What are the signs of heat stress in dairy cows?

How to recognise heat stress in cows?

Clinical signs of heat stress in cattle are

  • Panting
  • Drooling
  • Milk leakage
  • A drop in milk production
  • Standing up for long periods of time

What are the consequences of heat stress in cattle?

Apart from a drop in milk production and a reduction of fertility, heat stress in dairy cows has a number of other negative effects. Heat stress in cattle increases the risk of developing mastitis80. If heat stress in dairy cows is present, animals in a herd group together in shaded areas of fields. The ground soon gets poached and contaminated with mastitis pathogens, which increases the risk of environmental mastitis in heat-stress cows.

Similar effects can be seen in housed heat stress dairy cows if they congregate and lie in inappropriate places. Heat stress in cattle also results in a higher percentage of lameness, as an increase of the THI leading to heat stress in dairy cows results in an increase of standing time and a decrease of resting time

Heat stress in cows results in an increase of mortality. Lastly, during the dry cow period, dairy cow heat stress results in a lower birth weight of calves and a reduced milk yield in the next lactation

In case of risk for heat stress in cattle, ensure sufficient shade is available to all animals. If there is not enough space for all animals, the high ranking cows in the group will occupy all space in the shade and the animals low in rank will be exposed to direct sunlight continuously increasing the risk of heat stress in cows.