Deworming Recommendations
The standard practice of deworming every 2 months has been followed for more than 40 years, but much has changed in that amount of time. Parasite drug resistance has increased and at a rate that is faster than the development of new dewormers. A more selective deworming approach is therefore recommended to help decrease parasite resistance. In order to select the proper deworming medication and frequency, a fecal egg count is performed to determine the parasite load the horse is currently carrying. Parasite infection varies with age and health of the horse. Therefore, it is important to perform fecal egg counts routinely throughout the horse’s life.
For horses in the low shedder category (0-200 eggs per gram):
-Deworm only twice a year rotating between dewormers:
-Spring: ivermectin (Equell) or moxidectin (Qwest)
-Fall: Ivermectin +praziquantal (Equimax) or moxidectin+praziquantal (Qwest Plus).
For horses in the medium shedder category (200-500 eggs per gram):
-Deworm twice a year as above unless advised differently
For horses in the high shedder category (>500 eggs per gram):
-Deworm four times a year rotating between dewormers:
-Spring: ivermectin (Equell) or moxidectin (Qwest)
-Summer: fenbendazole (Panacur), oxibendazole, pyrantel (Strongid)
-Fall: Ivermectin +praziquantal (Equimax) or moxidectin+praziquantal (Qwest Plus).
-Winter: fenbendazole (Panacur), oxibendazole, pyrantel (Strongid)
If a fecal egg count is negative for parasites, it is still important to deworm twice a year as not all parasites are identified with a routine fecal float (bots and tapeworms). The ideal time to submit a fecal sample for testing is in the spring or fall, at a minimum of 8 weeks since the last deworming. Daily dewormers are not recommended due to the possibility of promoting parasite resistance.