Milk is probably one of the worst things you can give your cat. Most cats are lactose intolerant so it gives them a heck of a stomach ache, along with GI problems and the runs. Why do they still drink it you may ask? They can’t make the connection between the milk and why they get sick, of course.
Hmmm...in all the 18 years of her life, she’s never gotten sick from drinking it.
I don’t think it’s anywhere near “most” cats that are lactose intolerant. The majority of cats I’ve had liked milk and had no digestive upset from it. One finished the milk from a human’s cereal bowl *every* morning for years (and sometimes got lucky when more than one human had cereal with milk for breakfast).
Whiskas makes a product called Catmilk.
It comes in boxes that are similar to juice boxes.
Petsmart carries it, and sometimes Walmart.
It’s very good for kittens, and adult cats, too.