Allicin, the bug-repelling ingredient in raw garlic, can lead to Heinz Body anemia when your horse eats it. that's a disease that destroys your horse's red blood cells. Most horses like the taste of garlic, and they're happy to consume it. And anecdotal evidence does show it repels flies. But at what cost' Reduced red blood cells can lead to exercise intolerance and reduced immunity to disease.
?Nutrition Editor Dr. Juliet Getty