What's really surprising is that he didn't get bucked in the face. Seriously, I own 4 horses and if they don't want you bothering them they will make it known. They will swat you away, kick, buck, head-butt, they're large and powerful animals. Even washing them, you have to be careful.

Now, aside from the fact that this is against nature and most major religion, chemically and medically it is dangerous to mix sexual fluids from two species. It can lead to a very high risk of penile cancer in some cases! And I think we all know how AIDS got started...