UNL experts discuss health concerns of cattle on cornstalks

This time of year, many ranchers are turning their cattle out on cornstalks to graze. Although commonpractice in several states across the U.S., it is important for producers to recognize concerns associated with letting cattle out on cornstalks, as it could create health problems in the herd. 

During an episode of the University of Nebraska-Lincoln’s (UNL) BeefWatch podcast, dated Oct. 2, UNL Extension Beef Educator Dr. Lindsay Waechter-Mead discusses a corresponding article titled “Understanding Health Concerns of Cattle on Cornstalks,” published in the October UNL BeefWatch Newsletter.

Waechter-Mead states an easy and efficient way to prevent health issues in cattle on cornstalks is to test corn in the field. 

Acidosis 

According to Waechter-Mead, the first health concern when grazing cornstalks is acidosis, which occurs when cattle consume a large amount of feed containing high quantities of fermentable carbohydrates – sugars that are easily digestible. 

This happens when the field contains too much dropped corn, which overloads cattlesʼ stomachs with grain, ultimately changing how they digest corn. 

This can lead to many health concerns including an increase in lactate formation, which damages the rumen by decreasing its pH, therefore affecting the animalʼs blood volume and tissue hydration status. All of this leads to acute clinical signs of diarrhea, dehydration, depression and anorexia, with long-term effects of abortion and laminitis.  

Waechter-Mead notes treatment may include restoring rumen microbes, correcting dehydration and the acidic rumen microenvironment and managing secondary complications.

“Management is key to preventing acidosis and is more rewarding than treatment,” writes  Waechter-Mead. “Knowing how much corn is in the field will help establish a grazing plan. The risk of acidosis increases if fields contain more than eight bushels of corn per acre.”  

She further explains bushels can be estimated by counting dropped ears of corn in three separate 100-feet rows and then dividing the number by two.

If too much dropped corn is a concern, Waechter-Mead encourages producers to acclimate cattle beforehand by slowly increasing their corn intake over 10 days. 

Nitrate toxicity 

The next biggest health concern for cattle on cornstalks is nitrate toxicity. This occurs when cattle eat plants with high nitrates, usually due to stress such as experiencing drought. 

“When a ruminant consumes high-nitrate plants, the rumen microbes convert nitrate to nitrite. Excess nitrite is absorbed into the bloodstream, where it changes the oxygen carrying capacity in red blood cells by converting hemoglobin to methemoglobin,” Waechter-Mead explains. 

She notes since methemoglobin isn’t able to carry oxygen to body tissues, the end result is asphyxiation. 

Nitrate toxicity can also cause weakness, rapid breathing, lethargy, muscle tremors, abortions and sudden death.

To prevent nitrate toxicity, Waechter-Mead encourages producers to take nitrate samples of standing plants or baled forage so they know the nitrate levels of the cornstalks they intend to feed to their cattle. 

She explains forages with more than 10,000 parts per million (ppm) nitrate may lead to toxicity and sudden death, while forages with over 5,000 ppm should not be fed to pregnant animals due to the increased risk of abortion and stillbirth.

“Any health concerns should be discussed with a local veterinarian to establish proper prevention and treatment protocols,” she concludes. 

Preslee Fitzwater is an intern for the Wyoming Livestock Roundup. Send comments on this article to roundup@wylr.net.