粮食生产的巨大改善,由于有效的遗传选择和耕作方法的进步,是现代农业最伟大的成就之一。例如,在过去的五十年里,奶牛业的牛奶产量增加了一倍多,而奶牛的总数却大幅减少。这主要是通过生产系统的集约化来实现的,产奶量和有限数量的相关性状的直接遗传选择,以及现代技术的使用(例如,人工授精和基因组选择)。尽管生产效率大大提高,一路上出现了强烈的弊端。首先,跨品种的遗传多样性急剧下降,由于世界上很少使用常见的乳制品品种,以及品种内遗传多样性的大幅减少。对产奶量的密集选择也导致了与生育力相关的性状的不利遗传反应,健康,长寿,和环境敏感性。往前走,乳制品行业需要继续完善当前的选择指标和育种目标,以更加重视与动物福利相关的性状,健康,长寿,环境效率(例如,甲烷排放和进料效率),和整体韧性。Thisneedtobedonethroughthedefinitionofcriteria(features)that(a)representwellthebiologicalmechanismsunderlyingtherespectively表型,(b)是可遗传的,(c)可以在大量动物中尽可能早地进行经济有效的测量。奶牛产业的长期可持续发展还需要多样化的生产系统,对遗传资源的开发进行更大的投资,这些遗传资源对特定耕作系统中发生的扰动具有抵抗力,而对环境的控制较小(例如,有机,农业生态,以牧场为基础,山地放牧耕作系统)。保护,基因改良,应将当地品种的使用纳入现代奶牛业,并应更加注意避免奶牛种群进一步丧失遗传多样性。在这次审查中,我们承认在高产奶牛中取得的遗传进展,与奶牛场集约化密切相关,达到了极限。我们讨论了需要解决的关键点,以发展强大而长期的可持续乳制品行业,最大限度地提高动物福利(个体动物的基本需求和积极福利)和生产效率,同时也减少了环境足迹,所需的输入,对外部因素的敏感性。
The massive improvement in food production, as a result of effective genetic selection combined with advancements in farming practices, has been one of the greatest achievements of modern agriculture. For instance, the dairy cattle industry has more than doubled milk production over the past five decades, while the total number of cows has been reduced dramatically. This was achieved mainly through the intensification of production systems, direct genetic selection for milk yield and a limited number of related traits, and the use of modern technologies (e.g., artificial insemination and genomic selection). Despite the great betterment in production efficiency, strong drawbacks have occurred along the way. First, across-breed genetic diversity reduced dramatically, with the worldwide use of few common dairy breeds, as well as a substantial reduction in within-breed genetic diversity. Intensive selection for milk yield has also resulted in unfavorable genetic responses for traits related to fertility, health, longevity, and environmental sensitivity. Moving forward, the dairy industry needs to continue refining the current selection indexes and breeding goals to put greater emphasis on traits related to animal welfare, health, longevity, environmental efficiency (e.g., methane emission and feed efficiency), and overall resilience. This needs to be done through the definition of criteria (traits) that (a) represent well the biological mechanisms underlying the respective phenotypes, (b) are heritable, and (c) can be cost-effectively measured in a large number of animals and as early in life as possible. The long-term sustainability of the dairy cattle industry will also require diversification of production systems, with greater investments in the development of genetic resources that are resilient to perturbations occurring in specific farming systems with lesser control over the environment (e.g., organic, agroecological, and pasture-based, mountain-grazing farming systems). The conservation, genetic improvement, and use of local breeds should be integrated into the modern dairy cattle industry and greater care should be taken to avoid further genetic diversity losses in dairy cattle populations. In this
review, we acknowledge the genetic progress achieved in high-yielding dairy cattle, closely related to dairy farm intensification, that reaches its limits. We discuss key points that need to be addressed toward the development of a robust and long-term sustainable dairy industry that maximize animal welfare (fundamental needs of individual animals and positive welfare) and productive efficiency, while also minimizing the environmental footprint, inputs required, and sensitivity to external factors.