Q: I have a 12-year-old gelding on a regular deworming program (I rotate ivermectin, pyrantel pamoate, fenbendazole, and praziquantel/ivermectin) and he’s very healthy*. Is there any problem with exercising him on the same day that I deworm? Should he get some time off after deworming?
If your horse had not been dewormed in a long time, particularly if he were quite young, there would be a slight risk of colic after deworming due to a heavy parasite load being expelled. In that scenario, it might be advisable to give the horse that day off after deworming, or consider a half dose of a fenbendazole product, to avoid killing large numbers of ascarid parasites at once. This half dose would then ideally be followed up within several days with an ivermectin or moxidectin dewormer.
*Editor’s Note: Since this article was originally published, a standard rotation is no longer recommended. Read more about current deworming science here.
Julia H. Wilson, DVM, Diplomate, ACVIM, associate professor & division head, Large Animal Medicine, Veterinary Population Medicine, College of Veterinary Medicine, University of Minnesota.
good info
I have wondered if one had an animal that was of an unknown parasitic status, if a half dose would be better. Thx!
You should make it much clearer that this answer is out of date instead of just some tiny footnote. You should only poison your horse when the benefit outweighs the cost.