The Truth About Dairy Products and Pets

By PetMD Editorial on Jun. 12, 2017

By Diana Bocco

Confused about sharing dairy products with your furry friends? You're not the only one. And there is some reason for concern; lactose intolerance can cause plenty of tummy trouble for pets.

Dr. Ishpreet Gill, DVM, with Fletcher's Creek Animal Hospital, says that although both dogs and cats can be lactose intolerant, cats are more likely to experience problems. On the other hand, while dairy intolerance is common in adult dogs, it doesn't happen in every dog.

“Some dogs retain the ability to digest milk all throughout their lives,” says Gill. “My own dog, Zorro, loves milk, and I usually give it to him because it does not cause him any problems at all, but this is not true for all dogs.”

To avoid major issues, Gill recommends talking to your veterinarian before giving your dog milk (or any dairy products), and paying attention to any sign of gastrointestinal trouble after your dog consumes even the smallest amount of dairy. “If you give ice cream to Fluffy or Fido and they develop diarrhea, you can be reasonably sure what caused it,” says Gill.

What Makes Milk Such a Problem for Pets?

When young pets nurse, their bodies produce high levels of an enzyme called lactase, which breaks down the lactose sugars found in their mother’s milk, according to Dr. Tawnia Shaw, DVM, who runs The Happy Pet Vet, a mobile veterinary clinic. As pets get older, however, their bodies produce less and less lactase, making it difficult for them to digest any type of milk.

“Since they are unable to break down the lactose in dairy products, this leaves the lactose sugar in their system for the bacteria in their intestines to ferment,” Shaw says. “The fermented bacteria are what give our pets intestinal cramps and diarrhea.”

When it comes to dairy and tummy trouble, however, not all products are the same. That's because the amount of lactose varies from dairy product to dairy products. “Regular milk has the highest amount of lactose, while some milk by-products have less lactose than milk,” says Gill.

Goat Milk Versus Cow Milk: Which is Better?

Pets often have an easier time digesting goat milk than they do cow milk. “Goat milk is easier to digest because it has a smaller, softer casein curd, along with smaller size fat globules, so it is more completely digested in the small bowel, leaving less residue to ferment in the large bowel, which is the cause of the gas,” says Dr. Judy Morgan, DVM, a veterinarian certified in food therapy, acupuncture, and chiropractic care.

The same is true of raw, unpasteurized milk and fermented dairy products, from both goats and cows. “Fermented dairy products are more likely to have the lactose broken down during the fermentation process and be more tolerated,” says Shaw. “This means pasteurized milk that has had the enzymes denatured but still has lactose sugars are more likely to cause problems than raw or fermented milks or fermented cheeses.”

In certain cases, and prescribed by a veterinarian, fermented goat milk can even be used medicinally, said Morgan. “Goat milk contains more small- and medium-chain fatty acids, which are easier to digest than the long-chain fatty acids.” In fact, Morgan points out, fermented goat milk is actually a complete diet, containing the complete array of amino acids, vitamins, and minerals in the proper proportions to sustain life. “I have used this for pets with IBD (inflammatory bowel disease) as a stand-alone diet to allow the gut to heal,” Morgan says.

If you suspect your dog suffers from IBD, consult with a veterinary nutritionist to see what your options are before trying goat milk on your own, since there may be a serious underlying disease or intestinal infection that needs to be treated first.

Clearing Up Myths: Does Milk Cause Worms?

While there are many myths regarding dairy, a common one appears to be that drinking milk causes worms. “I have seen this question posted on the internet and clients have asked it more often than you'd think in our clinic,” says Gill. “To be clear, there is no truth in the claim that milk causes worms in cats.”

Gill doesn't know where the myth comes from, but he suspects it originated because many kittens and puppies are infested with worms, which can be a big shock for pet owners when they bring home their new pet kids.

“Kittens and puppies can get worms from drinking their mother’s milk when Mom is contaminated with worm larvae from not being de-wormed prior to the pregnancy,” Gill says.

Can Dogs Have Yogurt?

Another myth you hear from time to time is that yogurt is good for your pet’s health. “Yogurt in small amounts for a treat can be fine but should not be used to provide probiotic bacteria or calcium to balance a diet because they are not high enough in those ingredients,” Morgan points out. So, while letting your dog have a taste of your yogurt isn't a terrible thing, the idea that it's providing your pet with tons of nutrition is just a myth.

The Other Dairy Treats: Is Cheese and Ice Cream Okay for Pets?

While some types of dairy are likely to cause tummy trouble, some products are OK to use as an occasional treat.

For example, many people use a small piece of cheese to hide pills to get their pets to swallow them, and this is perfectly fine except for a few exceptions, says Shaw. “Some medicines do not do well if taken with high calcium foods,” she said. “Doxycycline, an antibiotic, for example, gets bound to the calcium and then does not get absorbed.”

To make sure you can use dairy products, always read the packet insert or ask your veterinarian if the medicine being prescribed can be given with cheese or dairy products.

Ice cream is another example. A small amount of ice cream is perfectly fine as casual dog treats or cat treats, but don't make it a habit. “Personally, I think ice cream is a very poor choice of treats, but that doesn't mean I haven't ever let one of my pets lick the bottom of the bowl,” says Morgan.

An important word of caution before sharing any treats with your pet: “Definitely avoid all sugar free options,” says Shaw. “Many sweeteners, like xylitol, are toxic to our pets and can cause life threatening drops in blood sugar.”

Other things to watch out for when giving your pet ice cream are macadamia or hazelnuts, and chocolate, as both can be toxic to cats and dogs.

This article was verified and edited for accuracy by Dr. Katie Grzyb, DVM