Ergot is an infection of grasses and cereal crops caused by the fungus, Claviceps purpurea. The oversized purplish-black ergot bodies that develop in the place of seeds or kernels can be easily identified in standing crops and uncleaned grain, but it’s a different story once the grain has been processed and one with which Wayne Brost of Medicine Hat, Alta., is all too familiar.
Though Brost doesn’t grow grain, he knows ergot when he sees it. He clearly remembers his dad checking the crops for ergot, especially rye because it is highly susceptible, but he never imagined that commercial feed could be contaminated with ergot — one would expect it would be tested to ensure it’s free from toxins. As he found out, that’s not the case.
Ergot bodies contain several types of claviceps alkaloids which are toxic to people and animals when consumed as they cause blood vessels to constrict, reducing blood flow, which can lead to gangrene, abortions and nervous symptoms. Processing contaminated grain doesn’t destroy the alkaloids but it does make ergot bodies impossible to detect with the naked eye.
At weaning last November, Brost received a fresh load of grain screening pellets, just as he has for the past eight years. The first time he fed the pellets, a few of the calves ran over to the trough and the others wandered in behind, just as he expected they would. That’s where the similarities end.
“They licked around, but they weren’t keen on it,” Brost says. This odd reaction to the pellets continued day after day and he really began to wonder what could be wrong because other years the calves would always have the pellets cleaned up by the end of the day.
Not knowing what the problem was, he sent a sample of the pellets to an Alberta lab for a routine feed test. Nothing unusual turned up.
About a month later, he noticed a few calves limping and thought it could be foot rot, but in the back of his mind he still suspected that something wasn’t right with the pellets because the calves still weren’t going after them.
When part of an ear fell off a calf as it pulled its head out of the headgate, that was it. Brost called his veterinarian who suspected he was dealing with ergot poisoning.
After examining two of the calves and consulting with the Western College of Veterinary Medicine (WCVM) in Saskatoon, Brost’s veterinarian was confident his initial diagnosis was correct.
By this time, a couple of months had passed and he had about a dozen calves limping around. He contacted the feed company, which delivered a fresh load of pellets, and the calves took to them just like any other year.
At this point, Brost sent a sample of the original load to another Alberta lab with a specific request to test for ergot. It came back negative. However, a sample the feed company sent for testing did detect ergot, but not the concentration.
Again, Brost’s veterinarian sought advice from the WCVM and learned that they needed to request a test for claviceps alkaloids, not ergot bodies. Only a couple of labs in North America currently test for all types of claviceps alkaloids. Subsequently, a sample was sent to a lab in Missouri.
“I was blown away when the test came back showing that the claviceps alkaloid level was 220 times over the acceptable U.S. limit,” Brost recalls. “When I found out, well to say the least, I was sick to think that I had fed this to the calves.” The acceptable limit in the U.S. is 100 to 200 parts per billion. The sample tested 44,000.
Altogether 15 calves lost all or parts of ears, tails and hooves. Three had to be euthanized and the feed company purchased the remainder of the calves with obvious defects.
Not only that, but before the contamination was detected he was advised by a company representative to feed some of the original pellets to his cows. They had no unusual reaction to the pellets, but he did lose a couple of bred heifers that were in the same group when they calved prematurely.
The episode still haunts Brost because the calves that received the poisoned pellets were his replacement heifers. Now he is short 15 replacements and worried about the long-term health of his remaining heifers.
Brost called Canadian Cattlemen with his story so that other producers could be made aware that ergot poisoning isn’t limited to homegrown feed. If your animals are rejecting feed, his advice is to pay attention and get it tested.
— Debbie Furber is a field editor for Canadian Cattlemen at Tisdale, Sask.
A Canadian test for claviceps alkaloids
Testing for the presence of claviceps alkaloids is about to become a whole lot easier for Canadian producers and feed companies.
Dr. Barry Blakley, the supervisory veterinary toxicologist with Prairie Diagnostic Services (PDS) housed at the Western College of Veterinary Medicine received word in July that they have been approved to submit a grant application to buy the necessary equipment. It will likely be late fall before the grants are announced, and another couple of months to get the equipment in place.
PDS recently expanded its animal health and pathology services to include tests for heavy metals, vitamins and minerals in blood, tissue and feed. The new equipment will test for organic compounds such as claviceps alkaloids and other mycotoxins plus herbicide, insecticide and rodenticide residues in feed.
Blakley used to field a couple of calls a year about ergot. Now, with the wet weather conditions of the past few years, he averages that many every week.
High levels of ergot poisoning affect the production of prolactin, a hormone involved in mammary gland and milk development during pregnancy. Fortunately it is not a chronic condition and the next lactation will be normal.
Higher ergot levels may cause hallucinations but the animals generally recover after a day or two off the contaminated feed.
There is no recovery from the severe gangrene that results in the loss of body parts.
Up until the PDS is ready to test for mycotoxins, Blakley is available to help producers find a U.S. lab to test for claviceps alkaloids and interpret the test results according to Canadian recommendations. He can be reached at 306-966-7350, or email [email protected]
Recommended tolerance level
The Canadian Food Inspection Agency (CFIA) is responsible for the Feeds Act Regulations. As such it has the capability to test for ergot in livestock feed, but only accepts samples submitted by CFIA inspectors.
Currently, alfatoxin is the only mycotoxin regulated in Canada, however, recommended tolerance levels have been published for several others. The recommended maximum for ergot alkaloids in feed for cattle, sheep and horses is two to three milligrams per kilogram.
CFIA does monitor for mycotoxins including ergot alkaloids under the National Feed Inspection Program. Spokesperson Lisa Gauthier says they also follow up on complaints of suspected feed contamination by contacting the feed manufacturer or farm where contaminated samples are collected. The facility or farm then needs to investigate the source of the contamination and take appropriate corrective actions.
The Canadian Grain Commission allows 0.1 per cent ergot bodies by weight for most classes of No. 1 wheat and durum delivered to elevators, and up to 0.10 per cent for feed wheat. The maximum for No. 1 and No. 2 general-purpose barley is 0.025 and 0.10, respectively, while malting varieties range from zero in the top grade, to 0.025 for select and no limit for standard select. The maximum for rye is 0.05 per cent. For triticale it is four kernel-sized pieces in a 500-gram sample.
According to the Saskatchewan Ministry of Agriculture, the recommended maximum level for ergot bodies in cattle feed is 0.10 per cent (by weight) of the animal’s daily dry matter intake. Open-pollinated plants including rye, triticale and some grasses (wheat grass, quack grass and smooth brome) are most susceptible. Wheat and barley can be affected, but ergot is seldom seen in oats.
Young and pregnant animals are highly susceptible to ergot poisoning. The severity and extent of damage to their body depends on the concentration of the alkaloids in the feed as well as the length of time the contaminated feed is fed. It may take two or three weeks for symptoms to become noticeable.