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Mineral Supplements in Pregnancy May Program Calves for Better Gains

Fetal programming – the idea that lifelong performance is preprogrammed before calves are born – is sparking new thinking among beef researchers. Mineral supplementation of cows during pregnancy is one example.

Reinaldo Cooke, a beef specialist at Oregon State University, did a recent study on the topic. The issue actually started in humans, he says, where it’s well known that babies thrive better when their moms are in a positive nutritional state during pregnancy.

Even though human diets tend to be diverse with lots of trace minerals, doctors still often recommend that pregnant women take extra supplements, just to be on the safe side. 

Cows, on the other hand, may spend most of their pregnancy without nutritional supplements. “In Western areas like ours, cows go out to range pastures in the summer without supplements,” says Cooke. “Deer, elk, or other wild animals would eat most of it anyway.”

Bred on the range, cows usually spend the first two trimesters of pregnancy there. “They come back to the ranch about November, and then we can supplement them,” he says.

testing a fetal programming idea

Cooke wondered if it would help the calves if the cows were given generous supplements of zinc, manganese, copper, and cobalt in the final trimester of pregnancy. So, he did a test.

“We split a cowherd into three groups. The control group got no supplement. A second group got inorganic mineral supplements. A third group got organic supplements, which cost a little more but are considered to be better absorbed,” he says.

Cooke says it’s important to note that none of the cows in any of the groups was deficient in minerals to start with. “They were all in good shape,” he says. “Our experiment was not about correcting a deficiency; it was about pushing extra nutrients to see if we could program the calves for better performance.”

Weaning weights averaged 25 pounds higher for calves from the cows on the inorganic mineral supplements and 54 pounds higher with organic versions. 

“Just putting simple math to it, we gained up to $70 in calf value with an investment of $2 or $3 per cow,” he says.

They followed the calves all the way through finishing. “We had less symptoms of respiratory disease with calves from the cows that got organic supplements. Carcass weight at harvest averaged 40 pounds more among those calves.

“There’s something going on here,” he says. “We still have some questions. Was it really fetal programming? Or do cows simply need more trace minerals than we previously thought?”

One thing he does know is that cows need to be kept in good body condition to start with. “Accomplish that first,” he says. “Once you have that in place, you can start thinking about enhanced mineral supplementation during pregnancy. Perhaps then you’ll get a benefit.”

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