The pros and cons of winter calving

Published 9:32 am Thursday, December 26, 2019

Still an old cowman at heart, to me there’s nothing prettier this time of year than a herd of cows with their newborn calves by their sides.

Baby calves in December used to be rather uncommon, most calves being born in the spring months 30 years ago.

A few folks had a fall calving season beginning in October. But that was more common to the north of here where fescue grass pastures provided green grazing during the cold months when our subtropical bermudagrass and bahia pastures were and still are brown and void of eats.

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So the old standard locally was to have bulls in with the cows April through July. Calves would come from February to mid-May the next year with most hitting the ground in March and April, the length of gestation, i.e. pregnancy, for cattle being 284 days.

That historic spring calving period this far south coincided with the best quality grazing period. And that meant cows were at peak milk production right on through early summer.

The slow shift to planned winter calving periods was for two main reasons. First, the older the calf, the more milk it can consume and convert to bodyweight to sell. Those little April born fellows, cute as they were, just couldn’t use all the milk their mommas could generate in spring.

Nowadays, four month-olds born back in December can max out spring milk plus they are soon old enough to graze and digest grass right along with their mothers. As pastures begin to lose some luster in dry, hot summer, calves born in winter have reached weaning age and are ready to sell. This gives their mothers a head start in recovering from about seven months of nursing while also gestating next year’s calf for three or four months.

Another reason for having calves born in winter has to do with traditional price trends. Most calves are weaned from their mothers and sold at about seven months of age. There are no guarantees and there have been exceptions, but in most years calf prices in July and August are higher than in October and November. Advantage: winter calves.

Of course, there are challenges that come with controlling the birth time of calves to be in winter. Genetics and herd health programs are major effects on cattle fertility and growth.

The biggest winter challenge is nutrition for the cows. With natural grazing on most farms unavailable for four colder months, everything must be hauled in and put before the cows to eat. Hay accounts for most of it, but hay does not furnish enough protein and vitamins, both of which must be supplemented.

While managed winter nutrition of grown cows has a definite and near-term effect on the growth of their newborn calves, it has an even bigger effect on next year’s calves. That’s because a cow will not conceive and deliver a calf next year if she gets significantly shortchanged this year.


Terry Rector writes for the Warren County Soil and Water Conservation District.