Our 6 month old Siamese cross (will be neutered in September) pants heavily, like a dog, after minimal exercise. I had him at the vet last night for vaccinations & exam but I completely forgot to mention the panting (because I am a horrible and forgetful Cat Mom apparently). I will bring it up in a few weeks when we take him in for the neuter, but I thought I'd mention it here, in case anyone has had a similar experience?