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Parasite resistance studied

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Published: May 28, 2015

Western Canadian sheep producers are being asked to volunteer their flocks for the next phase of a research project involving sheep parasites and parasite resistance to common treatments.

Alberta Lamb Producers issued a recent call to members asking those with more than 60 ewes to participate.

Last summer, researchers Michel Levy and John Gilleard of the University of Calgary surveyed 20 farms to identify the type and number of parasites present, the organization said.

“The results of this work … suggested that many Alberta sheep flocks have high parasite burdens and that ivermectin and fenbendazole/albendazole resistant parasites may be more common than previously thought in the province.”

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The researchers now plan a more comprehensive three-year study of the problem using funding from the Alberta Livestock and Meat Agency.

They plan to approach Alberta producers who participated last year, as well as other sheep producers in British Columbia, Saskatchewan and Manitoba.

“This year the project will continue to look at parasite burden and at the efficacy of treatment at the flock level,” said a news release from Alberta Lamb Producers.

Levy, Gilleard and veterinary medicine student Lana Swain prepared a report on last year’s research, which said the 2014 pilot study suggested parasite burdens in Alberta sheep are higher than expected and that resistance to common treatments is an issue.

They said sheep producers in Western Canada are seeing higher incidence of anemia, lethargy and mortality in lambs because of roundworm infection.

“This is now a major threat to both sheep welfare and production and has the potential to limit attempts to expand and/or intensify sheep production in the region,” said the report.

No specific study of sheep parasites has been conducted for more than 20 years, and information is lacking on the prevalence of different parasite species, their distribution and their resistance to major drug treatments, known as anthelmintics.

In background information provided to the lamb group, the re-searchers said roundworms “are the most important disease problem of sheep throughout the world.”

The parasites cause two main syndromes in sheep: parasitic gastroenteritis and haemonchosis.

The former illness reduces weight gain and sometimes causes diarrhea. The latter causes acute anemia, swelling under the jaw and lethargy. Both are most commonly seen at the end of the grazing season.

Haemonchosis is caused by haemonchus contortus, also known as barber’s pole worm, and is particularly able to develop resistance to common drugs used to treat sheep parasites, the researchers said.

For more information, contact Levy at mlevy@ucalgary.ca and Gilleard at jsgillea@ucalgary.ca.

About the author

Barb Glen

Barb Glen

Barb Glen is the livestock editor for The Western Producer and also manages the newsroom. She grew up in southern Alberta on a mixed-operation farm where her family raised cattle and produced grain.

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