As temperatures and humidity levels reach above 80 degrees Fahrenheit, beef cows experience physiological stress trying to deal with their heat load.
This manifests in two ways for cattle – physically and internally. Most beef producers experience the visible or physical signs of heat stress like panting, drooling, reduced feed intake and decreased activity in the summer. Still, the internal signs cattle undergo can be much more devastating.
Most contribute performance losses from heat stress to reduced feed intake, but that’s only part of the story.
Understanding Heat Stress in Cattle
“Heat stress equals gut stress,” says Dr. Jeff Hill, ruminant nutritionist for Ralco. “A ruminant’s primary mechanism for heat loss is panting and pushing blood to the surface of their bodies. This natural mechanism, called vasodilatation, robs nutrients and blood flow from their internal organs, affecting reproduction, metabolism and gut health.”
As you can see from this graphic, stress compounds in an animal and contributes to additive losses. For example, heat stress can predispose an animal to a leaky gut, which triggers an immune response and makes an animal even more susceptible to disease and production losses. Which further reduces their ability to tolerate heat. This process continues in a vicious cycle.
What’s Leaky Gut?
Leaky gut describes when the intestinal wall of an animal becomes damaged and porous, allowing toxins, microbes, undigested food and waste to leak through. This can result in performance losses, sepsis and even death.
The micrograph on the right shows what a damaged or leaky gut is compared to a healthy gut. The gaps in the right image would allow pathogens and toxins to pass through, increasing the risk of disease challenges during heat stress.
Heat stress means gut stress when it causes a leaky gut. A leaky gut then triggers immune activation from bacteria and pathogens passing through. Energy such as glucose then begins shifting away from milk production and insulin levels increase. This results in performance losses from poor nutrient conversion, poor reproduction and disease.
Below is an in-depth look at new technologies to combat heat stress in ruminants in a webinar by Dr. Jeff Hill.
Best Ways to Manage Heat Stress in Cattle
New research shows that feed additives, including essential oils and capsicum, are helping beef producers keep cattle cooler in the summer months. In a West Texas A&M University study, Wagyu cattle had a higher average daily gain, feed intake and better marbling scores at the market when fed essential oil and capsicum feed additives throughout the summer months.
Why? Essential oils and capsicum products target the internal processes in the body that are impacted by heat stress.
Essential oils contain powerful properties that help reduce oxidative stress, maintain tight junctions in the gut to combat leaky gut and trigger responses in the body that help modulate temperature and regulate insulin and glucose production.
Additionally, capsicum helps regulate insulin, glucose production and temperature, allowing animals to take smaller, more frequent meals. This helps maintain gain and rumen function during heat events.