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模拟热应激,料摄入量和与非哺乳乳乳母牛分娩相对的一天之间的关系

V C Souza¹, L E Moraes¹, J E P Santos²

¹Department of Animal Science, University of California, Davis, Davis, CA 95616.

Journal of dairy science

|September 7, 2023

概括

热应激显著降低了怀孕乳牛的干物质摄入量 (DMI). 蒸发式冷却系统减轻了这些减少,特别是随着怀孕的进展和热负荷的增加,有助于农场的利能力.

科学领域:

动物科学动物科学
乳制品营养乳制品营养
环境生理学环境生理学

背景情况:

干旱期间的热应激 (HS) 对奶牛的福利,健康,干物摄入量 (DMI) 和随后的牛奶产量产生负面影响.
这些影响降低了奶牛场的利能力,强调了需要有效的管理策略.

研究的目的:

模拟孕妇,非哺乳乳乳母奶牛体验热应激的DMI变化.
为了评估蒸发式冷却系统在晚期干旱期间对DMI的影响.

主要方法:

使用了244只孕期,非哺乳乳乳母牛的数据库,记录了相对于分娩 (DRC) 的DMI从-42天到-1天.
采用了通用的添加混合效应模型来分析DMI与热应力 (温度湿度指数,THI) 和DRC的关系.
使用微分方程估计DMI变化,比较带有和没有蒸发冷却的奶牛.

主要成果:

与冷却的奶牛相比,未冷却的奶牛的DMI减少了1.30公斤/天,直肠温度增加了0.22°C.
随着THI的增加,DMI下降,非冷却奶牛的减少更为明显.
在未冷却的奶牛和冷却的奶牛 (-14 DRC) 中,DMI的下降较早开始 (-30 DRC),在使用冷却或在较冷的月份分娩的奶牛中强度降低.

结论:

蒸发式冷却系统有效地维持了热应激孕产奶牛的DMI.
结合环境变量和怀孕阶段的预测模型可以改善饮食配方的DMI估计.
这些模型可以指导乳制品营养学家实施及时的饮食策略,以减轻HS诱导的DMI减少.

关键词:

热应激是一种热应激.模型模型模型模型过渡期是一个过渡期.

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