Heat stress in cattle is a critical concern for producers, particularly in the warmer months. As temperatures rise, so does the risk of heat stress, which can significantly affect cattle’s health, productivity and welfare. This article delves into the causes, impacts and management strategies for heat stress in cattle.
Understanding heat stress in cattle
Heat stress occurs when an animal’s heat load exceeds its capacity to lose heat, leading to increased body temperature and stress. Factors such as high temperatures, humidity, solar radiation and lack of wind contribute to heat stress. Cattle with darker coats absorb more solar radiation, exacerbating the problem. Furthermore, cattle produce heat through digestion, especially after eating, which can add to their thermal load during hot weather.
Water management
The significance of water for cooling cattle cannot be overstressed. Cattle’s water needs can double or even triple as temperatures rise. It’s not just about quantity but also about quality and accessibility. Water tanks should be clean and the water should be cool, as warm water is less appealing and less effective at heat mitigation. By increasing the number of accessible points for water consumption, cattle can maintain hydration more effectively, which is crucial for their ability to regulate body temperature and stay healthy during heat events.
Add more water tanks or dam one to two sections of your feedbunk to create more available water during extreme heat. Cattle should have 2 to 4 inches of water space available. Additionally, be sure that the recharge rate is sufficient to prevent waterers from running dry. With more water consumption comes greater urination and greater excretion of some minerals, so work with your nutritionist to make sure you are meeting your dietary mineral requirements during periods of heat stress.
The role of shade and shelter
Providing adequate shade and shelter can significantly reduce the thermal stress on cattle. It provides a respite from direct sunlight, which can significantly reduce the temperature that cattle are exposed to during the hottest parts of the day. This can be achieved through natural means like trees or by constructing shelters. Structures that offer protection from direct sunlight can lower surface and air temperatures around cattle, making it easier for them to stay cool. Strategic placement and design of these structures ensure they are used effectively by the herd during peak heat hours. Cattle require 20 to 40 square feet of shade to be comfortable, and if using an artificial shade structure, it should be at least 8 feet high to ensure effective air movement beneath the ceiling.
Feed in the evening
Cattle generate internal heat through digestion, which can be managed by adjusting feeding times to align with cooler external temperatures, typically by feeding in the evening. This strategy not only prevents cattle from overheating but also corresponds to their natural grazing patterns, where they forage more during cooler times, such as morning and evening hours. By feeding approximately 70% of their daily feed two to four hours after the day’s peak temperatures, internal heat production from digestion peaks during cooler evening temperatures, enhancing cattle comfort and feeding efficiency.
To optimize this approach, evening feedings can be scheduled between 4 p.m. and 6 p.m., with the option to distribute 100% of the daily feed in the evening, or split it into 30% in the morning and 70% in the evening. This timing shifts the heat of fermentation, caused by feed digestion, to the night, helping cattle maintain their feed intake during heat waves. It also addresses the issue of feed going out of condition due to lower afternoon appetite, ensuring cattle have access to feed when they are most inclined to eat, particularly before sunrise in the summer. This method ensures that feedbunks are efficiently utilized, avoiding waste and supporting optimal cattle health and productivity.
Nutrient adjustments
To enhance cattle health and resilience during periods of heat stress, incorporating an additional 0.5 ounce per head of potassium chloride or potassium carbonate into their feed for a duration of four to five days is advisable. Potassium serves as an essential element in the regulation of thermoregulation and hydration within cattle. By supplementing their diet with potassium during times of elevated temperatures, it becomes possible for cattle to regulate their internal body temperatures more effectively. This supplementation aids in maintaining a balanced electrolyte level, which is vital for their physiological well-being when under stress. The role of potassium in supporting muscle and nerve function further underscores its importance, ensuring that cattle remain active and healthy even in challenging environmental conditions.
Moreover, during such heat stress events, it’s recommended not to transition cattle to a new ration but rather to continue feeding them their current ration. During extreme heat stress events, it’s beneficial to reduce their feed intake by 25% to minimize the generation of internal metabolic heat. This strategic adjustment helps in mitigating the additional thermal burden on the cattle, allowing them to better cope with the heat by reducing the energy expended on digestion, thereby conserving more energy for essential bodily functions.
Implementing evaporative cooling systems
Evaporative cooling systems, including misters and sprinklers, offer a quick solution to alleviate heat stress for cattle by reducing both their body temperature and the ambient air temperature. These cooling methods are especially effective in arid regions where the added moisture can swiftly evaporate, leading to a significant cooling impact without substantially raising humidity levels. For optimal effectiveness, sprinklers must emit water droplets that are large enough to penetrate the cattle’s hair coat and wet the skin, since merely wetting their hair can lead to insulation rather than cooling. Furthermore, it is important to regulate the amount of water used to prevent excessive mud formation. Excessive mud can adhere to the cattle, forming an unwanted insulating layer that can hinder the cooling process.
Best practices for handling and movement
Minimizing stress from handling and movement during heat waves is crucial because handling can exacerbate heat stress. Activities such as receiving, shipping or moving cattle should be conducted during the coolest parts of the day – ideally before 10 a.m. – to avoid the peak heat. This reduces the additional stress on cattle and helps prevent exacerbation of heat stress conditions. Additionally, wait to handle cattle four to six hours after sundown to give them adequate time to cool down. Try to avoid working cattle on days of extreme heat unless absolutely necessary.
Remove nonpermanent windbreaks
Windbreaks are necessary during colder months, but during a heat wave, they can impede natural air movement. Removing these barriers can significantly improve airflow, which is vital for natural cooling through convection. This increased air movement helps dissipate heat away from the cattle’s bodies, contributing to their overall cooling. Cattle housed in confined buildings or barns can utilize fans to improve air circulation.
Fly control
When cattle face the dual challenges of heat stress and fly infestations, their behaviors reflect an attempt to combat these stressors simultaneously. To fend off flies, cattle might engage in increased tail flicking, head shaking and skin twitching. These actions, while effective against flies, can expend additional energy that could exacerbate heat stress by increasing their metabolic rate. Furthermore, cattle may seek shade or cluster together in areas with fewer flies, which can inadvertently increase their body heat due to the close proximity to other animals. The presence of flies often disrupts beneficial cooling behaviors, causing cattle to move around more than usual, which can further elevate their stress levels and body temperature. Consider utilizing fly control options such as tags or a feed-through fly control product. Consult with your nutritionist to discuss the best options for your herd.
Vasodilator inclusion
Feeding vasodilators can potentially promote blood vessel expansion, improving blood flow, nutrient delivery and heat dissipation. Consult with a livestock nutrition consultant to ensure its suitability for your herd.
Conclusion
Managing heat stress in cattle involves a multifaceted approach that prioritizes water management, provides shade and shelter, adjusts nutrition, utilizes evaporative cooling systems and follows best practices for handling and movement. By understanding the causes and impacts of heat stress and employing these advanced mitigation strategies, beef cattle producers can ensure the welfare of their herds and maintain productivity throughout the hot summer months.
