I'm a retired cop. I retired as Lieutenant over road patrol and part of my duties was to over see the daily operations of the patrol division as well as property/evidence, disptach/communications, crime watch programs, special events and yes, the canine unit as well as horse/mounted patrol. I wore many hats over the years from dispatcher, crime scene investigator, criminal investigator, acting chief on numerous occasions and so on.
I hated the mounted patrol unit, great for public relations, but a nightmare to manage. But I LOVED the canine patrol. That was a very productive unit from narcotics to tracking & apprehension.
OK, first off, get yourself a minimum of an ascociates degree in criminal justice, then search out a local law enforcement agency to sponsor you through a police acadamy.
Secondly, the EASIEST way to get into any canine division is to purchase your own dog, and then go to canine school with it ON YOUR OWN. This will cost you better than $1000.00 for the dog and another $1000-$2000.00 for the training. This alone will be monumental in getting a job with any agency as an officer and also as a canine handler. Why you ask, because this saves the department THOUSANDS of dollars that they don't have to ask the city council or the county commissioners for. You have to realize that most canines only last for a period of 5-6 years on the beat before they are retired and once retired they usually wind up being given to their handlers to care for.
I wish you well in choosing which ever field you wish to pursue, but law enforcement is a noble field and canine patrol is one of the elite.
Mike