Guard your grass to prevent ergot poisoning

It is springtime. I got some rain. The grass is growing. I can see my feed bills fading away.

While I reflect on my enviable state, alas, something inevitable intrudes to thwart my joy—the likelihood of ergot infections. It’s a real concern for livestock producers this time of year. Ergot is a fungus that grows on the seed heads of grasses and cereal grains, infecting only unfertilized flowers. For susceptible grasses to become infected, the fungal spore production has to coincide with flowering. Cool wet springs, followed by hot early summers provide the perfect conditions for ergot fungus to grow.

The problem lies in the production of toxic ergot alkaloids, which can poison cattle. The specific type and toxicity of these alkaloids vary based on the particular species of fungus, the environmental conditions and the type of plant being infected.

Rye is the grain most associated with ergot, but many plants can be infected, notably barley, wheat, oats, brome, fescue, timothy, bluegrass and other grasses. Fescue should be watched carefully as endophyte-infected stands produce similar toxins as ergot, and the effects of both can combine.

Ergot fungus makes a sclerotia—a dark-brown, purple or black mass—within the seed head. These masses are often larger than the typical seed and are easy to see, but you have to know what you are looking for. These fungal masses will eventually fall to the ground where they can overwinter. Unfortunately, there is no good way to get rid of ergot fungi in a pasture. Climate conditions will determine the incidence and severity of outbreaks and can vary year to year.

Ergot poisoning causes vasoconstriction, which can lead to nasty effects, notably difficulty in thermoregulation and summer slump. Cattle with ergot poisoning will often spend extended periods standing in available water or shade, lose weight and develop a rough hair coat. Gangrenous ergotism, also called fescue foot, can develop in the legs and tail. Cattle will usually be lame in the hind limbs first. If not removed from the ergot toxin in time, the animal will eventually slough its hoof. Tissue death in the ears and tail can also occur. Decreased milk production can occur. Nervous symptoms such as tremors or hyperexcitability are sometimes reported from ergot poisoning.

In diagnosing ergot poisoning, lame cattle should be evaluated to make sure they aren’t suffering from some other problem that would account for their symptoms, such as footrot, a trauma or fescue toxicosis.

Treatment of ergot poisoning is simply removing the animal from ergot toxins. If caught early and animals are removed quickly, they will recover quite well. However, if gangrene has set in or the clinical signs have gotten severe, there isn’t much to be done to solve the problem.

Better than treatment, prevention of ergot poisoning can keep animals on track. Cattle are more at risk than small ruminants because they either don’t notice it as much or are so focused on selectively grazing that they consume a lot of ergot fungus. Regular evaluation of the pasture or hay can let you know if ergot sclerotia is present. If it is, cattle should be removed.

Grass that has formed a seed head can be clipped before letting cattle graze. Because the ergot fungus only infects the seed head of the plant, clipped pastures are much safer for cattle to graze. Be careful with hay produced from ergot-infected grass. While the fungal masses that are the main cause of the problems often drop off the grass as it is being handled, the hay should be inspected to make sure it is clean.

For more information on pasture management to help mitigate issues with ergot infections, visit with your MFA solutions provider. Consult your local veterinarian for assistance in diagnosing or treating cattle that are showing symptoms of ergot poisoning.    

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