Spring Deworming Leads to Success

Although still a relatively new parasite management practice, more and more southern beef producers and industry specialists are recognizing the value of strategically deworming in the spring to help combat the negative effects of parasites. They are finding that spring deworming is key to overall herd health, weight gain and profitability.

According to Steve Wikse, DVM, associate professor of large animal medicine and extension veterinarian at Texas A&M University, College of Veterinary Medicine, the most effective time to deworm calves and cows in the south is during the late spring. Twelve Texas field trials, conducted between 1990 and 1997, proved that deworming spring-born beef calves at 200 to 300 pounds increased their weaning weights by an average of 25 pounds, said Wikse.

“March, April and May are the heaviest months for pasture contamination with infective larvae and thus are the months that cattle acquire the greatest level of worms,” Wikse said. “We typically recommend deworming twice a year – in the fall and spring.”

Beef producer Herman Walker, Herman Walker Farms, Paxton, Fla., said he’s seen the benefits of deworming twice a year firsthand. Walker strives for high performing cattle and deworms his 750 stocker cattle upon arrival. For his 500-head cow herd he deworms during processing in the early spring and again at weaning during the early fall season. He estimates the second deworming gives him anywhere from a quarter of a pound to half a pound more a day in weight gain.

According to Robin Falkner, DVM, senior veterinarian, Pfizer Animal Health, a sound deworming strategy is based not only on killing large numbers of parasites that have accumulated in cattle, which fall-only deworming accomplishes, but on preventing cattle from becoming infected with worms in the first place.

“If your pastures are clean, a single spring deworming will kill the parasites in your incoming calves and will reduce pasture contamination,” said Falkner.

“By deworming in the spring when parasite counts are low, we actually have the greatest effect on the number of parasites that would potentially accumulate on pastures and infect cattle and calves over the coming summer and early fall,” Falkner said. “If we can deworm before the pastures become contaminated with eggs and larvae, then we can break the transmission cycle and reduce performance losses due to internal parasites.”

But if your pastures have grazed cattle that weren’t dewormed, those cattle likely shed parasite larvae that are waiting on blades of grass to be ingested and infect a calf.

To stop further pasture contamination and to effectively “clean” that pasture, Falkner recommends two dewormings, strategically placed fairly close together. By deworming cattle in the spring or when they are turned out, then again 30 to 45 days later, you not only kill any existing worms in the cattle, but you also kill the larvae they have ingested in the first 30 days of grazing, explained Falkner. “Spring Deworming makes a whole lot of sense to reduce overall pasture contamination and reduce the presence of worms in your cattle.” ©