How can I get my two year old lab and my 8 year old horse to get along?

I have a two year old lab, and buying an 8 year old mare throughbred mix. I want to train them both to get along so that my lab (Gigi) can go on the trail with me and my horse (Morgan. Gigi has never been around horses before, and Morgan I am buying from a trail riding/ lessons barn. So does anyone know of a way to get Gigi to the point where she won't bark or chase Morgan, and Morgan to the point where she won't be frightened of my dog?

If you have a round pen or some sort of paddock or corral, try pinning your dog up on one side of it, and your horse on the other. Have a fence between them so the horse doesn't trample the dog. Give them about 15 min a day like that then let them go. Eventually it won't bother them at all and you can work from there.

i have a dog that when we got him he liked to bite on the horses tails. he got over it because he was kicked. you certaintley don't want your dog to be kicked. my dog wasn't hurt, it just knocked some sense into him. teach him the word no and everytime does what you ask, reward him. it you tell him no when he messing with your horse he will soon learn that he is not allowed to mess with the horse.