The cost-benefit of genomic testing of heifers and using sexed semen in pasture-based dairy herds.
The cost-benefit of genomic testing of heifers and using sexed semen in pasture-based dairy herds.
复制标题
小母牛基因组测试和在牧场奶牛群中使用性控精液的成本效益。
DOI：
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发表时间：
2018
影响因子：
3.5
通讯作者：
J. E. Pryce
中科院分区：
文献类型：
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作者：
Joanna E. Newton;Ben J. Hayes;J. E. Pryce
奶牛繁殖力和雌性生殖技术的最新进展为向雌性施加更大的选择压力提供了机会。这意味着可能有更大的动力去获取雌性的基因组育种值。我们模拟了关键参数的变化对使用和不使用性控精液的小母牛基因组测试的净收益的影响。本文建立在早期成本效益研究的基础上，但使用了与牧场系统相关的参数。使用确定性模型来评估由于以下方面的变化对净效益的影响：(1) 繁殖率、(2) 基因组测试成本、(3) 亲本育种值 (EBVPA) 的可用性和 (4) 替代率。当包括性控精液的使用时，我们还考虑了（1）与性控精液交配的小母牛和奶牛的比例，（2）使用性控精液授精的受孕率下降，以及（3）剩余小母牛的边际回报。替代率较低且无法获得 EBVPA 的场景具有最大的净收益。根据澳大利亚目前的参数，对于具有中等繁殖性能的牛群而言，基因分型小母牛一生中实现的基因组测试的净收益预计为每 100 头牛 204 澳元至 1,124 澳元。基因组测试的成本对许多农民来说是一个障碍，但对净收益的影响很小。如果考虑的唯一好处是增加小母牛替代品的遗传增益，那么单独进行基因组测试总是比同时使用性控精液和基因组测试更有利可图。当考虑其他收益（即，剩余小母牛与雄性小牛相比的更高销售价格）时，存在一些参数组合，其中使用性控精液和基因组测试的净收益高于仅基因组测试的同等情况。在以下情况下，使用性控精液和基因组测试最有可能有利可图：(1) 用于小母牛，(2) 出售剩余小母牛的边际回报（销售价格减去饲养成本）大于 400 澳元，以及 (3) 受孕率比使用传统精液实现的受孕率低不超过 10 个百分点。净收益高度依赖于边际回报。证明基因组测试的初始投资可以在测试的小母牛的一生中收回，这可能有助于扩展信息的开发，以解释在牛群水平上对雌性进行基因组测试的价值。
Recent improvements in dairy cow fertility and female reproductive technologies offer an opportunity to apply greater selection pressure to females. This means there may be greater incentive to obtain genomic breeding values for females. We modeled the impact of changes to key parameters on the net benefit from genomic testing of heifer calves with and without usage of sexed semen. This paper builds on earlier cost-benefit studies but uses parameters relevant to pasture-based systems. A deterministic model was used to evaluate the effect on net benefit due to changes in (1) reproduction rate, (2) genomic test costs, (3) availability of parent-derived breeding values (EBVPA), and (4) replacement rate. When the use of sexed semen was included, we also considered (1) the proportion of heifers and cows mated to sexed semen, (2) decreases in conception rate in inseminations with sexed semen, and (3) the marginal return for surplus heifers. Scenarios with lower replacement rates and no availability of EBVPA had the largest net benefits. Under current Australian parameters, the net benefit of genomic testing realized over the lifetime of genotyped heifers is expected to range from A$204 to A$1,124 per 100 cows for a herd with median reproductive performance. The cost of a genomic test, a perceived barrier to many farmers, had only a small effect on net benefit. Genomic testing alone was always more profitable than using sexed semen and genomic testing together if the only benefit considered was increased genetic gain in heifer replacements. When other benefits (i.e., the higher sale price of a surplus heifer compared with a male calf) were considered, there were combinations of parameters where net benefit from using sexed semen and genomic testing was higher than the equivalent scenario with genomic testing only. Using sexed semen alongside genomic testing is most likely to be profitable when (1) used in heifers, (2) the marginal return for selling surplus heifers (sale price minus rearing costs) is greater than A$400, and (3) conception rates of no more than 10 percentage points lower than those achieved using conventional semen can be realized. Net benefit was highly dependent on the marginal return. Demonstrating that the initial investment in genomic testing can be recouped within the lifetime of the heifers tested may assist in the development of extension messages to explain the value of genomic testing females at the herd level.