I have been feeding my polo and dressage horses for some time with gelatine and noticed that they all benefited. There was less stiffness and somewhat faster recovery from exercise.
With my older horses, one Cleveland Bay mare, 25 years old and my 16 year old Warmblood it certainly seemed to help with arthritic issues. However, I recently ran out of the gelatine and decided to see what affect it would have.
My Cleveland Bay become noticeably stiffer in all her leg joints and my Warmblood showed signs of slight lameness in the front near side.
I will now order some more gelatine and they will stay on it!