Bug Zap Garlic for horses is a natural insect repellent that helps to repell flies and mosquitoes. Deters breeding of insects in the manure. Garlic: A natural source of sulphur to help keep flies and mosquitoes away. Helps with digestion and circulation. Diatomaceous Earth: Helps to prevent breeding of larva in the manure. Helps to control internal and external parasites. Apple Cider Vinegar: Helps to improve circulation. Balances the horse PH thus helping to defer colic. Stimulates proper digestion. Assists in helping to control internal and external parasites. Flaxseed Oil: High in Omega-3 fatty acids. Promotes a healthy, glossy coat and boost the immune system. Supports good blood circulation.