Officials say that while cattle producers and veterinarians have been able to use highly effective internal parasite control products for many years, but they stress that they may not be sustainable options in the future.
Frequent, long-term use of deworming products can lead to resistant parasite populations, meaning those parasites are no longer killed by the dewormer.
Officials say anthelmintic resistance in cattle parasites has been slower to develop, and they also tend to receive less attention. They say the primary effect of the parasites is decreased production, which is usually difficult to recognize.
Although it is hard to see, anthelmintic resistance in cattle parasites has been documented in cattle from most of the United States. The only way to truly determine the presence of resistance in parasites is to test for it.
Officials with the OSU Center for Veterinary Health Sciences stress that the most effective way to detect resistance is called the Fecal Egg County Reduction Test.
Most veterinarians can perform the fecal egg counts or the samples can be sent to the Oklahoma Animal Disease Diagnostic Lab. A general recommendation is to test at least 20 randomly selected animals or the entire group if it’s fewer than 20 animals.
If resistance is detected, a variety of steps can be taken.
Cattle producers are encouraged to discuss testing for resistance with their veterinarian and to work with their veterinarian to develop parasite control strategies in the future.
