Adult dogs are generally lactose intolerant, meaning their systems cannot handle dairy products. This is because they do not produce an enzyme called lactase, which is necessary to break down the lactose that is present in dairy products such as milk and cheese.
Lactose intolerant pets may be able to tolerate other dairy products such as cheese (including cottage cheese) or unpasteurized yogurt because the lactose has been removed or partially broken down by bacterial processes.
Most dairy products, however, are likely to cause digestive upset such as diarrhea (from milk or ice cream) or constipation (from cheese). Dogs don't need to eat dairy products because they get sufficient calcium and protein, the major nutrients provided by dairy products, in their dog food, provided you are feeding a high quality commercial food.
Many dogs are also allergic to dairy products. After feeding your dog milk, ice cream, or cheese, you may notice him licking his paws (because allergic reactions in dogs cause itchy feet), or rubbing his face against furniture or the floor (his face will itch, too). Those are common symptoms of allergies in dogs. You may notice nasal or eye discharge, but those are less common.
Puppies are not necessarily lactose intolerant (they are able to tolerate milk from their mother, after all), but they are often allergic to cow's milk. They do not tolerate it well and it can cause digestive upset and frequently causes diarrhea. It will often cause them to have "accidents" in the house because they are not able to wait to go outside. Also, excess calcium from milk can have a harmful effect as it can interfere with normal bone growth.
Too much cheese causes the opposite problem. It can cause constipation in dogs, as well as allergic reactions. Symptoms of constipation include straining to have bowel movements, smaller than normal feces, and hard, dry feces.
Despite their lack of tolerance for them, dogs usually really like dairy products like ice cream and cheese. These can be given in small amounts as a treat, as long as they are not used on a regular basis and your dog is able to tolerate them in small amounts. Small bits of string cheese work well as a reward during dog obedience training.
Some dairy products can actually be beneficial to dogs. Plain yogurt, in small amounts, can aid the digestion. It can be added to your dog's food or fed separately. The key here is moderation. Too much yogurt will likely result in diarrhea. Stick with a few spoonfuls.
Dietary Supplements for Constipation Dog Cheese
Dogs that are getting exercise, eat a good diet and have the opportunity to defecate three times a day rarely get constipation. If they do, a dietary supplement that contains fiber such as PetAlive Natural Moves is made to help with healthy digestion and treatment of constipation.
How to Treat Allergy in Ten Easy Steps
Hnilica, K. A.