Genetic and non-genetic parameter estimates for growth traits of Bharat Merino lambs

Genetic and non-genetic influences on the body weights of 2425 Bharat Merino lambs sired by 154 rams over 1982-1996 were evaluated. Year and season of lambing, sex of lamb, type of birth, age of dam and ewe weight were significant sources of variation for lamb weights and daily gains. The average lamb weights were 3.1 +/- 0.03 kg at birth, 15.0 +/- 0.2 kg at 3 months, 21.6 +/- 0.2 kg at 6 months, and 29.1 +/- 0.3 ka at 12 months of age, and average daily gains were 133 +/- 1.6 and 52 +/- 0.9 a at pre- and post-weaning periods, respectively. Correspondingly, estimates of heritability were 0.23 +/- 0.07, 0.14 +/- 0.06, 0.52 +/- 0.09, 0.51 +/- 0.09, 0.17 +/- 0.07 and 0.56 +/- 0.09. Genetic and phenotypic correlations among growth traits were significant and in the desirable direction. These estimates demonstrate that there is an opportunity for improvement of Bharat Merino lambs based on selection for growth rate. (C) 2001 Elsevier Science B.V. All rights reserved.