Beef cattle seeking shelter from harsh winter weather could be at an increased risk of disease in overcrowded barns, Purdue University experts say.
Extreme cold or rapidly changing weather can lower animals' immune response, leaving them more susceptible to disease, said W. Mark Hilton, clinical professor of beef production medicine.
"During good weather, beef cattle tend to spread out a bit and don't seek shelter," he said. "When the weather is inclement, and if a good barn is available, animals will seek shelter there. If the shelter is too small for the entire herd, or if it has poor ventilation, the viruses some animals harbor can be more easily spread to other animals."
Hilton recommends limiting access to barns and other shelters.
"If producers are calving in this weather, which I think is a mistake because the conditions are so variable, calves should have access to shelter while their dams should not," he said. "If cows and calves are allowed free access to buildings it becomes an almost impossible task to keep the environment clean."
Hilton said producers should make sure their animals have proper nutrition, suitable housing and all necessary vaccinations.
Ron Lemenager, Purdue Extension beef specialist, said cattle should be kept in outdoor lots and pastures unless the weather becomes unbearably frigid.
"Cows, replacement heifers and feedlot cattle can handle low temperatures pretty well when they have a dry, winter hair coat and protection from the wind," Lemenager said. "Where we run into problems is when we have low temperatures and wind chill factors."
Abrupt changes in weather, such as a quick warm-up with rapidly melting snow, can also pose problems since wet, muddy fields make it harder for cattle to move easily or find nutritious feed.
"Mud is always a challenge because it not only increases the energy required to maintain the animals but also because their intake is typically reduced," Lemenager said.
The problem of finding adequate nutrition is especially acute this year because last year's forage crop was hampered by extreme weather. After record rainfall and flooding early in the growing season, many forages were harvested too mature or with too high of a moisture content. As a result, forage quality was compromised.
"I have seen a lot of low-quality hay across the state that will not meet energy and sometimes protein requirements for cows in late gestation or early lactation," Lemenager said. "Adding a wind chill factor really puts those cows in jeopardy."
For every 10-degree Fahrenheit drop in the wind chill factor below 30 degrees, the energy requirements for a typical cow increase by 13 percent, he said.
"The bottom line is to get your forages tested so you know what nutrients are being provided and then work with a nutritionist to develop a supplementation strategy that will meet animal performance requirements."
It is also a good idea to provide cattle with warm, dry bedding, Lemenager said. Bulls especially need bedding to prevent scrotum frostbite, which can result from the animals lying on frozen ground or concrete.