Bovine tuberculosis (bTB) persists in many countries having a significant impact on public health and livestock industry finances. The incidence and prevalence of new cases in parts of the UK and elsewhere over the past decades warrant intensified efforts towards achieving Officially Tuberculosis Free (OTF) status in the respective regions. Genetic selection aiming to identify and remove inherently susceptible animals from breeding has been proposed as an additional measure in ongoing programmes towards controlling the disease. The presence of genetic variation among individual animals in their capacity to respond to Mycobacterium bovis exposure has been documented and heritability estimates of 0.06-0.18 have been reported. Despite their moderate magnitude, these estimates suggest that host resistance to bTB is amenable to improvement with selective breeding. Although relatively slow, genetic progress can be constant, cumulative and permanent, thereby complementing ongoing disease control measures. Importantly, mostly no antagonistic genetic correlations have been found between bTB resistance and other animal traits suggesting that carefully incorporating the former in breeding decisions should not adversely affect bovine productivity. Simulation studies have demonstrated the potential impact of genetic selection on reducing the probability of a breakdown to occur or the duration and severity of a breakdown that has already been declared. Furthermore, research on the bovine genome has identified multiple genomic markers and genes associated with bTB resistance. Nevertheless, the combined outcomes of these studies suggest that host resistance to bTB is a complex, polygenic trait, with no single gene alone explaining the inherent differences between resistant and susceptible animals. Such results support the development of accurate genomic breeding values that duly capture the collective effect of multiple genes to underpin selective breeding programmes. In addition to improving host resistance to bTB, scientists and practitioners have considered the possibility of reducing host infectivity. Ongoing studies have suggested the presence of genetic variation for infectivity and confirmed that bTB eradication would be accelerated if selective breeding considered both host resistance and infectivity traits. In conclusion, research activity on bTB genetics has generated knowledge and insights to support selective breeding as an additional measure towards controlling and eradicating the disease.

中文翻译：

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选择性育种有助于控制和根除牛结核病

牛结核病 (bTB) 在许多国家持续存在，对公共卫生和畜牧业财务产生重大影响。过去几十年来，英国部分地区和其他地方新病例的发病率和流行率需要加大力度，争取在各自地区实现正式无结核病 (OTF) 状态。旨在识别和消除繁殖中固有易感动物的基因选择已被提议作为正在进行的控制疾病计划的额外措施。个体动物对牛分枝杆菌暴露的反应能力存在遗传变异已被记录，遗传力估计为 0.06-0.18。尽管程度中等，但这些估计表明宿主对 bTB 的抗性可以通过选择性育种来改善。虽然相对缓慢，但遗传进展可以是持续的、累积的和永久性的，从而补充了正在进行的疾病控制措施。重要的是，bTB 抗性和其他动物性状之间大多没有发现拮抗的遗传相关性，这表明在育种决策中仔细考虑前者不会对牛的生产力产生不利影响。模拟研究证明了遗传选择对降低发生故障的可能性或已宣布的故障的持续时间和严重程度的潜在影响。此外，对牛基因组的研究已经确定了与 bTB 耐药性相关的多个基因组标记和基因。然而，这些研究的综合结果表明，宿主对 bTB 的抗性是一种复杂的多基因性状，没有任何一个基因可以单独解释抗性动物和易感动物之间的内在差异。这些结果支持开发准确的基因组育种值，适当捕捉多个基因的集体效应，以支持选择性育种计划。除了提高宿主对 bTB 的抵抗力外，科学家和从业者还考虑了降低宿主传染性的可能性。正在进行的研究表明，存在传染性遗传变异，并证实如果选择性育种同时考虑宿主抗性和传染性特征，将会加速 bTB 的根除。总之，bTB 遗传学研究活动产生了支持选择性育种的知识和见解，作为控制和根除该疾病的额外措施。