A Doctor Who treats children is called a paediatrician
A doctor who treats animals is called a Veterinarian or a Veterinary Doctor
Doctor
That would be a pediatrician.
A doctor - or a podiatrist.
A Doctor who treats animal diseases and injuries is a veterinary surgeon (British English) - or Vet for short.
they are called either a therapist or a psyciatrist
A doctor who treats the elderly (technically defined as any person over the age of 65) is a Geriatrician, or Gerontologist.
neurologist specializing in memory disorders
A 'horse doctor' is called a Equine Veterinarian.
A mixed animal doctor is a veterinarian who treats large animals (cows, sheep, goats, pigs, llamas, alpacas), small animals (dogs, cats, etc.) and horses.
Too many sugary treats can cause cavities in horses. A few is OK though, and most treats designed for horses are made with minimal sugar to prevent cavities.