Seasonal changes and unpredictable weather cannot be avoided when it comes to beef cattle production – but they can be anticipated and managed effectively. Heading into warmer months, heat stress in beef cattle becomes a major concern for many cow/calf producers and feedyard operators. Understanding the biological impact of heat stress, knowing how to spot it and taking preventative action are all ways to protect animal wellbeing and profitability.
What is Heat Stress in Beef Cattle?
As a rule of thumb, if the Temperature Humidity Index (THI) is above 80, beef cattle are likely to experience heat stress. However, the likelihood of heat stress can change with weather events like precipitation or temperature variation such as warm nights. Almost all outdoor environments can be conducive to heat stress at some point during the year.
Signs of heat stress in cattle:
- Decreased feed intake
- Higher respiration rate
- Labored or open-mouthed breathing
- Excessive slobber
- Bunching together
- More time standing and restlessness
Upon the onset of heat stress, cattle experience a decrease in dry matter intake, which has been hypothesized as a method to help reduce metabolic heat. Changes in blood flow, oxygen and energy availability are also taking place inside the animal. Together, these biological reactions lead to a decline in health and performance.
When cattle are under heat stress, blood flow is diverted from visceral tissue — which lines the blood vessels, stomach, digestive tract and other internal organs — to the skin, which allows for heat dissipation. This reduction in blood flow makes oxygen, energy and other nutrients less available to the epithelial layer of cells lining the intestinal tract. The tight junctions that hold the intestinal tract’s epithelial cells together weaken, allowing pathogens and toxins to more easily enter the bloodstream, leading to a condition called leaky gut.
How Heat Stress Impacts Immunity
Heat-stress induced leaky gut can take a large toll on an animal’s health and immunity. Once the bacteria, pathogens or their toxins pass between cells, the immune system recognizes them and triggers an immune response to destroy and remove the invaders. This inflammatory process requires significant amounts of already limited nutrients and pulls them away from other key functions like muscle growth and reproduction.
This chronic inflammation can also have a negative impact on hoof health by causing a reduction in hoof horn tissue production. This leads to the formation of lower-quality hoof horn tissue and can eventually lead to lameness. During these periods of heat stress, cattle will also spend more time standing to dissipate heat – increased standing time can add to hoof health concerns.
Combatting Heat Stress with Zinpro® Availa® Zn
While heat stress may be unavoidable, there is a way to take preventative action and prepare animals to better cope when warmer temperatures hit. Zinc plays a key role in maintaining epithelial integrity and strengthening tight junctions. Feeding Zinpro® Availa® Zn — the most bioavailable form of zinc available on the market – can make cattle more effective at reducing leaky gut on pasture and in the feedlot.
When evaluated in heat-stressed cattle, feeding Zinpro Availa Zn proved to be effective in reducing leaky gut. Animals supplemented with zinc sulfate had a reduction in feed intake of 22.8% compared to only a 14.9% reduction in feed intake for steers fed Zinpro Availa Zn. Additionally, animals receiving Zinpro had lower rectal temperatures, indicating less inflammation after sustaining a period of heat stress.
Feeding Zinpro Availa Zn also had a positive impact on gut morphology with greater intestinal villi height and decreased villi width occurring in heat stressed and non-heat stressed cattle. Stronger gut morphology is important to maintain tight junctions and reduce intestinal permeability that leads to leaky gut.
Heat Stress Management Strategies
In addition to providing a balanced ration with Zinpro® Performance Minerals®, careful observation and management of the environmental factors within your control can help cattle beat the heat. Management practices to implement include:
- Handling: Reduce the amount of handling, transport and processing needed during high temperatures. If cattle need to be handled, do so during the lowest temperature with low-stress handling techniques.
- Water: Provide clean and cool water as cattle will increase water intake during high temperatures.
- Shade: Provide cattle access to trees or open buildings.
- Ventilation: Use fans for cattle being housed in enclosed buildings.
Solutions to Reduce Heat Stress and Improve Performance
Heat stress is a widespread issue that cattle producers must manage, and it’s critical to have a plan in place prior to the onset of hot weather to prevent the long-term effects heat stress can cause. By incorporating performance trace minerals like Zinpro Availa Zn, cattle are better able to reduce the impact of leaky gut during heat stress conditions.
To learn how to bolster your beef cattle nutrition program, contact a Zinpro beef team member.
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