Testing is important | Ergot is among the major threats that can cause widespread damage
SASKATOON — Chris Clark will never forget the day he rolled a cow over and its two hind feet stayed behind.
“The legs had actually completely separated,” said the Western College of Veterinary Medicine professor.
“It is a particularly unpleasant thing to have to deal with.”
He and colleagues were investigating a complaint from a producer that many of his cows were lame. It was a cold January and some cows were so lame they had to be trucked to the yard from the pasture where they were being fed hay and screenings.
Clark said when he arrived the animals seemed quite content. They were eating, drinking and ruminating but would not stand up.
“As we started to look at more, almost every animal lost a foot or was in the process of losing a foot,” he said.
Sixty animals were euthanized because they lost their legs, and more losses followed.
“It almost makes you gag when you see how bad the legs are,” he said.
Clark said ergot poisoning was the only possible explanation, even though the feed was long gone.
Ergot poisoning in humans typically presents in the brain.
The mycotoxin is a chemical relative of LSD, and cases have been documented for 1,000 years that could be explained by ergot poisoning, particularly in rye.
“It’s a pretty wicked acid trip, by all accounts,” he told the Saskatchewan Beef Industry Conference.
However, ergot poisoning in cattle shuts down the blood vessels to peripheral areas such as the feet and tail and acts like a tourniquet.
He said extremities will hurt and go numb when the condition occurs in warm weather, but there is a chance of recovery.
However, limbs will freeze solid and die when it occurs in cold weather of –40 C.
Clarke said the producer he worked with had obtained screenings from a local elevator, but the employee who inspected the screenings for ergot before they were sold was away for three weeks and the feed was not examined.
There is zero tolerance for ergot in grain for human consumption, which means contaminated grain automatically becomes cattle feed.
The legal limit is .3 percent in a 500 gram sample.
“That might be a big generous,” Clark said.
“Generally you probably want to look at getting your ergot levels under .1 percent.”
He said counting the ergots in a sample isn’t good enough because the amount of toxin within the ergot is the problem.
Ergot has become a bigger concern in the past few years, likely because of wet, cool springs.
The disease begins with a spore in the ground, which must be frozen. It germinates in spring and produces a pollen-like substance that infects open pollination plants such as rye and triticale.
However, it can also get into weeds and other crops such as wheat and oats.
Clark encouraged producers to be careful when feeding grain, particularly elevator screenings. Testing feed for ergot at the veterinary college costs $63.
The feed can be diluted, but Clark said seed cleaning does not eliminate the ergot.
Dicoumarol is another mycotoxin that cattle producers should worry about.
Sweet clover naturally contains a compound called coumarol. When the clover is cut for hay or silage and becomes mouldy, the mould can act on the compound and create dicoumarol.
Dicoumarol is a powerful anticoagulant that stops blood clotting.
Cattle that eat dicoumarol risk bleeding problems, Clark said.
“If a cow is mildly affected, her newborn calf is going to be severely affected,” he said.
The trauma of passing through the birth canal could cause bleeding. Cows will also be at risk they have any type of laceration from giving birth.
Bruising can also result in uncontrolled bleeding.
Clark said producers should consider their feed source if they see large swellings from pooling blood, animals that are reluctant to move and bruising around joints.
Affected cattle will have pale eyes and mouths because the blood is draining from their circulation systems.
Clark said suspected cases should be referred to veterinarians, who can test clotting ability.
“If you’ve got high value stock and you want to do something to save them, treating with vitamin K is very effective,” he said.
“Vitamin K provides the raw materials for the cow to make its own clotting factors.”
However, avoiding the poisoning in the first place is easiest. Clark said mould is a problem in sweet clover.
“If you see mould, get rid of the stuff that’s mouldy,” he said.
“Don’t just expect cows to sort through (the feed).”
Producers who believe their feed might be contaminated should dilute it at least three to one, he added.