Sheep producers warned to be on the lookout for deadly parasite

Expert says pasture rotation is key and since barber pole worms stay low, allowing 
pastures to grow a bit higher before grazing can help

With two hot and wet summers under their belts, Manitoba sheep producers need to be on guard against the barber pole worm.

“It’s a problem in all of North America, and actually most of the world,” said Dr. Reuben Neumier, a veterinarian who raises sheep between Virden and Pipestone.

“This is the parasite that causes the most economic problems for the sheep industry,” he told producers during an Ag Days presentation at Brandon’s Keystone Centre.

“Sheep have all types of parasites. But the ones to really worry about, the ones that cost the industry the most money, are the intestinal worms.”

Barber pole worm — a.k.a. Haemonchus contortus — originated in the tropics, but is well adapted for Manitoba’s climate, Neumier said. Because it needs moisture and heat to develop, recent warm years have increased the impact the parasite is having on Manitoba’s flocks.

Although they can also infest goats and cattle, the worm’s bloodsucking ways have the greatest impact on smaller animals. Each worm takes about half a drop of blood per day, said the veterinarian.

“Which doesn’t sound like a lot, but if you go for a month with 1,000 worms, they will suck half the blood volume that’s in a 100-pound lamb. That’s significant,” Neumier said.

The red and white parasitic worm has already gained the upper hand in states such as Alabama, Georgia, and Mississippi.

“It’s just rampant there, it’s putting people out of business,” he said.

What’s worse is that in many areas south of the border, worms have become resistant to the drugs used to treat them, he added.

Resistance hasn’t become a problem in Manitoba yet, but said producers have to be strategic when using wormers if they want to keep resistance at bay, he said.

That strategy may include only treating sheep that clearly have barber pole worm infestations.

“Seventy-five per cent of the worms are in 25 per cent of the sheep,” said Neumier.

A patented colour card system is available to producers through the Manitoba Sheep Association that allows farmers to gauge anemia based on the colour of the mucous membrane on the sheep’s lower eyelid.

Anemia, along with bottle jaw, listlessness, and death are signs of barber pole infestations.

Strategically rotating sheep in grazing areas can also combat the spread of the worm, which transforms from egg to Stage 3 larva in fecal pellets, then spreads via surface moisture in the hope of being gobbled up by a wool-bearing ruminant.

“They live in moisture, not in sloughs, puddles and dugouts, but in the thin film of moisture on the grass and on the soil,” said Neumier.

But the larva usually stay about two inches off the ground, and rarely venture above four inches high on vegetation.

Neumier said if producers are able to keep their pastures a little on the tall side, encouraging sheep to eat higher up, they will reduce the chance sheep will ingest the larvae.

Under some conditions, such as very hot weather, rotating pastures can also allow larvae to die off while sheep are grazing elsewhere.

Gail Kasprick began sheep farming a year ago, but said her small flock will get off to a fresh start because the pasture they’re in hasn’t been used for sheep before.

“I would think that if I start off clean, it would be much better,” said the Neepawa-area producer.

She said she hopes the barber pole worm won’t become a problem for her 16 sheep.

“One of my friends has had issues with it and it really rattled her,” Kasprick said. “She had a sheep suddenly die from it… so I’ve been warned.”

Even if you worm strategically throughout the year, Neumier said flocks should be treated once for the worm between freeze-up and lambing. The barber pole worm is able to hibernate within the sheep, but doesn’t start producing eggs again until spring.

Not all sheep are equally susceptible to the barber pole worm or the blood loss it causes, however.

“Resistance is a heritable trait, so you can actually select for it,” he said.

About the author

Reporter

Shannon VanRaes is a journalist and photojournalist at the Manitoba Co-operator. She also writes a weekly urban affairs column for Metro Winnipeg, and has previously reported for the Winnipeg Sun, Outwords Magazine and the Portage Daily Graphic.

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