An old profession.
The vet comes from the Latin word veterinarius ie ars veterinary practitioner, a kind of medical practice in sick animals. Originating in vetus (old), veterinus would appoint specialist pack animals of a certain age, especially equine (donkey, horse, mule). In Spanish there is also a farrier term of Arab origin, to refer to the vet.
The domestication of animals brought in not only their use but their care and the prevention and cure of their diseases. Thus was born the vet, which initially involved the application of remedies, and later became a science. The vet is a profession that has accompanied man since antiquity.
The word profession comes from the Latin professio-onis meaning action profess effect, the common use of the concept has different acceptances including: employment, college or trade that each has and shall publicly protesting something or public confession (confession of faith of a typo, politics, etc.).