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Tackling parasite resistance in western Canadian beef cattle

Tackling parasite resistance in western Canadian beef cattle

Sask. Ministry of Ag tests strategic deworming program

By Kate Ayers

Staff Reporter

Saskatchewan Ministry of Agriculture Livestock specialists are highlighting the practical findings for producers from a strategic deworming program study. 

Parasite resistance is a growing concern in Western Canadian beef cattle. The level of absorption of pour-on dewormers in the bloodstream varies. This inconsistency offers reduced protection against parasites in the stomach and intestines, according to yesterday’s Saskatchewan Ministry of Agriculture article.

Parasites that survive the deworming treatment continue to produce eggs and these offspring have a higher chance of becoming resistant to the compounds they encountered. 

Many deworming products also have similar modes of action, which increases the likelihood of parasites developing resistance, according to the article.

Ivermectin dewormers, for example, are becoming less effective on parasitic populations in beef cattle. Between 30 and 60 per cent of herds showed sub-optimal efficacy when producers used this type of product, according to a University of Calgary report.

To gain a better understanding of effective deworming programs, Saskatchewan Ministry of Agriculture and Merck Animal Health conducted a three-year trial at the Western Beef Development Centre. Integrating Safe-Guard, a deworming product containing fenbendazole, into a strategic deworming plan in the spring on cow-calf pairs reduced the prevalence of parasites, according to Merck Animal Health. (The control group received one treatment of an ivermectin pour-on in the fall.)

Participants “reported a net return of $22.37 per calf in their strategically dewormed groups,” the article said.

Indeed, producers can help ensure that fenbendazole remains effective longer into the future.

“We probably are going to see some level of resistance start to increase over time. But the best way to ensure that you’re going to prolong that period, before we see that high level of resistance starting to show up, is by using strategic deworming methods,” Naomi Paley, regional livestock specialist with the Ministry of Agriculture, said to today.

“And so that’s by using several different products, and using them at specific times of the year, to try and decrease the amount of parasite eggs that are actually shed onto pasture.” This approach will decrease your reinfection rates as well, she explained.

In North America, parasitic worms cost the cattle industry around $2 billion annually, according to the article. “That (loss) would include loss-feed value, poor gains, immune suppression, and weak and sick calves – all of those sub-clinical production losses,” Paley said.  

 Previous coverage on research into drugs to treat pathogens in cattle can be found here