Internal parasites are present in nearly all forage situations, and spring turnout is a likely time for cows, calves or yearlings to become exposed to parasites. Gary Sides, PhD, cattle nutritionist for Pfizer Animal Health, says parasites require access to cattle to complete their lifecycle. “The purpose of strategic deworming is to treat cattle in a timely manner to reduce the total parasite load on pasture,” he says. “This reduces total exposure of parasites to all cattle on that pasture.” Sides adds that internal parasites suppress appetite, which limits nutrient intake and absorption. “Reduced nutrition impacts animal performance including gain, feed efficiency, immune response and reproduction.” Rough hair coats and reduced weaning weights are clinical signs of underperforming calves, caused by a parasite problem. These losses can be minimized by using a proven dewormer before pasture turnout in the spring.