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Oct. 10, 2023 |  By: Mark Moran - Public News Service

Experts warn of dangerous high-nitrate cattle feed

cows

By Mark Moran - Public News Service

Livestock experts are warning farmers about high nitrate content in their cattle feed this fall because of Iowa's prolonged drought.

Farmers typically grind up corn plants - stalks, ears, stems and all - to feed their cattle. It's called silage, and it's a healthy source of protein and other nutrients for the cows.

But extended, severe drought in Iowa has disrupted the biological process that normally converts nitrates into protein in the silage.

Beth Doran, a beef specialist with Iowa State University, said nitrates can be dangerous for the cattle.

"Nearest way to describe this for a consumer is to think of it kind of as carbon monoxide poisoning," said Doran. "The nitrates tie up the ability of the blood to carry oxygen to the animal. And so, that can cause problems. It can cause death if it gets too severe."

Doran said typically, moisture would carry the nitrate into the stalk and convert it to protein - which has not happened because of below-average rainfall.

Doran said letting the silage sit for a month or so will allow some of that nitrate to protein conversion to happen organically, a process called fermentation.

But Doran still recommended having the silage tested by a commercial lab before feeding it to cattle, especially young cows.

Doran said letting the silage ferment can reduce the nitrate content by as much as 60%, which then allows farmers to blend it with other low-nitrate feed.

Even though the summer heat has subsided and there has been some rainfall across the state, the moisture can cause almost as much harm as severely dry weather because - Doran said - the corn plant is getting mixed signals from Mother Nature.

"You know, in other words, we start out dry then we got some little rains, then it went back into dry and then we got into rains," said Doran. "That increases the amount of nitrate that can be in that stalk."

Doran said nitrate tolerance ranges with the type and size of cow. Feedlot cattle of more than 700 pounds tend to be more tolerant, and younger animals are less so.