I start feeding this supplement every spring just before fly season starts. It really helps cut down on the fly population. It passes through the digestive tract and into the manure to keep fly larva from thriving. Unfortunately, it does nothing about biting insects. There are fewer flies to irritate the horse and I so it is well worth the money.

Pros: effective, easy to feed, horse thinks it's a treat

Cons: a little pricey

This stuff really works! We've fed it for the last 4 years with our horses and have not had any problems and it worked very well to keep the fly population to a minimum. ALL horses in the area do need to be this product for it to work well. It also doesn't work against the big biting horse flies in our are as they don't lay their eggs in horse manure.

Pros: Safe, effective, affordable

Cons: NONE!

This products works really well! I've used it on my two horses for 2 years now! Dramatically cuts down on fly population. But you have to remember flies come from other sources than just horse poop....like dog poop and dead animals....if you sprinkle this on top of your dogs or cats poop it will help that also!

Pros: Works very well!

Cons: Not all flies are killed

I worked as a volunteer at a Ranch that was using this product. It worked great because all the horses at the facility were getting it. It will not work as well in a public facility were some horses are on it and some are not.

Pros: Easy to Use

Cons: Only works if everyone is using it.