Source: Elizabeth Griebel, ANR Extension Intern for Wright, McLeod, and Meeker Counties
Managing heat stress in cattle is an important issue to address, especially this time of the year. The USDA states,” Depending on the species, heat stress can reduce meat and milk production and lower animal reproduction rates.” Many livestock animals experience a decrease in feed intake and rate of weight gain.
Many species of animals encounter a variety of heat stress symptoms. Heat stress affects each livestock species differently, however all experience similar heat stress symptoms. Common symptoms for beef cattle include grouping together, seeking shade, panting, and slobbering. Breeds of beef cattle handle stress differently. Animals at the higher risk are heavy cattle, dark-hided cattle, and cattle with weakened immune systems. Common symptoms for dairy cattle include a decrease in milk production; up to about 2.5 pounds per head per day. An early indicator for heat stress in dairy cattle is panting with their necks extended. As heat stress progresses, cattle become lethargic and appear unsteady.
It is important to know what temperatures bring risk for cattle, and internal temperatures that should be monitored when the temperature and humidity is increasing. As seen on the table provided by the UMN Extension Heat Stress in Dairy Cattle page, mild heat stress can begin as low as 72 degrees F with 50% humidity. Once a cow's body temperature reaches 102.5 to 103 it is important to manage the heat stress before the symptoms become more extreme.
Preventing heat stress allows cattle farmers to help manage their cattle’s body temperature in hot and humid weather. Shade is very important on beef and dairy operations. Make sure there is adequate tree coverage if cattle are on pasture and shade structures in a feedlot setting. Wind speed and sunlight greatly affect the degree of heat stress experienced by cattle.
Many forms of ventilation are available for cattle, tunnel ventilation allows air to be brought in on one end of the barn and exhausts it out on the other. Cross ventilation brings air in on the side of the barn and exhausts it out on the other side. Natural ventilation allows fresh air on both sides of the barn, or fans on one side and open on the other side of the barn.
Other key points for managing heat stress in cattle:
- Have cool, fresh water available at all times
- Providing adequate shade with a building or tree cover
- Work with a nutritionist to manage feed changes with increased temperatures, as heat stress increases the energy required for physiological maintenance increases
- Cooling cattle with sprinklers and misters if it works with your facilities
- Considering maximizing ventilation in confinement facilities and/or utilizing natural ventilation and fans
- Limit the handling of cattle in high temperatures and humidity. If animals need to be processed, complete all necessary tasks in the early, cooler times of the day. Avoid handling cattle late in the evening or overnight as the cattle have not yet released the heat that they have accumulated during the day.
- Heat stress affects all ages of cattle not just older, more mature cows
For more information on prevention and managing cattle heat stress, please refer to the managing heat stress in feedlot cattle and heat stress in dairy cattle articles.