Conditions Cool, damp weather in late spring and early summer increases ergot contamination
Haying is wrapping up and many herds are still out grazing, so winter feeding might not be a top-of-mind topic right now. However, it is never too early to start thinking about what grain will be used in your herd’s winter ration. It’s important to purchase the highest-quality feed grain you can. Ergot contamination is an issue to be aware of when sourcing feed grain this fall.
“Ergot is a plant disease caused by the Claviceps purpurea fungus and can be found in rye, triticale, wheat, barley, brome grass, wheat grass, bluegrass, quack grass, orchardgrass, meadow foxtail and wild rye,” says Stephanie Kosinski, forage specialist with Alberta Agriculture and Rural Development. “Ergot is most easily recognized by the hard, black bodies that replace the kernels on the seed head.”
Ergot overwinters as black, grain-sized fungal structures. In the spring, these germinate and form mushroom-like structures that produce spores which are carried by the wind to flowering cereals and grasses. Cool, damp weather in late spring and early summer increases ergot contamination due to the longer flowering time of cereals and grasses in these environmental conditions. Parts of the province may have experienced these conditions in the spring and early summer this year, creating the potential for ergot to develop.
“You should be concerned with ergot contamination of your feed grain because ergot contains numerous toxic alkaloids that will negatively affect the health of your livestock,” says Kosinski. “General symptoms of ergot poisoning include lameness, excitability, belligerence, loss of appetite and weight loss. It can take two to eight weeks for these symptoms to become visible.
“There are four specific syndromes caused by ergot: gangrenous ergotism, convulsive/nervous ergotism, reproductive ergotism and hyperthermic ergotism. The gangrenous and nervous forms are most common.”
Gangrenous ergotism is associated with longer-term ingestion of ergot. Ergot alkaloids cause small blood vessels to constrict, reducing the blood supply to limbs, tails, teats and ears. If blood flow is restricted for long periods of time, the tissues become oxygen deprived and die. Hooves can slough off and, in cold weather, ears freeze off.
Convulsive, or nervous ergotism is more common in horses and sheep, and is the acute form of ergotism. Symptoms include dizziness, drowsiness, convulsions, paralysis and death. These symptoms usually disappear about three to 10 days after the ergot is removed.
Reproductive ergotism is caused by high levels of estrogen in the ergot bodies. This can lead to abortions or lowered fertility due to abnormal cycling. Once the ergot is removed, it takes a long time for estrogen levels to return to normal.
Hyperthermic ergotism results from long-term exposure to ergot. It is made worse on hot and humid days with no shade. Animals pant and lose weight.
“The upper feeding limit of ergot in older, non-pregnant cattle is 0.1 per cent by weight of feed consumed,” says Kosinski. “Health issues could still occur at this level, so always try to feed ergot-free feed to all your cattle. Pregnant, breeding and lactating animals are the most sensitive to ergot. They should not be fed any ergot at all.
“One last thing to think about is the screening pellets or screenings you buy from your local seed-cleaning plant. Ergot levels in these screenings can be very high. Do not buy screenings with any amount of ergot unless they can be appropriately diluted with ergot-free feeds.”