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Use of the Comprehensive Climate Index to estimate heat stress response of grazing dairy cows in a temperate climate region

机译：利用综合气候指数来估算温带气候区放牧奶牛的热应激反应

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摘要

The aim of the study was to assess the effect of the summer thermal environment on physiological responses, behaviour, milk production and its composition on grazing dairy cows in a temperate climate region, according to the stage of lactation. Twenty-nine Holstein Friesian multiparous cows were randomly selected and divided into two groups, according to the days in milk, as mid-lactation (99 to 170 d in milk, n = 15) and late lactation (225 to 311 d in milk, n = 14). The comprehensive climate index (CCI) was used to classify the hour of each day as thermoneutral or heat stress, considering a threshold value of CCI of 20°C. Data were collected for 16 d (summer 2017) and analysed as a completely randomized 2 × 2 factorial arrangement with repeated measurements over time. Vaginal temperature increased with CCI ≥ 20°C. Respiration rates were dependent on the thermal condition, regardless of days in milk. There was an interaction between the time of day and the CCI category for activity and rumination. Grazing activity decreased by 17.6% but lying down, standing, and shaded animals increased by 1.6, 9.8, and 6.3% respectively when CCI ≥ 20°C. Over 80% of cows presented a panting score ≥1. However, milk production and composition (fat, protein, and lactose concentrations as well as somatic cell count) were not affected by the thermal condition, although there was a numerical (non-significant) decrease in afternoon milk protein concentration on days with CCI ≥ 20°C, while urea in milk increased. In conclusion, thermal condition challenged grazing dairy cows' behaviour and physiology independent of the stage of lactation but had little or no effect on milk production.
机译：根据哺乳期的说法，该研究的目的是评估夏季热环境对在温带气候区放牧奶牛的生理反应，行为，牛奶产量及其组合物的影响。根据牛奶的日子，随机选择二十九个荷斯坦弗里斯多体奶牛并分为两组，作为中泌乳（99至170 d在牛奶中，n = 15）和晚期哺乳（225至311d牛奶中， n = 14）。考虑到20℃的CCI的阈值，综合气候指数（CCI）用于将每一天的小时分类为热源或热应激。收集数据16d（2017年夏季），并作为完全随机化的2×2因子布置，随着时间的推移重复测量。阴道温度随CCI≥20°C而增加。无论牛奶中的天数如何，呼吸率都依赖于热条件。在一天中的时间和CCI类别之间存在相互作用和活动和谣言之间的互动。放牧活动减少了17.6％，但躺着，静置和阴影动物分别在CCI≥20°C时增加1.6,9.8和6.3％。超过80％的奶牛呈现喘息分数≥1。然而，牛奶生产和组合物（脂肪，蛋白质和乳糖浓度以及体细胞计数）不受热条件的影响，尽管午后牛奶蛋白质浓度有数值（非显着）降低，CCI≥ 20°C，牛奶中的尿素增加。总之，热情挑战撒母奶牛的行为和生理学，独立于哺乳期，但对牛奶生产几乎没有影响。

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  • 来源
    《Journal of dairy research》 |2021年第2期|154-161|共8页
  • 作者

    Rodrigo A. Arias; Cynthia Delgado; Juan Pablo Keim; Monica Gandarillas;

  • 作者单位

    Facultad de Ciencias Agrarias y Alimentarias Instituto de Production Animal Universidad Austral de Chile Valdivia Chile Facultad de Ciencias Agrarias y Alimentarias Centro de Investigation de Suelos Volcanicos Universidad Austral de Chile Valdivia Chile;

    Escuela de Graduados Facultad de Ciencias Agrarias y Alimentarias Universidad Austral de Chile Valdivia Chile;

    Facultad de Ciencias Agrarias y Alimentarias Instituto de Production Animal Universidad Austral de Chile Valdivia Chile;

    Facultad de Ciencias Agrarias y Alimentarias Instituto de Production Animal Universidad Austral de Chile Valdivia Chile;

  • 收录信息 美国《科学引文索引》(SCI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

    Animal welfare; grazing; heat stress; pantig scores; respiration rate;

    机译：动物福利;放牧;热应激;音节分数;呼吸率;

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