Veterinarian or Veterinary Technician top the list of careers with horses. But you would have to make a commitment to attend university for a number of years to earn a degree and be able to practice. Some other careers include farrier (taking care of horses' hooves), riding instructor, exercising horses, Mounted Police, jockey, grooming horses, boarding horses (involves having a barn and grazing land as well as seeing to the horses' needs), training horses, breeding horses. Hope this helps.
