Prediction of dairy bull fertility from field data: Use of multiple services and identification and utilization of factors affecting bull fertility
Prediction of dairy bull fertility from field data: Use of multiple services and identification and utilization of factors affecting bull fertility
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DOI：
10.3168/jds.2007-0743
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发表时间：
2008-06-01
影响因子：
3.5
通讯作者：
Hutchison, J. L.
中科院分区：
文献类型：
--
作者：
Kuhn, M. T.;Hutchison, J. L.
本研究的目的是评估多种服务的效用，而不是第一次服务，并扩大服务公畜长期预测公牛人工授精受胎率（CR）在美国。扩展服务公畜项的目的是确定是否可以通过估计模型中明确影响公牛CR的因素来提高准确性，然后将公牛的预测公式化为他自己的服务公畜解沿着与其他因素的解的总和。扩展服务公畜期限考虑的因素包括交配时公牛的年龄、种马、服务公畜的近亲繁殖、交配的近亲繁殖（潜在胚胎）和加性遗传效应。模拟和现场数据被用来研究的目标。在模拟中，预测与真实值进行比较，而与真实的数据，预测与公牛的平均CR在预留数据进行比较。使用哺乳期1至5的现场数据包括分布在43个州和12年（1995年至2006年）的1，419个牛群中的3，312，998头繁殖的737，626头荷斯坦奶牛。使用多个服务和扩展的服务父系术语提高了预测的准确性。多项服务的准确性提高了7%至9%，而扩展的服务父系术语的准确性提高了约12%。准确性的提高取决于可用服务的数量，但即使是至少有500次交配的公牛，多种服务和扩展服务的父系术语的组合可以预期导致准确性的总体提高至少20%。在预留数据中，预测和公牛平均CR之间的平均差异表明，这种准确性的提高可以在不引入偏见的情况下实现。人工授精公牛CR的遗传力估计值基本为零。因此，使用加性遗传效应的服务公畜将不会在预测公牛生育力的援助。扩展服务父系术语中使用的所有4个其他因素都有助于提高准确性，尽管到目前为止，交配时公牛的年龄是主要因素（包括时与未来年份CR的相关性为55.2%，不包括时为44.0%）。允许螺柱效应随年份而变化，并仅使用螺柱最近一年的预测解决方案被证明是优于单独使用螺柱的上级。
The objectives of this research were to assess the utility of multiple services, rather than first service only, and an expanded service sire term for prediction of bull conception rate (CR) by artificial insemination in the United States. The intent with the expanded service sire term was to determine whether accuracy could be improved by estimating factors affecting the bull's CR explicitly in the model and then formulating the bull's prediction as the sum of his own service sire solution along with the solutions for the other factors. Factors considered for the expanded service sire term included age of the bull at the time of mating, stud, inbreeding of the service sire, inbreeding of the mating (potential embryo), and an additive genetic effect. Both simulated and field data were used to study the objectives. In simulation, predictions were compared with true values, whereas with real data, predictions were compared with the bulls' average CR in set-aside data. Field data, using lactations 1 to 5, included 3,312,998 breedings of 737,626 Holstein cows in 1,419 herds distributed over 43 states and across 12 yr (1995 to 2006). The use of both multiple services and an expanded service sire term improved the accuracy of predictions. Multiple services contributed a 7 to 9% increase in accuracy, whereas the expanded service sire term improved accuracy by an estimated 12%. The amount of improvement in accuracy depends on the number of services available, but even for bulls with at least 500 matings, the combination of multiple services and an expanded service sire term can be expected to result in an overall increase in accuracy of at least 20%. Mean differences between predictions and bulls' average CR in set-aside data indicated that this improvement in accuracy can be brought about without introducing bias into the evaluations. Heritability estimates for artificial-insemination bull CR were essentially zero. Thus, use of an additive genetic effect for the service sire will not be of assistance in predicting bull fertility. All 4 of the other factors used in the expanded service sire term contributed to improved accuracy, although age of the bull at the time of mating was, by far, the major factor (correlation of 55.2% with future-year CR when included, 44.0% when not included). Allowing the stud effect to vary by year and using only the stud's most recent year solution in prediction were shown to be superior to using stud alone.