Cattle health is influenced by many factors including nutrition, environment, stress, exposure to pathogens, etc. Going into winter, cattle should be in good body condition and have adequate forage.
Megan Van Emon, Ph.D. Extension Beef Cattle Specialist, Montana State University, says health depends on proper nutrition for a strong immune system. Cattle also need enough forage to generate adequate body heat and not have to rob fat to keep warm. A thin cow has less insulation against cold and needs more food. Thin cattle are more vulnerable to cold stress and may have weaker immune system.
“Pregnant cows need more feed. In some regions it’s the challenge to provide adequate nutrition because of drought the previous summer,” she says. In this situation many cows go into winter in thin body condition. Some ranchers run short on hay early in the winter because they had to start feeding too soon.
During cold weather, steps should be taken to minimize cold stress and wind chill. “Adaptation of cattle to winter temperatures (making transition during the fall) can help, but some years we’ve gone from 50 degrees to a sudden drop--below zero—within a week. This is hard on cattle, and tough to meet their nutritional requirements. Those requirements increase dramatically when temperature drops below 32 degrees. If cattle have time to adapt gradually, developing a good hair coat, their critical temperature is lower,” she explains.
“Natural windbreaks like trees, or a hill that stops the wind, can help. If they have a place to avoid most of the snow and wind, cattle do better and maintain body condition and stay warmer. When they have to use body fat to generate heat and maintain themselves and fetal growth, this can be detrimental. If it’s 20 above zero and next week it’s supposed to be 40 below, increase the amount you feed, and be ahead of the curve. Cattle use rumen fermentation digestion (which creates heat) to maintain body heat, so bulky feeds like hay will stay in the rumen longer and help them stay warm,” she says.
“Grain or silage are digested too quickly to have much effect on keeping cattle warm in cold weather. They need more forage, and if you are feeding hay, timing can make a difference. You might feed twice a day, with most of the ration in the afternoon or evening so they can use it through the night to keep warm,” says Van Emon.
“We see a lot of illness in calves some years because they don’t have a strong immune system, due to the cows’ inadequate nutrition during gestation.” Also the cows may not have produced optimum colostrum, so the calves were not as protected with maternal antibodies.
If you are wintering weanlings/yearlings, keep them in a clean environment and monitor closely for disease. “Weaning is probably the most stressful time in an animal’s life. They need pre-weaning vaccines, and a clean environment after weaning.” Often the healthiest place for this age group is on pasture rather than confinement; this will reduce stress.
Make sure cattle have adequate water. “Cattle won’t eat enough if they don’t have enough water. Also, some water sources are high in sulfate or nitrates. Check your water as well as your feed, and send samples for testing,” she says.
Cattle will eat snow if they don’t have water—if snow is not crusted, and if there is adequate moisture in it. If they are grazing winter pastures and licking snow as they graze (taking a bite of grass and a lick of snow), they may do fine, but if they are eating hay (a big meal all at once) they need more water.
“Provide a good mineral mix and vitamins, with lick tubs or loose mineral. This may be the most expensive part of the diet but well worth it because it plays an important role in cattle health—and the cow is transferring those minerals to her fetus. This helps the immune system and helps create a stronger calf,” she explains.