by Danielle Beard
Parsons, Kansas —
“I’m a worm guy,” said Tom Yazwinski, DVM, department of animal science, University of Arkansas, in his opening statements at the recent Boehringer Ingelheim sponsored Missouri Beef Summit.
With spring in full swing, worms are highly active, leaving livestock at risk.
“The more worms you have on your farm the less animals you have,” Yazwinski stated.
According to him, the effects of intestinal worms in cattle will vary depending on the age or stress level of the animal. However effects can include — losses in productivity, blood mineral protein tissue loss, reduced feed efficiency, reduced and/or diverted immune competence as well as an introduction to second pathogens. More visible signs can include anorexia, roughness of coat, anemia, edema and diarrhea.
“What makes worms so stressful?” Yazwinski asked. “It’s all a numbers game.”
Typically, a female can lay 50 to 2,000 eggs a day.
Another characteristic worms have going their way is survivability. On pasture they have shell protection, dung protection, mobility and anhydrobiosis (the ability to survive without water).
“Once in the animal, worms can survive through seasons, by staying sub-clinical and developing resistance,” he explained.
“So how do we control them?” Yazwinski proposed.
Pasture management and anthelmintics (dewormers) are two methods that can effectively reduce internal parasites.
According to K-State Research and Extension, pasture methods designed to reduce third-stage larva populations include the following:
•Move susceptible younger cattle to a ‘safe pasture.’ Safe pastures are recognized as pastures that have not been grazed in over 12 months, as well as small grain pastures developed from a prepared seedbed. Parasite contamination drops when a pasture lies untilled and is plowed. It is also important to deworm cattle before moving them to a ‘safe pasture’ otherwise, it will also become contaminated.
•Leave mature cattle on contaminated pastures. Under a good nutrition program, mature cows develop acquired immunity to parasites, and are much less likely to become affected by their presence than young cattle or calves.
•Do not overgraze pastures. Parasites and their larva can be found on four inches of forage closest to the ground. Animals on overgrazed pastures graze closer to the ground, therefore, picking up more larva.
The other type of parasite control — dewormer — is an excellent tool, but must be treated with caution. If used incorrectly, worms will develop a resistance, Yazwinski cautioned.
“Cattle should be wormed in the spring or fall when worms are most active,” he said. “The problem is most producers worm their cattle when they are already working them for another purpose, instead of worming them when it is most effective.”
“Make sure you are giving the correct doses, as to not build resistance to parasites. The most efficient way is to weigh each animal before administering the dewormer, but if you can’t weigh each then find approximately the largest, weigh it, and vaccinate everyone else based off that dosage,” Yazwinski advised.
While Yazwinski explained the importance of choosing a name brand dewormer over generic, K-State Extension says it’s important to also keep the following in mind when selecting a dewormer:
•Type of animal being treated (calf vs. cow, beef vs. dairy)
•Ease of application
•Broad spectrum of control (immature, mature, inhibited)
•Slaughter/milk withdrawal time
Yazwinski also offered his own tips to producers. “Do egg counts. It’s important to see how much you’re working with, and if what you are using is working. Treat calves at weaning and treat cows right before they freshen. Treat stockers as soon as you get them. Rotate products each time you treat a set of calves and be diligent with long range.”
“Also, don’t treat and then move. Put cows back in their wormy pasture, this is what is going to help you dilute resistant worms,” he added.
The more worms you have, the less productive your animal is, Yazwinski reiterated. It’s imperative not only for livestock, but also for producers to treat the parasites and to do so correctly. £