Which term describes characteristics associated with dogs?

The term that best describes characteristics associated with dogs is "canine." This term refers specifically to the family Canidae, which includes dogs, wolves, and other dog-like mammals. When discussing traits, behaviors, and diseases pertinent to dogs, "canine" is the appropriate descriptor.

The other terms apply to different groups of animals. "K9" is a colloquial term often used in law enforcement or military contexts to refer to police dogs, but it is not a scientific or comprehensive term for the species or its characteristics. "Feline" pertains to cats and their related species, while "equine" refers to horses and is used for all things associated with horses. Therefore, "canine" is the most accurate term when discussing aspects specifically related to dogs.