Genetic and Non-Genetic Parameter Estimates for Growth Traits in Turkish Merino Lambs

Abstract

Genetic and non-genetic influences on the body weights of 8429 Turkish Merino lambs sired by 292 rams over 1992-2006 were evaluated. Traits analyzed were Birth Weight (BW), 3 Months Weight (3 MW), 6 Months Weight (6 MW), 12 Months Weight (12 MW), Pre-weaning Daily Gain (PRDG) and Post-weaning Daily Gain (PSDG). REML estimates of variance and covariance components were obtained by using animal models in which the fixed effects of year of lambing, sex, birth type and age of dam and random animal direct and the maternal genetic effects were included. Average weights were 4.31 +/- 0.02, 32.4 +/- 0.36 45.1 +/- 0.43, 53.4 +/- 0.55 kg; 315 +/- 4 and 76 +/- 2 g for BW, 3 MW, 6 MW, 12 MW, PRDG and PSDG, respectively. All environmental factors were statistically significant, except age of dam for PSDG. Estimates of direct and maternal heritabilities were 0.14, 0.16; 0.29, 0.03; 0.31, 0.05; 0.38,0.09; 0.29, 0.03 and 0.49, 0.10 for BW, 3 MW, 6 MW, 12 MW, PRDG and PSDG, respectively. Genetic and phenotypic correlations among traits were statistically significant and favorable. In general, heritability estimates are moderate and hence, genetic progress can be achieved through mass selection.