随着我们更好地了解健康与生产潜力和动物福利的关系,对奶牛健康的兴趣持续增长。在过去的十年里,已努力将健康特征纳入国家遗传评估。然而,他们专注于成熟的牛,小腿健康在很大程度上被忽视了。腹泻和呼吸道疾病是与小腿健康有关的主要疾病。控制小牛疾病的常规方法包括将小牛从大坝和小牛单独分离。然而,公众对这些方法的关注,越来越多的证据表明这些方法可能会对小腿发育产生负面影响,这意味着乳制品行业可能会放弃这些做法。遗传选择可能是解决这些重大疾病问题的有希望的工具。在这次审查中,我们研究了通过遗传学增强小腿健康的现有文献,并讨论了通过使用流行病学建模方法改善小腿健康的替代方法。以及通过改善初乳质量间接选择改善小腿健康的潜力。腹泻观察量表的遗传力估计值为0.03至0.20,而呼吸道疾病,估计范围从0.02到0.24。这些范围的宽度是应该的,至少在某种程度上,疾病患病率的差异,人口结构,数据编辑和模型,以及数据收集实践,在比较文献价值时,都应该考虑到这一点。将流行病学理论纳入数量遗传学为更好地确定疾病性状的遗传变异水平提供了机会,因为它解释了同时代人之间的疾病传播。初乳的摄入是决定小牛是否发生呼吸道疾病或腹泻的主要因素。初乳性状具有连续测量和报告的优势,这消除了传统上与二元疾病特征相关的问题。总的来说,遗传选择改善小腿健康是可行的。然而,为了确保最大的响应,任何行业成员的第一步都应集中努力标准化记录实践,并鼓励通过群体管理软件将信息上传到基因评估中心,因为高质量的表型是任何成功育种计划的支柱。
Interest in dairy cow health continues to grow as we better understand health\'s relationship with production potential and animal welfare. Over the past decade, efforts have been made to incorporate health traits into national genetic evaluations. However, they have focused on the mature cow, with calf health largely being neglected.
Diarrhoea and respiratory disease comprise the main illnesses with regard to calf health. Conventional methods to control calf disease involve early separation of calves from the dam and housing calves individually. However, public concern regarding these methods, and growing evidence that these methods may negatively impact calf development, mean the dairy industry may move away from these practices. Genetic selection may be a promising tool to address these major disease issues. In this
review, we examined current literature for enhancing calf health through genetics and discussed alternative approaches to improve calf health via the use of epidemiological modelling approaches, and the potential of indirectly selecting for improved calf health through improving colostrum quality. Heritability estimates on the observed scale for
diarrhoea ranged from 0.03 to 0.20, while for respiratory disease, estimates ranged from 0.02 to 0.24. The breadth in these ranges is due, at least in part, to differences in disease prevalence, population structure, data editing and models, as well as data collection practices, which should be all considered when comparing literature values. Incorporation of epidemiological theory into quantitative genetics provides an opportunity to better determine the level of genetic variation in disease traits, as it accounts for disease transmission among contemporaries. Colostrum intake is a major determinant of whether a calf develops either respiratory disease or
diarrhoea. Colostrum traits have the advantage of being measured and reported on a continuous scale, which removes the issues classically associated with binary disease traits. Overall, genetic selection for improved calf health is feasible. However, to ensure the maximum response, first steps by any industry members should focus efforts on standardising recording practices and encouragement of uploading information to genetic evaluation centres through herd management software, as high-quality phenotypes are the backbone of any successful breeding programme.