Veterinarians were confronted with a disturbing sight of animals hobbling on sore feet last winter when the Lethbridge Animal Clinic received a call to check on lame cattle at a local feedlot.
The eventual diagnosis was high levels of ergot in the feed, but in the early days the veterinarians were not sure what was wrong, said practitioner Aaron Gibbons at the University of Calgary’s veterinary medicine conference in Calgary.
The feedlot had unknowingly fed a triticale-rye screenings mix contaminated with ergot.
The feed had been sampled, but a more sophisticated test at a lab in Oregon determined ergot levels were 3,500 parts per billion, when a safe amount would be 400 to 700 parts per billion.
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“Ergot can be a very significant problem if we are not watching for it,” Gibbons said.
Producers should receive a sample from every load of feed and should not be afraid to reject it, he added.
“The best scenario is not feeding it at all, but if you do have it, make sure you dilute it out.”
Ergot is a fungus that grows on cereal grain, most commonly rye and triticale but it was also found in barley and durum last year because of cool, moist growing conditions.
Alkaloids in the kernel causes the problem. They damage the muscle layer around large arteries, which becomes deformed, damaged and scarred. Blood vessels will constrict if there is enough exposure to the alkaloid, and over time there is permanent damage to the arteries. Blood flow is inhibited as the arteries constrict.
Gangrene eventually develops in the extremities because of lack of blood flow. Ears, tails and feet slough off. The hind legs are especially affected because they are furthest from the heart.
The affected feedlot had 1,500 steers placed in October. They were on full feed. One thousand heifers had been placed earlier and 3,500 background calves were also present.
Some lameness appeared in the heifers in December, and the yard manager was treating foot rot that did not respond.
The vets also suspected at first that the steers might have the intestinal problem acidosis, which can cause laminitis.
By January, they started to see severe hind end lameness among the steers within a couple weeks of receiving the feed.
Some cattle were hobbling on swollen feet and in one case, an animal was walking on a frozen stump because the hoofs were gone.
“There was no pain anymore and they actually got around pretty well, but they were walking around on a stump,” Gibbons said at the June 20 conference.
The situation was exacerbated by extreme cold with nighttime temperatures below -30 C.
About 10 animals were euthanized in one day. Five percent of the 1,500 steers were eventually put down.
