模拟加拿大霍尔斯坦牛的生产特征的耐热度
I L Campos1, R E Jahnel1, F Miglior2
1Centre for Genetic Improvement of Livestock, Department of Animal Biosciences, University of Guelph, Guelph, N1G 2W1 Ontario, Canada.
Journal of dairy science
|July 20, 2025
概括
这项研究比较了两种模型,用于估计乳牛的耐热性. 两种模型都有效地识别了耐热性具有高遗传优势的公牛,在繁殖价值排名中显示出最小的差异.
科学领域:
- 动物遗传学动物遗传学
- 乳制品科学 乳制品科学
- 环境压力生物学
背景情况:
- 热应激显著影响乳牛的生产力和福利.
- 目前用于评估耐热度的方法通常使用一个共同的温度-湿度指数 (THI) 值,忽视个体变化.
- 使用线性热应力函数 (HSf) 的反应规范模型是标准的,但可能无法捕获细微的个体反应.
研究的目的:
- 用Legendre多项式 (LP) 模型来估计耐热性的遗传参数和育种值,这些模型可以解释个别THI值的变化.
- 将这些LP模型的估计与传统HSf模型的估计进行比较.
- 评估不同建模方法对加拿大霍尔斯坦牛耐热性遗传评估的影响.
主要方法:
- 利用了来自加拿大的300791头等牛的测试日记录,与当地气象数据联系起来.
- 与标准热应力函数 (HSf) 模型进行线性,二次和立方列德多项式 (LP) 模型的比较.
- 使用平均平方误差 (MSE) 评估模型性能,并通过THI梯度分析参数估计.
- 使用斯皮尔曼等级相关性,LP和HSf模型之间的耐热性和牛奶生产特征的相关繁殖值 (EBV).
主要成果:
- 二次式LP模型在THI梯度上表现良好.
- 对于LP和HSf模型之间的公牛EBV,Spearman等级相关性对于整体耐热性是很高的 (大于0.97).
- 热应激下脂肪,蛋白质和牛奶产量的等级相关性是相当大的 (分别为0.97,0.95和0.86),即使在比较前10%的公牛时也是如此.
结论:
- 莱根德多项式和传统的HSf模型都能有效地识别出耐热性优越遗传优势的公牛.
- 模型的选择并没有实质性地改变用于遗传评估的公牛的排名.
- 这些发现支持在加拿大乳制品热耐受性遗传评估中继续使用这些模型.
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