during 1997-2007 were used to estimate the genetic trends for some of the growth traits using Animal model for lambs, rams and ewes. Genetic trends were estimated for Birth Weight (BW), Weaning Weight (WW) and 6 Months Weight (6 MW) traits. Appropriate models from snigle and three-trait analysis were applied for research of traits. Predicted breeding values averaged by year of birth from both the single and three-trait analysis for growth traits increased over time. Genetic trends of studied traits were estimated by regressing mean of breeding values on birth year. Direct genetic trends were positive and highly significant (p