Grazing animals are exposed to parasites throughout the grazing season. Both external and internal parasites can infest animals and impact the health and performance of grazing livestock.

A new Iowa State University Extension publication Internal Parasites in Grazing Ruminants, IBCR 203, focuses on understanding and controlling these challenges in grazing cattle. It is written by Claire Andresen, graduate assistant in animal science, and Troy Brick, DVM, assistant professor of veterinary diagnostic and production animal medicine at Iowa State.

The publication focuses on different ways to keep herds healthy, including good pasture management and deworming.

Keep worms from robbing profits
“Deworming is an important production practice for cow-calf producers,” Brick says. “Research has shown that not using dewormers could negatively impact breakeven prices by as much as 30% per head each year. This includes impacts on weaning rate, pregnancy rate and survival rate of the calf.”

This treatment is especially important for animals that are most susceptible to parasites, including all bulls, yearling animals, stocker and replacement heifers, and 2-year-old cows.

“While suckling calves aren’t as high risk as weaned calves, it can still be beneficial to treat pre-weaned calves between 200 and 400 pounds,” Brick notes. “In a cow-calf setting, treating only cows typically provides adequate protection for calves.”

The publication also has information on pharmaceutical options available to producers for parasite protection. A table included in the publication provides a comprehensive list of drugs available, proper dosage, mode of administration and withdrawal time. The specific species of parasites each product targets is also included.

“Working with your local veterinarian to identify predominant worm species in your herd, selecting the proper dewormer to treat them and using good pasture management practices will result in a well-rounded parasite control program for your herd,” Brick says.

Source: Iowa State University