I am studying to become an expert in Veterinary medicine
Oh that is cool, the word had been a better place for animals. You will have to deal with their prevention, diagnosis and treatment of disease
I see, can you tell me more about this?
Of course. It is a field of a wide scope. And it covers all animal species, both domesticated and wild, with a wide range of conditions which can affect different species.
Do you know if this field covers the treatment of domesticated dogs?
Of course yes. They help to maintain  food supply through livestock health monitoring and treatment, and mental health by keeping pets healthy and long living.
That is why its my passion, when did this field of medicine originate? 
It could have been in existence right from the beginning of medicine itself and it is  widely practiced, both with and without professional supervision.