Changes in the rate of genetic progress in the New Zealand sheep industry since 1990 are linked to structural aspects of breeding scheme design and to major industry sheep breeding initiatives. Data was sourced from the December 2007 SIL-ACE genetic evaluation for 140 recorded Dual Purpose flocks and 62 recorded Terminal Sire flocks. Genetic trends in both of these flock types approximately doubled after the introduction of Sheep Improvement Ltd. and there was a further incremental increase of similar magnitude after the introduction of the Central Progeny Test and SIL ACE. Substantial variation in the magnitude of genetic trends was observed across flocks within and between breeds. Large numbers of flocks average less than 50 cents gain in index per year, while significant numbers of flocks are achieving in excess of 150 cents gain per year. Flocks with higher rates of genetic gain tended to be using superior rams introduced from other flocks, while flocks with lower rates of genetic gain tended to be repeatedly using older sires of lower genetic merit. The implications of these results for industry sheep genetic improvement initiatives are discussed.
Proceedings of the New Zealand Society of Animal Production, Volume 69, Christchurch, 155-157, 2009
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