Equine De-worming
Historically, horses have been given de-worming medications at regular intervals. This process has lead to the eradication of the large strongyle parasite, but has also lead to the development of drug resistance of some parasites as well as the selection of the small strongyles, particularly the variety that encyst in the gut wall of the horse.
Because the small strongyles are now the most prevalent form of parasites in the adult horse, it is imperative that medications that kill the encysted forms of these parasites be utilized. Below are the only medications known to kill encysted forms and their efficacy in doing so:
Ivermectin – 30% effective
Quest – 100% effective
Panacure PowerPack – 100% effective (as long as no resistance has been acquired by parasites in your area)
Also, because parasites are starting to build up resistance to many of our drugs, it is best that we now stop de-worming haphazardly and start using Equine Parasite Analysis (fecal egg tests) to determine how often each horse should be de-wormed. After this has been done, a strategic de-worming schedule can be created so that the horse is not under OR over-medicated and additional drug-resistance is not produced.