Abstract

Multi-generation data from 1985 to 2002 were analysed from a 200-ewe Perendale flock to investigate genetic and environmental relationships between ewe pre-mating liveweight change and live weight of their progeny at birth, weaning, and 1, 2, 3, 4 and 5 years of age. The flock was managed at Whatawhata Research Centre and then at Winchmore Research Station, with selection for either increased or decreased wool bulk at one year of age. A total of 162 rams were used in a single-sire system. Numbers of resulting dam-offspring pairs ranged from 3,510 for progeny birth weights, to 369 for daughter 5-year-old live weights. Genetic and environmental correlations of progeny trait on dam trait, and the derived genetic (bG) and environmental (bE) regressions, were obtained from a restricted maximum likelihood animal model with a relationship matrix, after adjustment for known fixed effects. The bG estimates were all non-significant, with 14 of the 20 estimates tending to be negative. Three of the 20 estimates of bE were significant, with values ranging from 0.7 to 1.3% of mean progeny weight per kg dam gain. The estimated environmental relationships were of insufficient magnitude to impact on the flock’s productivity in the short term.

RMW, Sumner, CA Morris, SM Hickey, and AM Sheppard

Proceedings of the New Zealand Society of Animal Production, Volume 70, Palmerston North, 165-170, 2010