Cattle are generally doing fine in spite of the winter weather. Their rumens are keeping them warm, said Travis Mulliniks, beef cattle nutritionist with the University of Nebraska-Lincoln Extension, stationed in North Platte, Neb.
He said cattle and other ruminants can generate a lot of heat in the process of digesting their food. The rumen is a specialized stomach with four compartments.
Wind protection and attention to feed quality also help.
Dr. Rolland Kramer, veterinarian at Stockman’s Vet Clinic in North Platte, said periods of extreme cold and blowing snow can take a toll, but rows of trees, called shelter belts, can make a difference. Anything that blocks wind is important, he said.
That is especially true when calves are being born, although “we’re on the front edge of calving season” now, he said. The busiest calving time is March and April.
Mulliniks said cattle producers who calve in January and February typically have barns or other shelters to “get calves dry and sucking the dam,” feeding on the first milk from their mothers, right away. Later-born calves are not typically exposed to as much cold, but ranchers have to take special care for them when there are late-season snowstorms in March and April, he said.
When it comes to nutrition, it helps to have feed that is of lower quality so it stays in the rumen longer and generates more heat, Mulliniks said.
Besides cattle, ruminants also include sheep, deer and antelope. Their digestion relies heavily on bacteria and other microbes in their stomach compartments to ferment and break down plant fibers. They regurgitate partially fermented food, called the cud, chew it and swallow it again. The digestion process can take up to three days and can generate a lot of body heat.
To generate the most heat, ideally the feed will have 8 percent crude protein or less, and an energy value of 52 percent total digestible nutrients (TDN) or less. Those are numbers that are important to cattle producers, Mulliniks said.
Many producers graze their cattle on cornstalks over winter, and that works well. However, grain has a high TDN value and is digested too rapidly to generate much heat, he said. Heavy snowfalls can make it more difficult to graze. Then, feeding a low-quality hay can be a good alternative.
On the other hand, pregnant cows must have enough protein, especially during the last three months before birth, so the fetus will develop properly and the cow’s first milk will be of good quality and transfer immunities to the calf, Mulliniks said. Like humans, cattle have nine-month pregnancies.
Cattle grazing on cornstalks over winter do not normally need protein supplements, Mulliniks said, but “on winter range” in the Sandhills grass pastures, “we recommend 0.3 of pound of protein (supplement) per day” typically.
The key is providing for the animals’ needs.
“On each situation, how to achieve that is going to be different,” Mulliniks said.
Kramer said “the ranchers do a good job.” At the veterinary clinic, he said, “we’re not getting many calls.”