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Common Parasites Plague Sheep And Goat Herds

The barber pole worm is nearing outbreak levels in some areas of the province, according to Manitoba Agriculture, Food and Rural Initiatives (MAFRI).

The situation on a few farms is the worst I ve seen in my time here, said Mamoon Rashid, MAFRI sheep and goat specialist. He said the parasite, along with liver flukes, is affecting sheep and goats in the some regions of the province significantly.

It s pretty much a chronic problem, but this year has been a perfect year for them, as hot weather is a perfect environment for the worm, Rashid said, adding he has seen losses to the worm occur this summer.

He noted excessive and non-strategic use of currently available dewormers has resulted in worms adapting and becoming resistant to treatment. Although the American Food and Drug Administration has recently approved a new dewormer, it has yet to reach markets, meaning the last available dewormer to hit the market was released in 1981.

The specialist noted Manitoba s frigid winters play a major role in clearing some worms during periods of -20 C and below, but the worms also have the potential to go into dormancy during these months.

Symptoms of barber pole worm include anemia and soft swelling under the jaw, Rashid said.

Liver flukes whitetail deer fluke or Fasciola magna have also been hovering at outbreak levels in the southeast part of the province, negatively impacting sheep and goats. Wet grazing areas, a certain type of snail and whitetail deer are a must for the worm cycle to complete. This particular fluke can also affect cattle, but it is fatal to sheep and goats.

When liver flukes have reached their adult stage, the infection has entered a terminal phase and will result in animal fatality if not treated, Rashid said.

He noted liver flukes cause extensive damage to the liver and have the ability to drain blood at two cc per day. They can also clog bile ducts. Infected animals shed thousands of liver fluke eggs a day, continuing the cycle of infection, while also being at risk of secondary infections such as black disease caused by clostridium novyi.

The specialist said broad-spectrum medicines such as Fasinex (trichlabendazole) can kill liver flukes at all life-cycle stages, but are not available in Canada or the U.S. However, they can be imported using an emergency drug release (EDR) application approved and filled out by a veterinarian.

Drugs like Valbazen and Ivomec Plus kill only mature liver flukes, so timing is critical, said Rashid, adding even if adult flukes are killed by these dewormers, the extensive damage they have caused can still be fatal.

Rashid noted prevention of liver flukes can be aided by avoiding wet grazing areas, controlling snail populations and keeping deer, elk and moose out of pastures.

Lucien Lesage, chairman of the Manitoba Sheep Association, says he

hasn t heard much from producers regarding

worms and flukes this year, but isn t surprised it is an issue for some regions of

the province. Last year

they were an issue too, and given

the weather this year, the conditions are right, he said.

The farmer said producers are lobbying at the federal level to obtain access to more effective drugs for the treatment of liver flukes. But so far there has not been much success.

There is no push from the pharmaceutical companies for approval either, because we re a small market, he pointed out.

However, Lesage said that the unapproved treatments still end up in the Canadian food chain because it accepts lamb for slaughter from countries where the drugs have already been approved.

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About the author


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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