A horse trainer is responsible for training, behavior and overseeing the exercise routine of each animal in their charge. In larger stables they may work with a barn manager or foreman (and where applicable, oversee an assistant trainer) to establish working schedules which will be carried out by grooms and exercise riders. At smaller locations the trainer may do the prepping, riding and groundwork themselves.
Generally a trainer must have previous professional experience with horses, whether it is previous training, a proven track record (so to speak) or professional competing. A high school diploma is almost invariably required and any formal schooling in veterinary science or animal husbandry is always helpful.
Developing & implementing specific exercise routines
Developing supplement schedules
Under saddle work
Training in general manners
Correcting behavioral issues
Managing stable/ barn employees