Why Cats and Cow's Milk Don't Mix

Did you know that most cats are lactose intolerant? It’s true. While they’ll happily lap up the white stuff if you present it to them, for most cats this “treat” will result in stomach cramps and more, and that’s no fun (for your cat or for you). 

An article in Science Focus debunks the popular myth of the kitty with the saucer of milk: “like all infant mammals, kittens are born able to digest the main sugar in milk, lactose. This sugar is a very valuable source of energy for young animals, but soon after they are weaned, the enzyme that enables them to digest it, lactase, begins to disappear from the gut. When an adult cat drinks milk, the indigestible lactose in its gut may start to ferment, causing a stomach upset."

In fact, lactose intolerance is the genetic default for most mammals and, thus, is perfectly normal in both humans and cats as they age. 

According to Linda P. Case, author of The Cat: Its Behavior, Nutrition, and Health…. "as we grow up, it’s normal for people and cats to begin producing less lactase. Less lactase means less ability to digest lactose. The result may eventually be lactose intolerance." (Source) Symptoms of lactose intolerance include upset stomach, diarrhea, and vomiting. If your cat is lactose intolerant (and almost all of them are to some degree), you'll know within 8-12 hours because they'll start exhibiting symptoms. 

Another very important thing to remember - especially with kitten season starting soon! - is that baby cats are NOT baby cows. Cow's milk doesn't have the correct nutrient balance for baby cats, so if you have a kitten that needs to be bottle fed, be sure to get a kitten milk replacement! 

Cats Really Can't Drink Milk? 

While the majority of cats are lactose intolerant, there are those who continue to produce lactase through life (though in small amounts). Those cats are able to digest some milk with few ill effects. If yours is one of those kitties, then you can give milk as an occasional treat. However, because cats don't naturally drink milk after about 10-12 weeks of age, there are other, more nutritionally appropriate treats that you can give instead - e.g., fish, chicken or other store-bought cat treats. Additionally, even if your cat can drink milk, it's very high in calories. Be sure to give it in very small amounts (like any treat), if you give it at all - or get specially formulated cat milk, so you don't have to worry about whether Kitty can digest it.


Are you surprised by that most cats are lactose intolerant?  It's always a good idea discuss your pet's diet with your veterinarian to make sure you're not inadvertently feeding your cat something that can make him/her sick. If you have questions about the best food and treats to give you kitty or your furry friend is having digestive issues, give us a call or fill out our form to make an appointment with a veterinarian!



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