By Jaclyn De Candio
Today’s commercial beef cattle tend to be quite robust thanks to genetics and careful selection for health traits. But there is one inevitable Achilles’ heel that can wreak havoc on the healthiest of animals—transitional stress.
Hauling up the road, weaning calves, or bringing back a trailer load of new purchases from the sale barn are stressful events contributing to immunosuppression. While it is impossible to eliminate all stressful events, there are ways they can be managed to reduce impact on animal health.
Stress is inevitable in cattle production, but it’s the ability to reduce the intensity and duration that makes the difference for animal health. Proper management practices can significantly lessen how much stress animals experience, particularly during key transition periods.
Cattle owners and stockers can face challenges when it comes to moving cattle from “stage to stage,” such as transition stress syndrome, which can compound existing problems.
What Causes Stress?
Before we look into remedies, we should clearly define what stress is in livestock.
“It’s the inability of an animal to cope with stress that affects its ability to maintain a homeostatic state,” explains Dr. Karen Schwartzkopf-Genswein, principal research scientist of Beef Cattle Physiology and Welfare at Agriculture and Agri-Food Canada. “These changes in the environment can range from minor to major, and there’s a gradient in how well they can adapt.”
Stress is a multifaceted issue caused by a variety of factors. It can happen during transitional phases in a cow’s life cycle, such as changes in the animal’s environment, handling, social dynamics, or nutrition. Schwartzkopf-Genswein notes that stress is an adaptive response, but chronic or overwhelming stress can impair an animal’s ability to cope.
“One common stress response is secretion of glucocorticoids (cortisol),” she says. “Cortisol can increase morbidity and mortality in cattle by reducing immune function. The greater amount of cortisol and the longer the period of time it’s elevated in the blood, the greater effect it has on reducing immune function.”
The suppression of immune function due to prolonged cortisol elevation makes cattle more vulnerable to infections, particularly during stressful transition periods. This is especially evident in calves moving through the production system.
“Calves are transitioning from one sector of the industry to another, usually from the cow-calf to the feedlot sector,” explains Dr. John Campbell, a veterinarian at the University of Saskatchewan. “During that time period, there’s a lot of different stressors that hit those calves and as a result, they end up being exposed to the more common diseases, such as bovine respiratory disease (BRD).”
Stress isn’t just a concern for cow-calf operations or the feedlot sector—it affects everyone who handles the cattle. According to Campbell, stressors like commingling—when animals are brought together during sales or transport—are major contributors. Not only are animals exposed to unfamiliar peers, but they’re also encountering new viruses and bacteria.
“Probably the number one stress is weaning,” Campbell notes. “If calves are weaned, sold, and then transported immediately, stacking those stressors significantly increases the risk of illness.”
Nutrition and Health
Many of the most critical diseases in feedlot cattle are associated with movement to the sale barn and difficulties adapting to a new diet. These include the all-important BRD and other metabolic diseases.
“We know preconditioning is very helpful in terms of reducing the incidence of BRD because its goal is to reduce the number of stressors calves are exposed to within a short period of time,” says Schwartzkopf-Genswein. “Then they’re happening one at a time, instead of all together and all right before an animal transitions, which is an additional stressor.”
In addition to preconditioning, ensuring proper nutrition at all times is a must. Maintaining rumen health is essential because both overly acidic or basic conditions in the rumen can disrupt the microbe population, leading to poor digestion and nutrient absorption.
A properly balanced diet not only supports digestion but is critical for immune integrity, particularly when animals face stress. Stress can exacerbate an already weakened immune system, further compromising an animal’s ability to fight off disease.
Minerals and vitamins play a crucial role in regulating immune function and producing key proteins needed for health. Campbell highlights the importance of trace minerals, such as copper, in maintaining immune strength.
“Many cattle in Western Canada are copper deficient, and I’m sure that’s true in other parts of the country as well,” Campbell explains. “Copper plays an important role in the immune system, and research on other trace minerals shows they are essential for proper immune function.”
Campbell also emphasizes that addressing mineral deficiencies can be challenging, particularly in a multi-sector system where the costs of maintaining animal health at the cow-calf level may not always be reflected in higher returns.
While feed and water intake are critical for growth, cattle often decrease consumption due to stressors in the transition period. Usually, cattle will show erratic eating and social behaviors the first week at the feedlot.
Disease Prevention
According to Schwartzkopf-Genswein, it can take about a week to 10 days after arrival for animals to go back to normal. Of course, this can vary from animal to animal.
“The stress hormones typically come back to normal fairly quickly,” she says, “but some of the behavioral indicators or behavioral responses take a little bit longer. Feed intake is a big one.”
Nutrition and animal health are key not only to overall herd health but also to navigating any transition periods. Supplying proper nutrition and having a well-conceived vaccination program can help keep immune systems strong so cattle can ward off disease.
It can take anywhere from three to four weeks for an animal to adjust to a significant transition like entering a feedlot or arriving at a new farm. Some factors impacting the severity of stress include new management, new herd mates, new environment, new diet, and handling.
Weaning and commingling are two of the most critical stress points. While the multi-sector system can’t be completely changed, there are steps producers can take to minimize stress, notes Campbell. One of the most effective measures is to keep weaning and shipping as two separate events.
“Instead of weaning and shipping calves on the same day, weaning them ahead of time allows that stressor to pass before they’re transported,” he says. “You can also adapt them to eating at a feed bunk beforehand to ease the transition.”
Additionally, Campbell recommends stress-free weaning strategies and similar management practices to reduce the likelihood of respiratory issues. Vaccinating calves before transport is also key. And of course, a good preconditioning program with proper vaccination helps boost immunity and provides protection before they encounter new stressors in the feedlot environment.
Effectively managing stress goes far beyond improving animal welfare. It’s also crucial for enhancing overall herd health and productivity. By implementing strategies such as gradual transitions, proper nutrition, and careful handling, producers can significantly mitigate the negative effects of stress.
“I really think the focus has to be on management because, obviously, our goal is to reduce the use of antimicrobials,” emphasizes Schwartzkopf-Genswein, “so we don’t build antimicrobial resistance in our animals.”
Prioritizing these management practices will help maintain not only a more resilient herd but also a healthier, stronger beef industry.