High temperature and humidity


Source: National Farm Animal Care Council, Code of Practice for the Care and Handling of Beef Cattle Section 1.1.1

Cattle are generally able to tolerate low temperatures better than high temperatures. Humidity levels and ventilation affect an animal’s ability to cope with heat stress. Extreme heat is generally more stressful to cattle early in the summer season before they have had a chance to acclimate to the increased temperatures (3).

Signs of heat stress in cattle include (4-6):

  • open-mouth panting with tongue protruding
  • laboured breathing
  • drooling or froth around the mouth.

Cattle are at risk of heat stress when combined temperature and humidity exceed a Humidex value of 40. However, factors such as shade, air movement and length of exposure all influence the impact of high Humidex values on cattle (3).

Heat stress can lead to reductions in feed intake, weight gain, reproductive efficiency and milk production. Severe heat stress may result in illness and death (7).

Water requirements are greater during hot weather.


  1. When cattle are showing signs of heat stress, consider the following strategies (3):
    • provide shade
    • avoid handling cattle
    • feed cattle at dusk or dawn
    • moisten the ground in part of the pen
    • sprinkle cattle with water.


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