Genetic strategies aimed at improving general immune competence (IC) have the potential to reduce the incidence and severity of disease in beef production systems, with resulting benefits of improved animal health and welfare and reduced reliance on antibiotics to prevent and treat disease. Implementation of such strategies first requires that methodologies be developed to phenotype animals for IC and demonstration that these phenotypes are associated with health outcomes. We have developed a methodology to identify IC phenotypes in beef steers during the yard weaning period, which is both practical to apply on-farm and does not restrict the future sale of tested animals. In the current study, a total of 838 Angus steers, previously IC phenotyped at weaning, were categorized as low (n = 98), average (n = 653), or high (n = 88) for the IC phenotype. Detailed health and productivity data were collected on all steers during feedlot finishing, and associations between IC phenotype, health outcomes, and productivity were investigated. A favorable association between IC phenotype and number of mortalities during feedlot finishing was observed with higher mortalities recorded in low IC steers (6.1%) as compared with average (1.2%, P < 0.001) or high (0%, P = 0.018) IC steers. Disease incidence was numerically highest in low IC steers (15.3 cases/100 animals) and similar in average IC steers (10.1 cases/100 animals) and high IC steers (10.2 cases/100 animals); however, differences between groups were not significant. No significant influence of IC phenotype on average daily gain was observed, suggesting that selection for improved IC is unlikely to incur a significant penalty to production. The potential economic benefits of selecting for IC in the feedlot production environment were calculated. Health-associated costs were calculated as the sum of lost production costs, lost capital investment costs, and disease treatment costs. Based on these calculations, health-associated costs were estimated at AUS$103/head in low IC steers, AUS$25/head in average IC steers, and AUS$4/head in high IC steers, respectively. These findings suggest that selection for IC has the potential to reduce mortalities during feedlot finishing and, as a consequence, improve the health and welfare of cattle in the feedlot production environment and reduce health-associated costs incurred by feedlot operators.

中文翻译：

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安格斯牛免疫能力表型与饲养场健康和生产力之间的关联

旨在提高一般免疫能力 (IC) 的遗传策略有可能降低牛肉生产系统中疾病的发生率和严重程度，从而改善动物健康和福利并减少对抗生素预防和治疗疾病的依赖。实施此类策略首先需要开发用于 IC 表型动物的方法，并证明这些表型与健康结果相关。我们开发了一种方法来在院子断奶期间识别阉牛中的 IC 表型，这既适用于农场，又不限制未来测试动物的销售。在目前的研究中，共有 838 头安格斯公牛，之前在断奶时有 IC 表型，IC 表型分为低 (n = 98)、平均 (n = 653) 或高 (n = 88)。在饲养场整理期间收集了所有阉牛的详细健康和生产力数据，并研究了 IC 表型、健康结果和生产力之间的关联。观察到 IC 表型与饲养场整理期间的死亡率之间存在良好的关联，低 IC 阉牛 (6.1%) 记录的死亡率高于平均值 (1.2%, P < 0.001) 或高 (0%, P = 0.018) IC 引导。低 IC 阉牛（15.3 例/100 只动物）的疾病发病率最高，平均 IC 阉牛（10.1 例/100 只动物）和高 IC 阉牛（10.2 例/100 只动物）的发病率相似；然而，组间的差异并不显着。没有观察到 IC 表型对平均日增重的显着影响，这表明选择改进的 IC 不太可能对生产造成重大损失。计算了在饲养场生产环境中选择 IC 的潜在经济效益。健康相关成本计算为生产成本损失、资本投资成本损失和疾病治疗成本的总和。根据这些计算，低 IC 阉牛的健康相关成本估计为 103 澳元/头，平均 IC 阉牛为 25 澳元/头，高 IC 阉牛为 4 美元/头。这些研究结果表明，IC 的选择有可能降低饲养场整理期间的死亡率，从而改善饲养场生产环境中牛的健康和福利，并降低饲养场经营者产生的与健康相关的成本。健康相关成本计算为生产成本损失、资本投资成本损失和疾病治疗成本的总和。根据这些计算，低 IC 阉牛的健康相关成本估计为 103 澳元/头，平均 IC 阉牛为 25 澳元/头，高 IC 阉牛为 4 美元/头。这些研究结果表明，IC 的选择有可能降低饲养场整理期间的死亡率，从而改善饲养场生产环境中牛的健康和福利，并降低饲养场经营者产生的与健康相关的成本。健康相关成本计算为生产成本损失、资本投资成本损失和疾病治疗成本的总和。根据这些计算，低 IC 阉牛的健康相关成本估计为 103 澳元/头，平均 IC 阉牛为 25 澳元/头，高 IC 阉牛为 4 美元/头。这些研究结果表明，IC 的选择有可能降低饲养场整理期间的死亡率，从而改善饲养场生产环境中牛的健康和福利，并降低饲养场经营者产生的与健康相关的成本。分别。这些研究结果表明，IC 的选择有可能降低饲养场整理期间的死亡率，从而改善饲养场生产环境中牛的健康和福利，并降低饲养场经营者产生的与健康相关的成本。分别。这些研究结果表明，IC 的选择有可能降低饲养场整理期间的死亡率，从而改善饲养场生产环境中牛的健康和福利，并降低饲养场经营者产生的与健康相关的成本。