When Iams pet food had a commercial with a cat saying he couldn't read, I mocked it. He says so in a way that almost suggests that he can't read because he's an Iams cat; but of course that's nonsense because cats can't read.

Now they're advertising dog food. While the Iams cat can't read, the Iams dog can't count. I mock it, because he says so in a way that suggests that it's the Iams that stops him being able to count...

Thing is, I suspect that dogs can count. I don't know how to prove it practically, but consider the following:

Dogs are pack animals; I think it's safe to say they still exhibit some of that behaviour when they live in groups. One of the main purposes of a pack of carnivores is to hunt, and hunting requires an ability to pick targets: to decide how strong they are, whether they are enough food, and so on. I propose that any judgement involving variables like 'how strong is my pack' and 'how much food does it need' requires the ability to appreciate how large one's pack is, particularly the ability to compare the numbers of [healthy] members it has.

You could argue that a practical understanding or appreciation of the natural numbers isn't sufficient for 'counting', but I think that's a daft argument. If your definition of counting includes 'speaking the natural numbers in order' but not 'using my appreciation of the ordering of the natural numbers to quantify the strength of my pack' then it seems artificial and lacking in value, not to mention unreasonably anthropic.
You'll pardon me if I don't subscribe to it.

So yes, going back to the original topic: Don't feed your dog Iams. The manufacturers appear to admit that 'Iams dogs' are lacking in primal mental faculties.