Genetic Parameter Estimates for Growth Curve Characteristics of Deccani Sheep

Abstract

Deccani sheep is an important breed of sheep found in semi-arid zones of India. The present study was based on the monthly body weights of 753 Deccani lambs maintained at ICAR-Network project during 2011 to 2015. The objectives of the study were to find the effect of various factors on the growth curve parameters estimated by Brody model and to estimate the genetic parameters of the growth curve. The Brody function was used to estimate the growth curve parameters for each lamb separately and then, growth parameter estimates were tested if there was significant influence of fixed effects of various factors. The genetic parameters of growth curve parameters were estimated under restricted maximum restricted likelihood procedure. The least-square estimates for mature weight (A), proportion of mature weight attained after birth (B) and maturation rate (k) were 30.68 ± 0.26, 1.82 ± 0.04 and 0.66 ± 0.01, respectively. Year of birth, season of birth and sex of lamb had significant influence on all growth curve parameters. The heritability estimates for A, B and k were low as 0.08 ± 0.06, 0.11 ± 0.07 and 0.07 ± 0.06, respectively. The phenotypic and genetic correlation between A and k was negative which indicated that early maturing leads to lower mature weights.