Farm Progress

Reduce the impact of heat on cattle with genetic selection.

July 18, 2017

2 Min Read
INTRODUCE NEW GENETICS: Want to keep your cattle cool in the hot summer? Consider cattle with heat-tolerant genetics and good shedding scores.SPmemory/iStock/Thinkstock

Missouri's hot weather this month is making life out of doors uncomfortable for farmers and a few cows.

With temperature in the upper 90s and heat indexes above 100 degrees F, the scenario is set for heat stress in beef herds.

Cattle producers are taking a number of steps to reduce the impact on cows and calves by providing adequate water and shade. But one University of Missouri Extension livestock specialist says cattle producers may want to change their cattle genetics to keep heat stress at bay in their herds.

Selecting heat-tolerant cattle that that match their environment means they'll be more productive, less stressed and more effective at using the resources available to them, says Erin Larimore, a University of Missouri Extension livestock specialist from Jackson.

"Bottom line — matching cattle genetics to the production environment is profitable," she says. "In Missouri, we need to select cattle that are heat-tolerant and are able to graze toxic fescue without suffering production losses."

She shares a short list of methods available to breed cattle adapted to hot temperatures with high humidity levels. They include:

• Introduce Bos indicus breeds into the herd.
• Select cattle that shed their winter coat in early spring or summer.

The ability to shed the winter coat early is an effective predictor of a cow’s ability to cope with heat stress, she says. Larimore points out that calves from cows that shed their winter coat weigh more at weaning. Cattle with enhanced ability to shed hair can potentially tolerate fescue toxicosis better.

A hair shedding score is easy to evaluate. "You may be able to identify genetic lines of cattle that have an increased ability to shed hair, since there is a moderate heritability of hair shedding," she says.

Shedding scores should be taken in spring or early summer and are on a scale from 1 to 5. A score of 5 indicates an animal that still has its complete winter coat, with no evidence of shedding. A score of 1 is a completely slicked-off animal.

Producers in hot, humid environments should consider a hair shedding score as one part of their selection criteria. "Earlier-shedding cattle are better suited for these environments, and will be more productive and profitable," Larimore says.

Source: University of Missouri Extension

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