When should i start feeding garlic powder to my horse?

I have a garlic powder that i want to give my horse as fly control. When should i start putting it in his feed?When should i start feeding garlic powder to my horse?
Garlic as a feed is worthless to repell flies, and the toxicology of garlic to horses is still being researched. We already know that it produces anemia, but what amount fed in each individual horse before the anemia develops is still uncertain. So, it is an ineffective fly repellant, and is toxic at undetermined levels......I would find another way to deal with the flies. Here is an article you should read...............





http://www.equisearch.com/horses_care/fe鈥?/a>When should i start feeding garlic powder to my horse?
This is one of the horse Myths. Garlic does not help in fly control. People think it does, but studies have shown that it doesn't. You are just wasting time and money feeding your horse garlic powder to control flies. Non of the so called natural remedies work.
Give it a few weeks to work in but there are other natural options I just tried this marigolds spray it works and if you plant marigolds around the barn if helps with flys.
At least a few weeks before the bugs come out so it gives time to start working.
2-3 weeks before the nasty bug season starts.