Cattle in pasture

Warm fall days combined with cool nights can present challenges to the immune system for cattle.

With weather conditions ranging from tropical to cool, the immune systems of cattle in the Midwest will be tested as fall approaches.

Dale Grotelueschen, a veterinarian and director of the University of Nebraska’s Great Plains Veterinary Educational Center in Clay Center, says weaning calves is one challenge many producers face this time of year.

“You have naive animals transitioning into a new environment,” he says. “Animals that are preconditioned are less likely to get sick when they are moved into a backgrounding operation or a feedlot.”

Grotelueschen suggests producers consult with their veterinarians on the proper time to vaccinate calves.

“Certain things become stressors, so management comes into play,” he says. “For example, wean calves roughly 45 days before they transition to a new environment. That is going to reduce the stress on them and make them less likely to get sick.”

Commingling is another cause for stress among cattle, Grotelueschen says.

Dome diseases, such as BVD (bovine viral diarrhea), can suppress immunity.

“A management program that optimizes the immune system is very important,” Grotelueschen says.

Nutrition also plays a role in immunity, says Grant Dewell, Extension beef veterinarian with Iowa State University.

He says rations that are low in energy can make calves more susceptible to illness.

“Any differences in what they are used to will likely affect their immune system,” Dewell says.

Producers must also pay attention to vitamin and mineral intake. Dewell says vitamins A and E are vital to ensure immune systems are functioning properly.

“Typically they are going to get those through grazing green grass,” he says. “You need to make sure they transition into something similar after weaning, such as high-quality hay.”

Dewell says minerals such as copper, zinc, manganese and cobalt are also important to the immune system.

“Calves may not pay much attention to the mineral block, so you need to monitor that,” he says.

Warm days and cool nights can impact the health of cattle in the feedlot, Dewell says. He says bedding should be kept fresh to help cattle get out of muddy conditions.

“Do what you can to keep them dry and in a well-ventilated area,” Dewell says. “Keep a close eye on calves when they first enter the feedlot. If they get sick, they can go south in a hurry.”

Grotelueschen says calves just entering the feedlot may have lost their colostral immunity, adding the immune system does not reach full maturity until puberty.

“It’s not just about average daily gain,” he says. “You need to make sure those calves stay healthy.”

Jeff DeYoung is livestock editor for Iowa Farmer Today, Missouri Farmer Today and Illinois Farmer Today.