Understanding Heat Stress in Cattle

Texas heat can be brutal, often accompanied by lingering drought conditions. It's crucial to remember that heat stress is a significant concern during this time for Texas and many other parts of the U.S. While we can't control the weather, we can take measures to ensure our cattle don't bear the full brunt of the heat.

What is Heat Stress and What Causes it?

Heat stress in cattle occurs when the animal’s heat load exceeds its capacity to dissipate heat. Cattle primarily dissipate heat through respiration, skin surface evaporation, and to a lesser extent, sweating. Factors contributing to heat stress include high temperatures, humidity, solar radiation, and lack of air movement. According to the Texas A&M AgriLife Extension, “Heat stress in cattle is a result of a combination of environmental factors, such as temperature, humidity, solar radiation, and air movement, that overwhelm the animal's ability to cool itself” .

Effects of Heat Stress

Heat stress has profound effects on cattle, ranging from mild discomfort to severe physiological issues and even death. Signs of heat stress include increased respiration rate, drooling, reduced feed intake, and lethargy. Prolonged exposure can lead to decreased milk production, poor growth rates, reproductive issues, and weakened immune function. A study by the University of Minnesota Extension found that “Heat stress negatively impacts dairy cows’ milk production, reproduction, and overall health, leading to significant economic losses in the dairy industry”.

The cumulative economic impact of heat stress on the cattle industry in Texas can be substantial. A study conducted by Texas A&M University estimated that the annual economic losses due to heat stress in cattle across the southern United States, including Texas, exceeds $370 million.

Combating Heat Stress

Reducing heat stress involves a combination of management practices. Here are several considerations:

1. Shade: Providing shade is one of the most effective ways to reduce heat stress. Trees, shade cloths, and constructed shelters can significantly lower the temperature in shaded areas. According to Dr. Fred Martz from the University of Missouri, “Providing shade can reduce the heat load on cattle by up to 30%” .
2. Adequate Water Supply: Ensuring that cattle have access to clean water is essential. Water intake increases significantly during hot weather, and dehydration can exacerbate heat stress. The University of Nebraska-Lincoln Extension advises that “Cattle need to drink at least twice as much water during periods of heat stress. Providing fresh, cool water can help maintain their hydration and body temperature” .
3. Feeding Times: Adjusting feeding times and diet can also help manage heat stress. Feeding during cooler parts of the day, such as early morning or late evening, can reduce the metabolic heat produced from digestion. A study from the University of Georgia found that “Feeding cattle during cooler periods of the day and providing high-quality forage can reduce the heat load and improve nutrient utilization” .

Heat stress can be a challenge in Texas, with far-reaching effects on ultimate productivity. As temperatures remain high during the summer months, proactive measures are essential for sustaining cattle health and productivity. By staying informed and adopting best practices, Texas ranchers can safeguard their overall herd health and pocketbook.

References

1. Texas A&M AgriLife Extension. "Managing Heat Stress in Cattle." Retrieved from agrilifeextension.tamu.edu.
2. University of Minnesota Extension. "Heat Stress in Dairy Cattle." Retrieved from extension.umn.edu.
3. University of Missouri Extension. "Providing Shade for Cattle." Retrieved from extension.missouri.edu.
4. University of Nebraska-Lincoln Extension. "Heat Stress and Cattle Water Needs." Retrieved from extension.unl.edu.
5. University of Florida. "Heat Stress in Cattle: Mitigation and Management." Retrieved from edis.ifas.ufl.edu.
6. University of Georgia. "Feeding Strategies for Heat-Stressed Cattle." Retrieved from extension.uga.edu.
7. Dr. Terry Mader, University of Nebraska. "Heat Stress Monitoring and Intervention." Retrieved from extension.unl.edu.