Don’t turn hungry cattle out on cornstalks in drought-damaged fields or they could suffer from acute acidosis, says Ron Lemenager, Purdue University Extension animal scientist.

Acute acidosis is characterized by a sudden drop in rumen pH caused by rapid grain overload. It can lead to illness or death.

“In the more seriously stressed, lower-yielding fields, some producers are reporting ear drop resulting from stalk quality issues and ‘nubbin’ ears that are slipping through the stripper plates of the combine head,” says Lemenager. “Collectively, this ear drop can create acute acidosis when grazing cornstalks if not managed correctly.”

Part of that management: scouting fields before turning out cattle to determine how much corn is there.“Cows seem to have a homing device, and they will find ears wherever they are in the field,” he says.

If there is a lot of corn, producers can adapt their livestocks’ rumens to starch by daily feeding – for several days – several pounds of corn grain each before turning them out to graze.

Cattle also should be full of dry hay before turnout, so they don't eat as many ears of corn. And fodder should be grazed around midday, when it will be dry from morning dew. Dry forage stimulates saliva production and can provide a bit of a rumen buffer to help minimize a sudden pH drop, Lemenager adds.

He also suggests limiting grazing to smaller field sections.“Consider strip grazing using a single hot wire to include only a portion of the acreage and make sure it includes a drinking water resource. This will prevent cows from gleaning the entire field of ears and will force them to consume leaves and shucks to dilute the intake of grain.After several days, rumens should be adapted to starch and the concern of acidosis is reduced.”

Cattle with acute acidosis symptoms will at first look stressed or gaunt and could stop eating. Then they could have loose, gray stools and eventually might have elongated hoof growth.

“If cows are showing signs of stress, the best bet is to get them off of stalks and onto dry hay,” he says. “But the key here is to prevent acute acidosis rather than try to treat it.”