I just found out my horse has white line disease. I guess the owners before us(we got him a few weeks ago) didn't check his feet. Well, we had the farrier take his shoes off and trim him. He said he got it out, but poor old Boston being 23 has cracks and needs medication. Anyways, how long do I need to spray the medication on? He's trimmed once every two months. How do I get rid of the cracks in his feet? Are horses able to be rode with it? Will he get laminitis? I feel sorry for the poor guy. Sorry for all the questions I just found out what it was. Thanks.