Genetic parameters for weight, fat and eye muscle depth in South Australian Merino sheep

Abstract

Data from the SARDI Selection Demonstration Flocks were used to estimate heritability of and genetic correlations between live weight, fat depth and eye muscle depth at five months of age under an animal model. Two models, with and without weight adjustment, were used for fat and eye muscle depth. Heritability estimates were 0.28 (0.08), 0.26 (0.06) and 0.35 (0.07) for weight, adjusted fat and adjusted eye muscle depth, respectively. Phenotypic correlations ranged from 0.27 to 0.66 and genetic correlations ranged from 0.16 to 0.73. The estimates reported here are similar to those previously reported for other sheep breeds. This suggests that sufficient genetic variation exists to enable selection to improve these traits for Merinos. Moderate heritabilities and correlations for weight adjusted traits suggest that there is potential for improvement in fat depth and eye muscle shape in Merinos. The similarity of these estimates to those reported for other sheep breeds indicates that selection used for meat breeds may be directly applicable to, or easily adapted for Merinos.