Cattle grazing in open pastures are inevitably exposed to internal parasites, which can lead to production losses and potential health issues. Effective parasite management is crucial to maintaining herd health and optimizing productivity. While various oral, injectable, and pour-on deworming products are available, strategic timing and proper application are key to minimizing reinfection and maximizing effectiveness.
The Importance of Proactive Deworming
Many cattle producers make deworming decisions based on an animal’s appearance. However, by the time visible signs of parasitism appear, significant economic losses and health compromises have already occurred. A strategic deworming program considers herd exposure, seasonal patterns, and reinfection risks to achieve optimal parasite control. Managing both the pasture and the animal is essential in breaking the parasite life cycle.
Understanding Parasite Exposure and Lifecycle
- Worm larvae survive through winter and remain infectious until late spring.
- Warm, wet weather enhances worm larvae viability and proliferation.
- Springtime pasture larvae populations can reach high levels, increasing disease risks in cattle.
- Once ingested, larvae mature into adult worms, lay eggs, and further contaminate the pasture through feces.
- The Ostertagia species can encyst in the abomasum wall and later release large larvae populations, overwhelming the intestinal tract.
- Infected cows contribute to pasture reinfection, impacting calves that are more susceptible to parasitic effects.
Strategies for a “Parasite-Safe” Pasture
- Kill adult worms before turnout – Reducing the initial parasite load before grazing helps prevent pasture contamination.
- Eliminate immature worms before egg shedding – Timely treatments disrupt the parasite lifecycle and reduce reinfection.
- Align deworming treatments with grazing patterns – Applying treatments at the right time is essential for effective control.
Recommended Deworming Schedule
- End of Grazing Season: Deworming after the first frost can prevent overwintering of parasites and may also eliminate external parasites.
- Early Pasture Turnout: Treat cattle a few weeks after turnout to eliminate newly acquired worms before they mature and lay eggs, reducing pasture contamination.
- Young Animal Treatments: Calves and young animals are highly susceptible to parasites. Treat them 3-4 weeks after turnout and continue treatments at 3-4 week intervals to prevent egg shedding.
- Intensive Grazing Considerations: Higher grazing pressure increases parasite exposure, requiring a more rigorous deworming strategy.
Additional Pasture Management Practices
- Dragging pastures to break up fecal pats can reduce worm larvae survival.
- Rotational and intensive grazing systems should incorporate a tailored parasite control program to prevent high reinfection rates.
Veterinary Consultation for Optimal Control
For best results, consult a veterinarian to:
- Select the most appropriate deworming product for each season.
- Integrate deworming with other herd management practices such as vaccinations and pregnancy checks.
- Develop a long-term parasite control plan tailored to your herd and pasture conditions.
Strategic deworming is essential for maintaining healthy, productive cattle and minimizing economic losses due to parasitism. By implementing timely treatments, pasture management practices, and veterinary guidance, producers can create a sustainable approach to parasite control.
