Banos Georgios
Scotland's Rural College (SRUC), Department of Animal and Veterinary Sciences, Easter Bush, Midlothian, EH25 9RG, UK.
Ir Vet J. 2023 Aug 24;76(Suppl 1):19. doi: 10.1186/s13620-023-00250-z.
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.
牛结核病（bTB）在许多国家持续存在，对公众健康和畜牧业财政产生重大影响。在过去几十年里，英国部分地区及其他地方新病例的发病率和流行率，促使人们加大力度，以在各自地区实现官方无结核病（OTF）状态。在当前控制该疾病的计划中，已提议通过基因选择来识别并淘汰具有内在易感性的动物用于繁殖。已有文献记载，个体动物对牛分枝杆菌暴露的反应能力存在基因变异，据报道遗传力估计值在0.06至0.18之间。尽管这些估计值幅度适中，但表明通过选择性育种可以提高宿主对牛结核病的抵抗力。尽管进展相对缓慢，但基因进展可以是持续、累积和永久的，从而补充现有的疾病控制措施。重要的是，在牛结核病抗性与其他动物性状之间大多未发现拮抗基因相关性，这表明在育种决策中谨慎纳入前者应不会对牛的生产力产生不利影响。模拟研究表明，基因选择对降低疫情爆发概率或已宣布疫情爆发的持续时间和严重程度具有潜在影响。此外，对牛基因组的研究已确定了多个与牛结核病抗性相关的基因组标记和基因。然而，这些研究的综合结果表明，宿主对牛结核病的抗性是一个复杂的多基因性状，没有单个基因能够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，以充分捕捉多个基因的集体效应，从而为选择性育种计划提供支持。除了提高宿主对牛结核病的抗性外，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的基因变异，并证实如果选择性育种同时考虑宿主抗性和传染性性状，牛结核病的根除将加速。总之，关于牛结核病遗传学的研究活动已产生知识和见解，以支持选择性育种作为控制和根除该疾病的一项额外措施。
