topShould I be concerned with parasite resistance?
Parasites that are resistant to a product’s active ingredient make it less effective than it once was. When confronted by rows of dewormers, many horse owners can be confused about their choices, and the issue of equine parasite resistance adds even greater confusion. Even though there are dozens of brand names on the shelf, there are only three major chemical classes of equine dewormers. Widespread resistance has been demonstrated in small strongyles (one large group of parasites) to benzimidazoles, which belong to one of the older classes of dewormer.1,2 Additional research showed 40.5 percent of farms had small strongyles that were resistant to pyrantel, a second chemical class of dewormer.1 The third class of dewormers is macrocyclic lactones, containing products like ivermectin and moxidectin. Large-scale studies show ZIMECTERIN Brand Products, with the active ingredient ivermectin, are effective against small strongyles.1,2,3 See study results below. Concerns have been raised abo
