• Corpus ID: 49570248

Heat Stress Effect on Immune Function in Dairy Cattle

@inproceedings{Dahl2017HeatSE,
  title={Heat Stress Effect on Immune Function in Dairy Cattle},
  author={Geoffrey E. Dahl and Robert Joseph Collier},
  year={2017}
}

• G. Dahl, R. Collier
• Published 17 October 2017
• Biology

Environmental factors, particularly heat stress, present challenges to dairy cow productivity and health. In the absence of active cooling, exposure to elevated temperatures and humidity significantly reduce dry matter intake during lactation, and subsequent declines in milk yield can approach 25% depending on the severity and duration of the heat stress (reviewed by West, 2003). Lactating cows make metabolic adaptations which repartition additional energy away from productive purposes such that the actual decline in production exceeds what would be expected based on the lower DMI (Rhoads et al., 2009). Similarly, when dry cows are exposed to heat stress they produce less milk than cooled dry cows in the next lactation, even when both groups are cooled after calving (reviewed in Tao and Dahl, 2013). Dry cows under heat stress consume less feed than cooled cows, but the metabolic adaptations observed in lactating cows are not present (Tao et al., 2012). Despite the significant losses associated with productivity under heat stress, additional negative impacts on the overall health of lactating and dry cows and their calves accrue with exposure to high temperatures and humidity, and those outcomes are the focus of this paper.