Comparison of three methods for estimating breeding values of Mecheri rams for body weights

Abstract

Estimates of breeding values were obtained for weights at birth, 3, 6, 9 and 12 months of age in Mecheri sheep maintained at Mecheri Sheep Research Station, Pottaneri, Tamil Nadu, India, over a period of 16 years (1991 to 2006). Records of 1763 lambs born out of 74 sires were used for the study. Analyses were carried out by least-squares (LS), best linear unbiased prediction (BLUP) and derivative free restricted maximum likelihood (DFREML) methods. Error variance for LS, BLUP and DFREML estimates were 0.153, 0.155 and 0.053; 3.573, 3.589 and 2.082; 6.529, 6.576 and 3.888; 8.697, 8.734 and 4.337 and, 8.324, 8.391 and 4.435 respectively for birth, 3, 6, 9 and 12 months weights. The coefficient of determination (R2) for LS, BLUP and DFREML methods were 24.7, 19.6 and 71.2; 32.6, 28.7 and 48.1; 37.0, 32.6 and 48.1; 39.0, 34.2 and 58.7 and, 46.9, 40.2 and 57.6 for birth, 3, 6, 9 and 12 months weights respectively. Spearman’s rank correlation for DFREML with BLUP and LS estimates were highly significant (P