I love the MTG too. As with any product do a spot test first to make sure your horses don't have a reaction to it.
It smells like when you have been standing by a wood fire all day what your clothes smell like. So yeah if you want your horse to smell purdy don't try it.
"Until one has loved an animal, part of one's soul remains unawakened..."
- Anatole France
I looked at this, and I was going to answer before I saw anyone's answer and I thought that I would be the only one to mention MTG and sadly I'm not, but i recommend MTG it works on everything hair related.
"Doing what you like is freedom, liking what you do is happiness."