断奶指数的纵向遗传动态以及对牛犊生产效率的影响
K C Almeida1, A B Bignardi1, M E Z Mercadante2
1Grupo de Melhoramento Animal de Mato Grosso (GMAT), Instituto de Ciências Agrárias e Tecnológicas, Universidade Federal de Rondonópolis (UFR), 78736-900 Rondonópolis, MT, Brazil.
Animal : an international journal of animal bioscience
|January 17, 2024
概括
在肉牛中选择年龄体重可能会影响奶牛的效率. 监测部高度和身体状况得分对于保持断奶效率至关重要,建议制定稳定奶牛体重的策略,同时增加小牛断奶体重.
科学领域:
- 动物育种与遗传学
- 牛肉牛生产 牛肉牛生产
- 量化遗传学 量化遗传学
背景情况:
- 在肉牛中增加年轻年龄体重的选择可能会无意中增加成年牛的体重,增加生产成本.
- 了解生产效率措施和既定育种选择标准之间的相互作用对于优化牛养殖计划至关重要.
- 断奶指数 (WIndex) 是为了提高小牛的断奶体重而开发的,同时目标是牛体重 (BW) 的基因增长为零.
研究的目的:
- 纵向评估断奶指数 (WIndex) 和关键奶牛生长特征之间的遗传相关性:体重 (BW),部高度 (HH) 和身体状况得分 (BCS).
- 调查随着时间的推移,WIndex的潜在变化,这是由于年龄体重 (YW) 的选择造成的.
- 评估不同Nelore牛品种的WIndex,BW,HH和BCS的遗传趋势.
主要方法:
- 采用随机回归模型来估计WIndex,BW,HH和BCS之间的遗传相关性,使用来自三个不同的线条的Nelore奶牛数据.
- 对一条控制线 (NeC) 和两条选择增加年龄体重 (NeS和NeT) 的两条线进行了基因趋势分析.
- 纵向数据允许评估不同年龄段的特征关系和趋势.
主要成果:
- WIndex与BW,HH和BCS之间的遗传相关性通常接近于零或负,这表明选择断奶效率时对奶牛大小和状况的负面影响很小.
- 在所有年龄段 (0.73-0.76) 观察到BW和HH之间存在强烈的阳性遗传相关性,而BW和BCS之间的关系随着年龄的增长而加强.
- 选择为YW (NeS和NeT) 的线路显示WIndex增加,与NeT相比,NeS在BW中表现出更明显的增加,而WIndex的增加不那么显著,这可能是由于长时间选择了YW.
结论:
- 建议监测牛的部高度 (HH) 和身体状况得分 (BCS),以防止断奶效率下降.
- 3岁的年龄对于奶牛的断奶效率至关重要,因为年轻的奶牛仍在成长,并断奶更轻的小牛.
- 通过WIndex稳定牛肉体重,同时提高小牛的断奶体重,提供了一种有前途的策略,以减轻牛肉生产的效率损失.
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