All provinces have their own way of coding. The letters represent the vet's office and the numbers represent the year the cat was spayed/neutured. At least that is how it works in Alberta. My cat had an Alberta Tattoo but got lost in Ontario so you may run into the problem of not being able to match the tattoo unless you are curious enough to go into another province. I remember calling my vet in Alberta 2x a month hoping that someone in Ontario would have figured it out...but no..never found her
