Trans-Tasman genetic evaluations of sheep: spreading the net wider

Abstract

At the instigation of local breed groups, Sheep Improvement Ltd. (SIL) and Sheep Genetics (SG) exchanged flock data and conducted genetic evaluations on the combined dataset. Results from each system show only modest changes in breeding values compared to analyses of their respective within country datasets. Correlations of breeding values (BVs) were 96 to 100% for weaning weight, autumn live weight, ultrasonic muscle, ultrasonic fat, fleece weight and number of lambs born. Correlations between BVs generated by the two systems from the same datasets were less strong but still good at 69 to 89%, for most traits. This was attributed to differences in parameters used by the two analysis systems and to some measurements being taken at different ages. The weakest correlations occurred for ultrasound scan traits at 14 to 65% since SG adjusts these to constant 'carcass' weight but SIL does not. It is concluded that the best option for breeders seeking superior genetics internationally is to facilitate data exchange and have analysis and reporting done within their own country.