Scratches?

[JUDYK89@aol.com]

I was wondering if anyone knows...

My mare has black crusty stuff that "grows" on the front of her rear legs, my vet called it "stud crud" (I believe it's from urine soaking and dirt sticking). Would this be the same type of infection as scratches or rain rot?  I've tried a dozen different things to get rid of it, maybe I'll try some of your solutions?  Another vet also recommended, for scratches, Nitrofurazone and antibiotics (don't remember witch antibiotics).  He says it's a new treatment, and it works every time.

Judy