Bascom S S, Young A J
Department of Animal and Nutritional Sciences, University of New Hampshire, Durham 03824, USA.
J Dairy Sci. 1998 Aug;81(8):2299-305. doi: 10.3168/jds.S0022-0302(98)75810-2.
A study was conducted to determine why cows are culled, whether cows are culled for multiple reasons, and whether farm characteristics can help explain why cows are culled. The primary reasons for culling were reproduction (i.e., failure to conceive), mastitis, and low production. For 35% of all cows that were culled, a secondary reason for culling was assigned by the farmer, and, for 11% of all cows that were culled, a tertiary reason was recorded. Using a weighting factor of 5:3:1 (primary:secondary:tertiary reasons for culling), a culling score was computed for each reason within a herd. Reproduction was the primary reason for culling, production was second, and mastitis was third. Much variation existed as to why dairy farmers culled cows. Computed mean culling scores suggested that culling for mastitis was lower in high producing Holstein herds, and culling for abortion was higher in high producing Holstein herds. Culling for reproduction was higher in high producing Holstein herds, and culling for production was lower in high producing Holstein herds. Culling for mastitis and production were significantly lower in high producing Holstein herds than in non-Holstein herds. A system that allows the documentation of multiple reasons for culling and the computation of a composite score appears to be reasonable for the assessment of culling management.
开展了一项研究，以确定奶牛被淘汰的原因、奶牛是否因多种原因被淘汰，以及农场特征是否有助于解释奶牛被淘汰的原因。淘汰的主要原因是繁殖问题（即未能受孕）、乳腺炎和产量低。在所有被淘汰的奶牛中，35% 的奶牛，农民指定了第二个淘汰原因，11% 的奶牛记录了第三个淘汰原因。使用 5:3:1 的加权因子（淘汰的主要、次要、第三个原因），计算了牛群中每个原因的淘汰分数。繁殖是淘汰的主要原因，产量其次，乳腺炎第三。奶农淘汰奶牛的原因存在很大差异。计算出的平均淘汰分数表明，高产荷斯坦牛群中因乳腺炎而淘汰的比例较低，而高产荷斯坦牛群中因流产而淘汰的比例较高。高产荷斯坦牛群中因繁殖问题而淘汰的比例较高，因产量问题而淘汰的比例较低。高产荷斯坦牛群中因乳腺炎和产量问题而淘汰的比例明显低于非荷斯坦牛群。一个允许记录多种淘汰原因并计算综合分数的系统，对于评估淘汰管理似乎是合理的。
