Factors affecting the sex ratio in dairy cattle in New Zealand
作者： Johnson Di , Burton Lj , Xu Zz
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摘要: The sexes of calves born in 1996 (n = 319,539) and 1997 408,381) to artificial insemination selected herds were analysed study the effects region, dam breed, age, semen type, sires on sex ratio calves. There was a significant (P < 0.001) effect type ratio; frozen resulted 1.66% 1.24% more male than fresh semen, respectively, seasons. also 0.01) variation among ratio, but heritability estimate for low (h 2 0.02). No other significant. Industry-wide use will result heifer from which future replacements can be selected.
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