By Andi Anderson
Spring brings fresh pastures and growth, but it also signals the rise of internal and external parasites in beef herds. While many producers apply deworming products, recent research asks, “Are you truly controlling what you think you are?”
In 2023, the University of Kentucky Cooperative Extension, Kentucky Beef Network, and Merck Animal Health collaborated to assess parasite levels and treatment effectiveness in beef herds.
Over 180 fecal samples were collected from both mature cows and growing calves. Producers chose their own dewormers, which were categorized as macrocyclic lactones (like ivermectin), benzimidazoles (white pastes), or combinations.
The results raised concern. Stomach worm eggs were found in 60% of mature cattle and 78% of younger cattle. Cooperia, another common internal parasite, appeared in 22% of mature and 74% of young cattle.
According to veterinary standards, any product that fails to reduce fecal egg counts (FECR) by at least 90% is considered ineffective. In this study, macrocyclic lactones fell short—averaging only 74.5% FECR in adults and 61.6% in young cattle. In contrast, benzimidazoles and combinations exceeded the 90% threshold.
Even when administered as injectables, macrocyclic lactones showed just 68% FECR, slightly better than pour-ons at 63.9%. Cooperia appeared especially resistant, reinforcing the need for updated strategies.
This study highlights that many beef operations may not be achieving effective parasite control. Farmers are encouraged to work with veterinarians to create targeted parasite management plans that include fecal testing.
Ongoing monitoring and product rotation can help improve treatment success and maintain herd health.
Reassessing deworming methods could lead to healthier cattle and improved productivity, especially as parasite resistance becomes a growing concern in livestock management.
Photo Credit: istock-emholk
Categories: Ohio, Education, Livestock, Beef Cattle