Cow's milk is comprised of water, fats, carbohydrates, proteins, vitamins, minerals and enzymes. The majority of milk, 87 percent, is water. The carbohydrates of milk are present in the form of lactose, comprising 4.9 percent of the product.
Milk has a pH balance of approximately 6.5, making it mildly acidic. A pH balance of 7.0 is usually considered neutral, while a pH balance higher than that is often labeled basic.
Milk is not good for dogs. Once dogs are weaned, their bodies cannot properly digest milk. Drinking milk can upset dogs' digestive tracts and give them diarrhea.
All milk contains sugar. Milk from most mammals contains lactose, a sugar composed of glucose and galactose molecules. This sugar is not as sweet as other disaccharides and is generally found in low quantities in cow's milk (about 5 percent).
Milk can be difficult to digest for some or most dogs. While it is not actually "bad" for them, their tolerance for milk is determined by their own body chemistry and its tolerance for lactose.
Milk is a specific type of homogeneous mixture called a colloid. Examples of other commonly encountered colloids include prepared gelatin and fog. The particles in a colloid are large enough to see in direct light, but smaller than those found in a suspension.
Dairy farming seems to have been invented in Central Europe around 8,000 years ago. Many people in Europe have used sheep and goat milk since then to make cheese and yogurt. Most adult humans worldwide cannot drink fresh milk without getting sick.