Genetics of tuberculosis in Irish Holstein-Friesian dairy herds
Genetics of tuberculosis in Irish Holstein-Friesian dairy herds
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DOI：
10.3168/jds.2008-1848
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发表时间：
2009-07-01
影响因子：
3.5
通讯作者：
Berry, D. P.
中科院分区：
文献类型：
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作者：
Bermingham, M. L.;More, S. J.;Berry, D. P.
目前缺乏关于奶牛结核病易感性遗传参数的信息。牛分枝杆菌是牛结核病的主要病原体。本研究的目的是量化的遗传变异之间存在的爱尔兰荷斯坦奶牛群的易感性M。牛传染病对15，182头母牛和8，104头小母牛进行了单次皮内比较结核菌素试验（SICTT）。牛暴露和假定感染）记录，从2002年11月1日至2005年10月31日，可用于纳入分析。从屠宰场观察到的尸体结核病病变的数据也可纳入分析。唯一保留的动物是在至少2只动物显示感染证据的事件期间存在于畜群中的动物;这确保了暴露于M的高可能性。牛线性动物模型，公畜和动物阈值模型被用来估计方差分量的敏感性M。牛纯化蛋白衍生物（PPD）的反应性，并确认M.牛传染病阈值公畜模型的遗传力估计值偏高，因为忽略了母畜-子代间的相关性。阈值动物模型产生的遗传力估计值为0.14的奶牛和0.12的小母牛的易感性M。牛PPD反应性为0.18，奶牛中确认的M.牛感染易感性因此，爱尔兰奶牛对M.牛传染病线性和阈值动物模型的父系等级相似，表明任一模型均可用于分析对M的敏感性。牛PPD反应性。一个有利的遗传相关性接近统一的观察之间的易感性确认M。牛感染和M. Bovis-PPD反应性，表明对M.牛-PPD反应性将间接降低对确诊的M的易感性。牛传染病来自国家结核病根除计划的数据可以常规地用于估计对M.牛传染病
Information is lacking on genetic parameters for tuberculosis (TB) susceptibility in dairy cattle. Mycobacterium bovis is the principal agent of tuberculosis in cattle. The objective of this study was to quantify the genetic variation present among Irish Holstein-Friesian dairy herds in their susceptibility to M. bovis infection. A total of 15,182 cow and 8,104 heifer single intradermal comparative tuberculin test (SICTT, a test for M. bovis exposure and presumed infection) records from November 1, 2002, to October 31, 2005, were available for inclusion in the analysis. Data on observed carcass TB lesions from abattoirs were also available for inclusion in the analysis. The only animals retained were those present in a herd during episodes in which at least 2 animals showed evidence of infection; this ensured a high likelihood of exposure to M. bovis. Linear animal models, and sire and animal threshold models were used to estimate the variance components for susceptibility to M. bovis-purified protein derivative (PPD) responsiveness and confirmed M. bovis infection. The heritability estimates from the threshold sire models were biased upward because the relatedness between dam-daughter pairs was ignored. The threshold animal model produced heritability estimates of 0.14 in cows and 0.12 in heifers for susceptibility to M. bovis-PPD responsiveness, and 0.18 in cows for confirmed M. bovis infection susceptibility. Therefore, exploitable genetic variation exists among Irish dairy cows for susceptibility to M. bovis infection. Sire rankings from the linear and threshold animal models were similar, indicating that either model could be used for the analysis of susceptibility to M. bovis-PPD responsiveness. A favorable genetic correlation close to unity was observed between susceptibility to confirmed M. bovis infection and M. bovis-PPD responsiveness, indicating that direct selection for resistance to M. bovis-PPD responsiveness will indirectly reduce susceptibility to confirmed M. bovis infection. Data from the national TB eradication program could be used routinely to estimate breeding values for susceptibility to M. bovis infection.