雌羊出生子大小和遗传参数估计对雌羊生殖生活特征的影响
L L Hulsman Hanna1, J B Taylor2, P W Holland3
1Department of Animal Sciences, North Dakota State University, Fargo, ND 58108, USA.
Animal : an international journal of animal bioscience
|July 21, 2023
概括
绵羊一生的生产力对利能力至关重要. 虽然选择更大的子大小会增加羔羊数量,但它可能会减少母羊的寿命和稳定性,从而影响基于范围的系统的整体经济回报.
科学领域:
- 动物科学动物科学
- 生殖生物学 生殖生物学
- 量化遗传学 量化遗传学
背景情况:
- 绵羊的寿命生产率直接影响生产者的利能力,美国西部的基于范围的系统的生产寿命比温带地区更短.
- 增加 litter 尺寸一直是以范围为基础的系统中选择的重点,以弥补母羊寿命的减少,但母羊出生 litter 尺寸 (ELSB) 对生产力的影响是不充分研究的.
研究的目的:
- 为了研究母羊出生子大小 (ELSB) 对母羊长寿和稳定性的影响,在广泛的,基于范围的生产系统中.
- 分析这些跨不同品种 (哥伦比亚,Polypay,Rambouillet,Targhee) 和个体品种内的关系.
主要方法:
- 利用跨品种 (n=11,550) 和品种内部 (n=4,398-6,482) 对 1950-2008 年的母羊记录的分析.
- 采用动物模型以限制最大概率估计,包括母羊的出生年份,ELSB (单双,双胞胎,三胞胎),并将品种作为固定效应.
- 研究了长寿 (生产年) 和稳定性 (到7岁的生存概率).
主要成果:
- 长寿和稳定性的遗传概率估计在0.06到0.34之间,较年轻年龄的稳定性估计更高.
- 品种的影响是显著的;与其他品种相比,Polypay羊的生产寿命更短,生存率更低.
- ELSB显著影响了寿命 (60%的分析) 和稳定性 (37%的分析). 在较小的里出生的母羊通常有更长的生产寿命和更高的生存率,特别是在跨品种分析中.
结论:
- 在基于广泛范围的系统中增加母羊的繁殖率 (子大小) 可能会对母羊的生产寿命和存活率产生负面影响.
- 这些发现表明,子大小和母羊的寿命之间存在权衡,需要在育种计划中仔细考虑.
- 这些特征的低遗传性要求对遗传建模进行进一步的研究,包括主导效应和 litter 尺寸相互作用.
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