Does anybody know how much for a horse to keep flys under control?

We feed 1 oz per horse once a day, after a two week loading dose of 2 oz per day per horse.

ETA:  We buy from Springtime and have for twenty years.  They carry an excellent, consistant product! 

No more than 2 Oz. Garlic can cause anemia. Buy an actual horse supplement rather than OTC as it’s safer since the allicin has been taken out.