Heat stress in the cattle herd may be a concern during the warmest months of the year in the southeast U.S. Unlike humans, cattle get rid of excess heat in their system through breathing and panting more than sweating. The combination of high temperatures and high relative humidity, along with age, hair coat color and length, and nutritional status may influence how animals respond to heat stress. The following provides some measures we can take to minimize effects on the cattle herd:
1. Handle cattle early in the morning. Plan to handle cattle early in the morning (beginning at daylight), with the goal of being done around 10 a.m. While this may be easier said than done, processing cattle increases the animal’s core body temperature and puts them at risk for experiencing heat stress earlier in the day. This translates to more time spent in the shade after working. Use low-stress handling techniques to minimize stress during handling.
2. Establish a grazing management plan. Rotate cattle to new pastures at night rather than in the morning. While this may seem to counter the above statement about when to work cattle, moving cattle in the early evening also coincides with the time of day when air temperatures are coming down. Cattle often graze in the early morning or late evening, so moving to a new pasture area in the early evening may encourage animals to actively graze as the daytime temperature begins to decrease.
3. Check water sources. Providing access to an adequate supply of clean, cool water is important to help maintain the internal temperature of cattle within the normal range. In the warmest months of the year, mature cattle can consume up to 2 gallons of water per 100 pounds of bodyweight. That is between 25 and 30 gallons of water per head per day needed for the majority of our beef cattle in the Southeast. Careful monitoring of water sources is critical during these months to ensure an ample, algae-free supply for the beef cattle herd.
4. Think about animal transport and timing. If you are hauling calves to be sold during this time of the year, avoid overcrowding on stock trailers and consider transport in the morning. Calves lose an estimated 1% of their bodyweight per hour due to shrink loss in the first three to four hours after a major stressor has been induced such as weaning, hauling, a sudden change in environment and marketing.
