Never worked at petsmart, but I did get a doggy day care job - unfortunately I'm pretty sure I only got that job because I had a really strong recommendation and grooming experience, which meant I could cover for bathers.
They'll probably care more about things like your ability to be on time, reliable, flexible, responsible, etc. and follow directions and safety procedures than they'll actually care about your experience - but saying you've worked with dogs before and are knowledgable about their body language and way they communicate and can quickly identify when one is fearful, stressed, or threatening other dogs will probably help.
They'll probably ask you typical questions like "why are you a good candidate for this job?" and "why do you want this job?" and "what do you expect working with live animals to be like?"