Is there something strange in your livestock herd?

MOOSE JAW, Sask. — Most of the recent unusual outbreaks investigated by the Western College of Veterinary Medicine’s disease investigation unit have something in common: cow-calf operations and nutrition.

But even the experts are sometimes stumped.

John Campbell, who heads the unit, said they are often called late in a situation after the local veterinarian has eliminated other possibilities.

The unit has existed for more than 20 years and received funding from various sources. It has conducted 84 investigations since the provincial agriculture ministry began funding it in 2007, and Campbell said there are more each year.

Investigations can be as small as making additional testing money available to local veterinarians and as large as more detailed herd visits.

Referrals must come from local practitioners.

The 84 investigations include 56 cow-calf cases, one feedlot, five dairy, seven sheep and goats, six horses, five hogs, and one each of alpaca, deer, elk and bison.

Campbell said nutrition or toxicology factor into half of the investigations.

“Nutrition is actually a pretty important welfare issue,” he told the Saskatchewan Stock Growers Association annual meeting.

For example, he said the public might be concerned about pain control during castration, but that is a small moment in an animal’s life. Nutrition problems tend to affect an entire herd.

Factors such as drought and economic hardship can affect how a herd is fed.

Campbell said margins are small in cattle production, and feed is the most significant cost.

Producers can minimize feed costs and still maintain good nutrition, but some don’t. He said these tend to be chronic, long-term issues, and high levels of mortality can occur.

Nutritional welfare includes protein and energy malnutrition, lack of access to adequate water and vitamin and mineral deficiencies.

“We don’t see a lot of (malnutrition),” Campbell said.

However, investigators have seen beef cows down at calving because of calcium or magnesium deficiencies, as well as problems caused by greenfeed with high potassium levels.

Then there are the more unusual causes of feed problems. Upon ex-amination, one dead animal was found with a stomach full of sand. Campbell said the cattle had been fed silage and a band of sand was found in the middle of the silage layers.

“This was a true accident with significant consequences,” he said.

A 2,000-head backgrounding feedlot was concerned about poor feed consumption, low weight gain and excessive salivation. Eighty percent of the cattle were affected, and many had oral lesions.

“It’s all because of foxtail awns in the silage,” Campbell said.

The awns had to be physically re-moved from the teeth to cure the lesions.

Campbell said nutritional issues are complicated. Producers can be in denial and believe that something else is causing the problems.

“They do not want to accept that the feeding program is at fault,” he said.

Lead poisoning from old batteries continues to be a common problem with food safety implications. Ergot, selenium, sulfate or monensin toxicity and blue-green algae poisoning are also problems.

A more unusual toxicological case involved a 220-head commercial herd that was swath grazing oats and receiving one bale of grass hay every three days.

A new pallet of mineral was delivered about six weeks into the swath grazing period, and the manager noticed it was a different colour and decreased intake.

The cows moved to graze corn about a month later while the heifers stayed on the oats.

The problem occurred several days later when 35 to 40 of the cows were stiff or lame in the hind end. Several were discovered blind. The cows were removed and the corn was examined. It contained a lot of mould because of fall and late winter rain.

“We think that mould had a toxin in it that was affecting the optic nerve,” Campbell said.

However, the toxin hasn’t been identified and the syndrome has not been previously described.

Other investigations have involved reducing vaccines to save money and reproduction problems caused by infections. Campbell said a producer who did not vaccinate for blackleg and lost 60 calves makes a good case for vaccines that cost pennies a dose.

He also said there will always be unknowns and bad things happen even in herds that are well managed.

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