Winter management must start in the fall, before cold weather. This means carefully assessing body condition on pregnant cows when calves are weaned, and developing a plan to provide sufficient nutrition to allow cows to maintain moderate-to-good condition before their next calving.

James England, University of Idaho DVM, says cows must be in good condition (preferably a body condition score 6) to handle weather, calving and rebreeding. “With adequate condition at the start of winter and good maintenance throughout, most animals winter well. But, without adequate nutrition, anything else we do is set up for failure,” he says.

Stockmen often underestimate the importance of fall nutrition and body-condition scoring. In fact, Ron Skinner, a Hall, MT, DVM and seedstock producer, says about 70% of open cows in Montana each year are the result of inadequate fall nutrition.

An adequate, balanced diet may merely mean adding a trace-mineral supplement to native pasture, some good hay, a protein supplement if grass becomes too dry, or hay if the grass becomes depleted or snowed under. If a cow is deficient in protein or phosphorus through fall and winter, she won’t rebreed on time after calving. Plus, thin cows are unable to handle the stress of bad weather and lose more weight. And, it takes more feed to put weight back on a cow during cold weather.

If you manage pastures properly – without overgrazing or running out of grass – forage-efficient cows won’t lose much weight during fall or winter grazing; they generally gain weight after weaning calves and go into winter with fat reserves.

Many factors influence a winter-feeding program. These include climate and grass growth; whether pastures snow under and can’t be grazed; the available forage your climate or operational design (irrigated vs. nonirrigated pastures, forage varieties, crop aftermath, etc.) allows; and the type of cattle. It’s most profitable to match the cattle to your feed sources rather than try to feed cattle not fit to the environment.

To help cattle maintain health and body condition during winter, vaccinations should be up to date, parasite populations assessed, and cattle dewormed and deloused, if necessary.

“If lice are a winter problem, it’s best to delouse cattle in late fall/early winter, before lice start to increase in numbers,” says Jack Campbell, University of Nebraska professor emeritus. “Lice increase their reproductive rate in cold weather, so you get more generations in a shorter time span.” A good kill in early winter – before lice affect cattle performance – will generally keep cattle free of these parasites until spring.