Records of weights for 442 Romanov lambs were used to estimate genetic parameters and breeding values for growth traits of lambs .Traits studied were birth weight (BW), weaning weight (WW) and average daily gain from birth to weaning (ADG). Lambs weaned at approximately three months of age. Variance components were estimated by using Multivariate Derivative Free Restricted Maximum Likelihood (MTDFREML) program .The model Included year, sex, and type of birth as a fixed effect, and random effects for the direct genetic effect of the animal. Genetic and environmental correlations were estimated. Estimates of the variances of random effects (h2) as a proportion of phenotypic variance were 0.17, 0.20 and 0.19 for BW, WW and ADG, respectively. Estimate of genetic correlation was 0.24 between BW and WW, 0.63 between BW and ADG and -0.10 between WW and ADG. Estimates of environmental correlation was -0.35 between BW and WW,-0.16 between BW and ADG and 0.32 between WW and ADG.
Results suggest that, selection should be effective for WW and ADG, but less effective for BW. The estimate of genetic correlation showed a large genetic antagonism between BW and ADG. The wider range of animals and sires breeding values, indicating potential for genetic improvement for different traits studied in the present study.