Hay supplies are tight going into this fall. But, if you plant cover crops, you could be sitting on a potential feed source. Just make sure you're not doing more harm than good. A lot of common cover crops can sometimes be hazardous to herd health.

“Crops such as forage and grain sorghum, sudangrass, hybrid sorghum-sudan, and pearl millet are notorious nitrate accumulators. Canola and other brassica species, such as radishes and turnips, take up nitrogen effectively and can accumulate dangerous concentrations of nitrates,” says Kansas State University (K-State) Research and Extension crop production scientist Kraig Roozenboom.

Excessive nitrate uptake in cattle can lead to asphyxiation because it hinders the blood's ability to carry oxygen, says K-State Extension animal scientist Dale Blasi. That makes it important to test any of these crops, especially radishes and turnip tops, for nitrates before feeding them to livestock. That's even more important in drier-than-normal summer growing seasons like this one.

“The potential for high nitrate concentrations in crops such as sorghum, brassicas, cereal grains, corn, and some grasses occurs after exposure to drought, hail, frost, cloudy weather, or soil fertility imbalance,” Roozeboom adds.

• See more on nitrate toxicity