Don't Give Milk to Cats
Contrary to the popular thought that cats love milk—and most do like the taste—it typically is not good for them. Most cats can't digest milk properly because it contains lactose (milk sugar), which may cause diarrhea.
Since cats that consume completely balanced commercial diet don't require any of the nutrients in milk, there is normally no reason to give it.
If your cat can't drink milk without developing digestive disturbances, but he or she keeps asking for it, there are some products made specifically for cats that won't upset their stomach. This specially formulated “milk” is available in pet stores.
Because milk is a food and not just a drink, it's a good idea to reduce the amount of solid rations you feed your pet if you do serve a special cat milk.
Can My Dog Have Ice Cream or Milk?
Dogs love ice cream, but don’t have the proper enzymes to properly break down the sugar in milk or ice cream. Most dogs lose the ability to digest lactose shortly after weaning.
This advice might seem contradictory if your vet suggests hiding pills inside a slice of cheese. However, most cheeses contain very little lactose, only about a gram per serving. Compare that to whole milk at eleven grams, and you’ll see why milk or ice cream can upset your pet’s stomach.
If your pet enjoys and appears to tolerate these dairy products, you can give small amounts. Better yet, give your pet one of the special dog milks with the lactose removed.