Identify and Treat Cooperia in Calves to Improve Performance

Cooperia spp. is one of the most common intestinal parasitic roundworms to infect calves.

Cooperia spp. is one of the most common intestinal parasitic roundworms to infect calves. Yet, many beef producers may be unaware they have a Cooperia problem.

“Cooperia has increasingly become an economic issue during the past five years,” said Dr. Jody Wade, professional services veterinarian, Boehringer Ingelheim. “Only recently have these internal parasites drawn more attention. As cattle are dewormed more frequently, we are finding more Cooperia in cultures.” With Cooperia parasites on the rise, so are the cases of Cooperia resistance to dewormer – primarily macrocyclic lactones dewormers, common in pour-ons and injectables.

Estimating economic loss to Cooperia is not easy, but there is proof that dewormers can be effective against the threat of loss. An academic assessment of production impacts of internal roundworm parasites completed in North America in 2007 confirmed the value of dewormers.¹ The study evaluated the economic impact of parasite control versus the use of growth promoter implants, sub-therapeutic antibiotics, ionophores and beta agonists, and found deworming had the biggest positive impact in cow-calf pairs (23 percent for weaning rates) and stockers ($20.77/head in breakeven prices.)

Dr. Wade said that age of the host animal appears to be a factor in the degree of impact. Young calves are highly susceptible to Cooperia until their second grazing season, where they begin to shed fewer eggs and effectively limit the populations of Cooperia on their own.

“University research has confirmed bigger numbers of Cooperia in fecal egg counts in recent years, as well as a negative impact on weight gain,” he said.

A study designed by the University of Minnesota assessed the effects of a pure Cooperia infection on feed intake, growth and productivity of steer calves. The study found that Cooperia affected weight gain by 7.4 percent, with parasitized animals consuming 1.5 lbs./day less feed.2 Another key finding was the effect Cooperia had on overstimulating and enlarging the mesenteric lymph nodes, responsible for local immune function of the lower GI tract (intestines). This effect takes a tremendous amount of energy away from growth, and can also suppress and shutdown immune function needed to fight respiratory diseases.

While producers may not visually realize the loss of a quarter of a pound of weight gain per day to Cooperia, Dr. Wade noted that adds up to 25 pounds of lost gain over 100 days.

“That is a dramatic economic difference,” he said.

Dr. Wade suggested producers invest in fecal egg counts when they suspect poor performance or see such clinical signs as a rough hair coat, diarrhea or bottle jaw.

“My advice to producers is to work with veterinarians to perform routine fecal counts. You want to confirm your dewormer is working effectively,” he said. “Cooperia maybe resistant to treatment with pour-ons and injectables, but can still be susceptible to treatment with a benzimidazole, or white wormer, like Synanthic^® (oxfendazole) Bovine Dewormer Suspension.”²

He added that evaluating internal parasite infestations with fecal egg count reduction tests (FECRT) is a good starting point. FECRTs assess the effectiveness of products being used and can help detect if you have parasite resistance in your herd. Two sets of fecal samples are taken from your herd, after the first sampling, treat according to your veterinarian’s recommendation. Then, come back in 14 days to take another set of samples from the same group of cattle, and calculate the reduction in egg counts, before and after deworming.

“Do this test on 20 percent of your herd, or 20 animals, whichever is fewer,” Dr. Wade added. “We want to see a 90 to 95 percent fecal egg production reduction.” Less than that would suggest a resistance population is present.

If the FECRT test falls below 90 percent reduction, work with your veterinarian on possible additional testing to determine the predominate worm species that are resistant to your dewormer.

Not only is it important for producers to be strategic in selecting the right dewormer(s) to use, he recommends producers weigh calves to administer the right dose.

“It can be easy to underdose an animal,” he explained. “In addition, producers and their veterinary consultants should be prepared to utilize additional diagnostic tools if needed to effectively control cattle internal parasites like Cooperia.”

SYNANTHIC RESIDUE WARNINGS: Cattle must not be slaughtered until seven days after treatment. Because a withdrawal time in milk has not been established, do not use in female dairy cattle of breeding age.