Abstract

The accumulation of faecal material around the breech area of sheep (dags) is of interest to the New Zealand sheep industry for a variety of reasons, including financial penalties for presenting animals with dags at slaughter, reduced wool value, increased risk of flystrike and the labour cost associated with dagging both lambs and adult ewes (Pickering et al. 2012). Currently, dag scores at both three (DAG3) and eight (DAG8) months of age are routinely measured, and analysed in Sheep Improvement Limited (SIL). However, there are currently no formally published estimates of the genetic relationship between dag score as a lamb and dag score as an adult (DAGA) in the New Zealand sheep population. Adult dag score has been found to be highly repeatable between 12 months to two years of age (R = 0.42) and between two and three years of age (R = 0.44) in different strains of Merino sheep (Larsen et al. 1995). Currently within SIL, the estimated breeding values (EBVs) calculated from DAG8 measures are reported as the adult dag score EBVs. There are now, however, multiple flocks recording adult dag score in the SIL database. An analysis of the correlation of adult dag score with DAG8 and DAG3 would confirm if the current SIL model is appropriate for reporting adult dag EBVs, or if the model needs revising to include adult dag measures and its correlations with DAG3 and DAG8.

KM, Mcrae, KG Dodds, S-AN Newman, LF Brito, NK Pickering, and JC McEwan

Proceedings of the New Zealand Society of Animal Production, Volume 76, Adelaide, 144-145, 2016