Cattle exposed to parasites while grazing can experience production losses and health issues. Internal parasite control can be achieved with various oral, injectable, or pour-on deworming products. However, relying on cattle appearance to decide when to deworm is risky, as visible effects of parasitism indicate significant economic loss and compromised health. Strategic deworming is essential to reduce reinfection, targeting both the animals and their pasture environment.
Key points to consider:
– Worm larvae can survive winter and remain infectious until late spring.
– Warm, wet weather enhances worm larvae survival.
– Spring pastures often contain high worm larvae populations, leading to cattle disease.
– Ingested larvae mature into adult worms that lay eggs, further contaminating the pasture.
– Specific worms, like *Ostertagia*, can encyst in the cow’s stomach and later release large numbers of larvae into the intestines.
To maintain “parasite-safe” pastures:
1. Kill adult worms before grazing begins.
2. Eliminate immature worms before they shed eggs.
3. Time treatments based on grazing patterns.
Cattle should be dewormed at the end of the grazing season to prevent worm carry-over and a few weeks after being put on pasture to reduce pasture contamination. Deworming young animals every three to four weeks after turnout is recommended, as they are more susceptible to parasites.
Managing pastures, such as dragging to break up fecal pats, can help reduce larvae numbers. Intensive grazing practices heighten the need for careful parasite control. Consulting a veterinarian ensures appropriate dewormer use and integration with other herd management practices like vaccination or pregnancy exams.
