Summertime brings in the warmer weather and, with it, a different set of stressors for cattle. A number of factors can lead to stress in cattle, including fluctuations in temperature or adverse weather conditions. Although some factors are out of our control, there are steps producers can take to minimize stress and keep animals healthy.
Signs of stress
Stress comes from a variety of places. There are stresses that can be limited by management practices, but when it comes to environmental stressors, there may not be much you can do.
“Stress can come from excessive heat, natural disasters, snowstorms, hurricanes or anything that is going to create an immediate and abrupt change in the environment,” says Lee Jones, DVM, Boehringer Ingelheim. “Cattle have the ability to adapt, but anything that's a really abrupt change causes stress, and the more severe the change, the more severe the impact of stress.”
Cattle need time to cool down after experiencing hot temperatures, says Eric Moore, DVM, Norbrook. This usually happens at night from 3 p.m. to 3 a.m. However, when it stays above 78ºF, it doesn’t let that heat dissipate in the cooling time. This is what creates heat stress and exhaustion.
“Stress has a physiological impact,” Jones says. “We begin to see signs most of the time when we see cattle don't have appetites or start to become sick. Cattle may lie around more often and don’t have normal grazing behavior. Anytime that you see a significant behavior change, try to find the cause.”
Overall health keeps cattle profitable, and a big component of that is limiting stress. Cattle may show they are stressed in different ways.
“Just watch their behavior,” Jones says. “Cattle show they are stressed with anything out of their abnormal behavior, so it's important to know what normal, comfortable behavior looks like. Cattle that are stressed are going to be more alert and reactive.”
Stress raises cortisone levels, and the effect on the animal’s white blood cells can last for five to seven days after the stressful event, Moore says.
“Like people, cattle can get severe heat stress and even heat exhaustion, and it changes their physiology,” Jones says. “Some of the physiological effects we see include white blood cells that don't function as well as possible. The way cattle release heat is through breathing, so if they're breathing in air as hot as they are, then they're not going to be able to expel that heat. With increased body temperatures, the immune system is suppressed, and the animals are more susceptible to pathogens. We've seen some things in the environment that really would not affect a normal healthy calf but do when animals are severely stressed.”
He continues by adding that water quality is impacted by the heat as water is going to evaporate, leaving poor-quality water behind. Because the animals are thirsty, they will drink the poor-quality water, which can affect their gut function.
Depending on the severity of the impact of heat stress, the animal may have lasting impacts and be at a high risk of dealing with heat stress again in the future.
Ways to minimize stress
“Sometimes we can get too focused on the sick animal,” says Ron Tessman, DVM, Elanco. “We need to step back and not focus so much on the sickness but focus on wellness and what we can do to mitigate so that animal doesn't get sick.”
Healthy and properly cared for cattle handle stress better compared to those who are not, Moore says. Cattle should be in good fleshing (proper body condition). They should have appropriate mineral supplements, access to quality water and have shade to cool off after grazing. All these things will help cattle handle stressors, especially the heat, better.
Animals stressed out in the heat can have health issues like scours and pneumonia, Jones says. Shade can be a great solution whether it be natural, like access to trees, or simple shade cloths or other products.
“When it comes to minimizing stress in the summer, the most important thing is shade and water,” Jones says. “If you don’t have natural shade, you might be able to build some shade, and you'll find that the cattle will move to that area. If you're lucky enough to have some natural shade, the cattle will congregate in those areas and get underneath some trees. Cattle also need to stay hydrated. The best environment when it’s hot is a shaded area with central water.”
You should be doing things to alleviate any more stress during times of heat, Moore says. Creating practices like moving or shipping cattle early in the morning and having fly control creates the least negative impact on the animals.
When cattle are in shade, it’s equally as important to make sure there is adequate ventilation, Moore says. Without it, flies will become a big issue.
“Something as simple as a good fly control program can help address heat stress,” Moore says. “If cattle are bunched up and swatting flies, airflow is limited and cattle are creating more heat with every movement of their tail.”
Moore adds, “Are your cattle appropriate for your environment?”
Having appropriate breeds, hide colors and length of hair is the best way you can limit stress, especially heat stress.
“One of the things we do see is that black cattle seem to suffer the most,” Jones says. “They absorb a lot of heat from the sun, and their body temperature can be as much as 4 to 5 degrees higher than an animal that's red or white-hided and reflect rather than absorb the heat.”
Effects of shade
Proper shade can help cattle deal with heat and prevent heat exhaustion. A recent study by Kansas State University looked at what shade can do for a stocker operation and how it can be used to improve animal comfort. The study found calves in shaded pens panted less compared to those in non-shaded pens. Water usage was lower for calves provided with shade when compared with calves in non-shaded pens. Average daily gains (ADG) were greater for shaded calves compared with non-shaded calves, and final bodyweights were greater for calves in shaded pens compared with calves in non-shaded pens.
“We wanted to take a broader look at heat stress and measure the impacts of shade, as well as changing nutritional management, on heat stress, performance and water usage,” says A.J. Tarpoff, Kansas State University associate professor.
“The idea is that limit-feeding a highly digestible feedstuff compared to a high-roughage diet creates less heat from fermentation during the digestion process. What we found was that both changing nutritional management and shade usage can be helpful in reducing the impacts of heat during the summer months. Both strategies reduced panting scores, improved efficiency and increased daily gains. Interestingly, both strategies reduced overall water usage by just over a gallon per head per day.
“There is economic value in reducing stress in your cattle and developing wellness practices," Tessman says. Healthier, less-stressed cattle will be more efficient, more consistent in the feedlot and better able to utilize vaccinations and nutrients.
“There are a lot of products, but it isn't always about the products,” Tessman says. “It is about raising cattle with a wellness mindset and then using the products when we need them.”
