In Massage Therapy news, there was a discussion on the benefits of massage for horses.
Make sure that the therapist is a trained professional. They should take a specialized program and is a graduate of an accredited school:
International Association of Animal Massage and Bodywork / Association of Canine Water Therapy (IAAMB/ACWT)
EquineRehab.ca

One of the main benefits of massage for horses is prevention, as the therapist will find and fix small problems before they become big, and the rider starts to notice performance problems.
Horses are also great at compensating and it’s important to treat the cause, not just the symptoms.
Massage is really a workout for the muscles. If it’s too heavy, the horse is tensing up. Too light and the horse thinks you are a fly.
Massage therapy does not replace vet care but works in conjunction with routine vet care.
The benefits of massage for horses, is similar to massage for people –prevention, and maintenance.

Personally I don’t treat horses, not because I don’t have the strength (which I do!) but because I’m allergic to hay and would spend more time sneezing than actually working!