Interpretive Summary: Current and future trends in managing internal parasites in forage-based livestock

By: Joan Burke

Gastrointestinal nematodes or worm parasites in grazing livestock and horses are a major health challenge due to worldwide prevalence of the parasite’s resistance to available dewormers. Pharmaceutical companies have limited interest in development of new products because of cost and the likelihood that worms will develop resistance to new compounds and continue to market older dewormers. Small ruminants have an immediate threat of parasite infection from barber pole worm or Haemonchus contortus, a blood-sucking nematode parasite whose life cycle includes adult egg laying in the stomach or abomasum and egg hatching and larval development on pasture. Cattle nematode parasites are less pathogenic, though can lead to lower body weight gains in younger animals, and anthelmintic resistance of these parasites is a growing concern. Few cattle producers are aware of dewormer resistance. Many veterinarians around the world continue to offer antiquated recommendations to their farm clients of frequent administration of dewormers, unaware of the extent of dewormer resistance, or the value of alternative worm management strategies. This is because few veterinary parasitologists exist, older veterinarians understood the value of anthelmintics and mentor their young veterinarians to give the same recommendations. Few veterinarians are knowledgeable about small ruminants due to limited economic incentives to work with these farmers.

Read the full article in Animal Frontiers.