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Beware vitamin and mineral deficiencies in the cow herd during drought

News Roundup from the September 27, 2021 issue of Canadian Cattlemen

Dry pastures can mean vitamin A deficiencies in both cows and calves this fall.

As ranchers pull cattle from parched pastures this fall, veterinarians and livestock nutritionists advise watching for vitamin and mineral deficiencies

“This year we’re going to be seeing a lot of guys feeding some alternative feeds, maybe a little bit more straw in their rations, so it’ll be important to balance off those important macro minerals and trace minerals and vitamins for those cows to make sure they get through the winter without any hiccups,” says Courtney O’Keefe, ruminant nutritionist with Blue Rock Animal Nutrition at Innisfail, Alta. 

It’s not just the feed that can create mineral deficiencies. O’Keefe suggests testing water, focusing on the sulphates, nitrates and total dissolved solids, and to look at this alongside your feed test. 

“In a dry year we can see that those minerals and nutrients can become more concentrated in the water as that water table drops or evaporation occurs, and sometimes you can see cumulative effects between the feed and the water, which can lead to other problems down the road,” she says. 

Dr. John Campbell, beef cattle researcher with the Western College of Veterinary Medicine, recently presented information on vitamin and mineral considerations during drought at Ag in Motion’s Livestock Days at Langham, Sask. During an interview on-site, Campbell noted that copper deficiency is the most commonly seen trace mineral deficiency across Western Canada. Nearly 50 per cent of cows are close to deficient in some studies they’ve done. 

“And the interesting thing about drought years — especially in those areas where high sulphate water and sulphate feeds occur — we see that sulphates bind copper. So it can make a problem that’s already significant even worse.” 

Producers can ask their vets to take blood samples from cows to check for copper deficiencies, Campbell adds. It’s best to address copper deficiencies in the fall and winter, he says. 

“It’s when we have more control over our trace mineral program and we want to make sure those cows are in good cop- per levels prior to breeding next year.” 

How to supplement cows is another question. Campbell says force-feeding minerals is a better approach than free-choice, but he acknowledges the logistics don’t always make it possible in extended grazing systems. But if producers are dry-lotting more cows this year or feeding different things, it may be more realistic. 

For those feeding free-choice minerals, Campbell suggests combining salt with trace minerals, as salt helps drive intake. “Monitor the intakes as well and make sure your cows are eating trace mineral.” 

Vitamin A deficiencies on dry pastures 

Another issue to watch for is vitamin A deficiency. 

“Vitamin A is all derived from beta carotene, which is part of the green plant. Around Saskatoon at least we’ve had almost no rain since June, and we know that there’s not much green stuff left out there. And to top it off, we know cows are going to be on stored feeds longer this year than other years, so they’re highly likely to be quite deficient in vitamin A,” Campbell says. 

Vitamin A is crucial for immune function, reproduction and eyesight, among other things, says Campbell. A newborn calf relies on the cow for vitamin A, and calves born with this deficiency are three times more likely to die than calves with adequate vitamin A. Campbell says it’s important to make sure both cows and calves coming off dry pastures are properly supplemented. Consider injecting it to improve their levels right away, then make sure it’s supplemented in their ration or trace mineral mix. 

Calves born with vitamin A deficiencies are three times more likely to die than calves with adequate vitamin A, making it an important trace vitamin. 

“We’ve got so many challenges with drought this year, this is just one other to add on top of it,” says Campbell. But making sure cows have adequate vitamins and trace minerals is “important this fall and winter.” 

O’Keefe suggests contacting nutritionists and veterinarians for suggestions on managing the herd’s nutrition and feed requirements as we head into winter. 

“Reach out if you have questions, and definitely in years like this, especially to help you make the best decisions that you can with the resources that you have.”


For more content related to drought management visit The Dry Times, where you can find a collection of stories from our family of publications as well as links to external resources to support your decisions through these difficult times.

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Lisa Guenther is the editor of Canadian Cattlemen. You can follow her on Twitter @LtoG.

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