South African Journal of Animal Science 2001, 31(3) © South African Society of Animal Science

Genetic and phenotypic correlations were estimated between lamb and ewe traits in a flock of Sabi sheep reared at the Matopos Research Station. Direct additive estimates of heritability were: 0.28 ± 0.04; 0.17 ± 0.00; 0.25 ± 0.01; 0.39 ± 0.01; 0.59 ± 0.01; 0.50 ± 0.01; 0.68 ± 0.03; 0.12 ± 0.003; 0.25 ± 0.01; 0.11 ± 0.00; 0.12 ± 0.00; for birth weight, weaning weight (120 days), 12 month weight, 18 month weight, ewe mating weight, post partum weight, ewe weight at weaning of lamb, total weight of lamb weaned, slaughter weight, hot and cold carcass weights respectively. Genetic correlations between birth weight and other weights to 18 months were high (0.75-0.85), whilst the relationship between weaning, 12 month and 18 month weight was close to unity. The genetic correlation between birth weight and ewe weights (mating, post-partum and dam weight at weaning of lamb) were moderate viz.0.51 ± 0.08, 0.40 ± 0.09, 0.49 ± 0.07 respectively and were close to unity at 18 months of age viz. 0.96 ± 0.02, 0.92 ± 0.03, and 0.84 ± 0.03 respectively. Total weight of lamb weaned was moderately correlated to birth weight (rg = 0.46 ± 0.15) but tended to be highly correlated with 18 month weight (0.92 ± 0.10) and ewe weights (0.75 ± 0.09-0.91 ± 0.07). The genetic correlation between birth weight and slaughter and carcass weight was moderate and was high at 18 months. The heritability estimates from a univariate logit transformed analysis for fertility