Abstract

Lamb survival to weaning is an important determinant of farmer income and an animal welfare issue. The aim of this study was to determine whether skin thickness, fat depth and eye muscle depth (EMD) of the sires were related to skin thickness, fat depth, EMD and survival estimated breeding value (eBV) of their progeny. Data from a total of 19,436 lambs born between 2010 and 2013 inclusive were obtained from four farmers who comprise the Terminal Romneys for Increased Genetic Gain (TRIGG) group. Records included weaning weight, flock, sex, birth rank, date of birth, dam identity, sire identity and live weight at ultrasound measurement; skin thickness, fat depth and EMD measured using ultrasound at eight-months of age; and the survival eBV. Heritabilities for weaning weight, skin thickness, fat depth and EMD were 0.60±0.08, 0.21±0.07, 0.25±0.08 and 0.61±0.23 respectively. Skin thickness and EMD of the sire were positively correlated with progeny survival eBV while sire fat depth was negatively correlated with lamb survival eBV. Skin thickness, EMD and fat depth showed promise as indirect selection criteria for improved lamb survival. Additional data are required to confirm this.

IM, Tait, RE Hickson, PR Kenyon, and HT Blair

Proceedings of the New Zealand Society of Animal Production, Volume 75, Dunedin, 243-246, 2015