(ivermectin 1.87% Paste). Equine parasites can cause a wide range of health problems for all horses, regardless of breed, age or stabling environment. Fortunately, parasite control products, or dewormers, are available which safely and effectively protect horses from damage caused by parasites. ZIMECTERIN has been the #1 choice of horse owners for nearly 20 years. ZIMECTERIN controls a broad spectrum of worms and bots, provides a wide margin of safety, and is highly effective for protecting all horses including foals, breeding mares and stallions.