Formal:
* Canine guardian: This emphasizes responsibility and care for the dog.
* Dog handler: This term is often used in the context of competitions or training.
* Dog parent: This implies a close, loving bond with the dog.
Informal:
* Dog person: This describes someone who enjoys dogs and may own one.
* Dog lover: This emphasizes a strong affection for dogs.
* Dog enthusiast: This suggests a passionate interest in dogs.
The best word to use depends on the specific situation and the tone you want to convey.