Heat stress is not a new concept for the beef industry. For decades, the environment has been recognized as a factor in an animal’s ability to maximize production. Cattle are at greater risk for heat stress when air temperature and humidity are increased, especially when overnight temperatures remain high.
In recent years, there has been an increase in the frequency of heat events, and predictions for this summer are no different. Cattle have some physiological and behavioral changes to help stay cool, but these mechanisms may not be enough during prolonged periods of heat. Producers should start to consider management strategies to help mitigate heat stress this summer early – before the heat arrives.
How cattle respond to heat stress
During heat events, cattle undergo several physiological changes to help manage elevated body temperatures. Like other animals and people, cattle can dissipate heat through evaporative cooling, primarily through sweating and panting. When sweat or moisture on the skin evaporates, heat energy is pulled away from the body’s surface, helping to lower body temperature.
Cattle are relatively inefficient sweaters, and sweating rates can vary based on breed, hair coat, sun exposure, humidity, and airflow. In addition to sweating, cattle rely heavily on panting, which provides evaporative cooling through the respiratory tract.
As breathing rate increases, moisture evaporates from the lining of the lungs and airways, allowing heat to be released from the body. While effective, excessive panting and increased breathing rate are important indicators that cattle are struggling to cope with heat and may need additional support.
Cooling strategies that Support cattle comfort
Producers can enhance cooling by using fans and sprinklers or misting systems. Fans increase the airflow over the skin’s surface, which removes heat directly through convection and improves evaporative cooling by speeding up moisture evaporation.
Sprinkler or misting systems use evaporative cooling to reduce body temperature and pen surface temperature. For best results, cattle should be wet quickly and then allowed time to dry before the system cycles on again.
Sprinklers are not ideal for every system, as their use increases humidity, which can worsen heat stress. Adequate airflow is essential for these systems to provide benefit to cattle during heat events. It is also important to consider pen type and drainage to ensure excess water does not lead to muddy pen conditions. Without proper airflow and drainage, sprinklers can worsen heat stress instead of relieving it.
The role of shade and pen design in heat mitigation
To help mitigate heat stress, cattle will reduce their activity and seek shade to avoid heat from solar radiation.
- Providing shaded areas within pens can help lower body temperature.
- Shade structures should provide 20 to 40 square feet of shade per animal.
- Overcrowding in the shaded area can decrease its effectiveness by limiting airflow.
- Shade structure height is also important. Structures less than seven feet tall can restrict airflow.
- Adequate airflow is critical, as still air can trap heat and make the shade less effective.
How heat stress impacts feeding behavior and intake
Cattle will also change their feeding behavior during a heat event in response to overall heat stress, as increased body temperature and metabolic heat load, suppress appetite.
During heat events, cattle will consume smaller, more frequent meals and eat at cooler times of the day, such as in the evening or early morning; however, overall dry matter intake typically declines.
Adjusting feed delivery time can help producers manage heat production from fermentation and encourage feed intake during cooler parts of the day. Feeding in the evening or delivering 70% of the diet in the afternoon for operations that feed twice daily, can help shift internal heat production to cooler nighttime hours when environmental temperatures are lower.
Nutrition strategies to maintain performance in heat
During heat events reduced intake can limit energy consumption, leading to reductions in performance. Increasing dietary energy density and feeding higher quality, more digestible forages can help meet the energy needs while reducing heat produced during digestion.
Feed additives that support cattle during heat stress
Feed additives are an option to help maintain performance by supporting dry matter intake, assisting cooling mechanisms, and reducing digestive challenges such as leaky gut and hindgut inflammation.
NutriVantage® for beef, can be used as a tool to help support intake, rumen function and overall performance during extreme heat events. In a field trial during extreme summer heat, cattle fed NutriVantage maintained a 1.9 lb per day dry matter intake advantage over control cattle. This highlights how targeted feed additives can help cattle continue to eat and perform during heat stress.
Another additive that is beneficial during heat stress is BetaMOS. Heat stress can challenge gastrointestinal function and decrease gut barrier integrity. BetaMOS contains mannan oligosaccharides and β-glucans derived from yeast cell wall, which bind pathogenic bacteria in the hindgut and limit their ability to interact with host cells. By supporting gut health and helping regulate the immune response, BetaMOS can aid cattle during physiological stressors, such as prolonged heat events.
Plan ahead to protect performance this summer
Heat stress is a predictable challenge, but its negative impacts on cattle performance can be reduced through thoughtful management and planning. By understanding how cattle respond to heat and implementing strategies to support feed intake and cooling, producers can help cattle maintain performance during extreme conditions during summer months. Now is the time to start preparing for heat events so you can respond proactively and improve health and productivity during extreme heat events.
