Can Dogs Drink Milk?

It is striking to see how contradictory the opinions are when you go looking for information on whether a dog can drink milk. Some say they not only can but that it is advisable, while others say it is not a good idea.

The truth is that all of them have a point, as long as we are talking about adult dogs, since puppies need more particular care. Let's run through when a dog can drink milk and what precautions we need to take.

What Is Milk?

Milk is a liquid secreted by the mammary glands of mammals to feed their young. Much of the energy it contains comes in the form of a disaccharide called lactose, formed by the joining of two monosaccharides: glucose and galactose.

Drinks extracted from pulses and grains, such as soya, oat or almond, are not considered milk.

Broadly speaking, milk is a mixture of fat and water that does not separate out, but stays stable over time. That stability comes courtesy of certain proteins (caseins) that have one end which interacts with the fat and another which interacts with the water.

So in every case we have:

• Water.
• Carbohydrate.
• Fat.
• Protein.

Within milk, each species has a different composition, since depending on the species the young will have different needs. That said, the milk most widely drunk in human nutrition is the milk of female Bos taurus, or as it is better known, cow's milk.

The specific composition of this milk, once pasteurised or sterilised, in its "whole" form is:

• 88.4% water.
• 3.8% fat.
• 3.06% protein.
• 4.7% carbohydrate.

The nutrient percentages may look small, but if we take out the water we have:

• 32.75% fat.
• 26.37% protein.
• 40.51% carbohydrate.

What is more, the proteins are of enormously high biological value. It has vitamin A, D and E; B complex vitamins and vitamin C.

It is a well-known source of minerals, potassium and calcium chief among them. The latter is also absorbed remarkably well compared with other foods containing more calcium than milk itself, since what matters is not how much of a nutrient there is but how much is absorbed.

Beyond these minerals it also has zinc, iodine, iron, phosphorus, sodium and magnesium.

What Problems Can Giving a Dog Milk Cause?

Lactose intolerance: This is a condition arising from an enzyme shortfall, specifically of lactase (which splits lactose into galactose and glucose) so that it can be absorbed.

The small intestine produces this enzyme during nursing and then stops doing so; even so, thanks to certain mutations many people and some animals carry on producing it.

When lactase production stops, the lactose is not absorbed in the intestine and reaches the large intestine, where certain bacteria can indeed make use of it and multiply beyond their usual concentration, causing diarrhoea, wind and discomfort. What is more, lactose draws in a great deal of water and any other nutrients dissolved in it, so it also affects how those are absorbed.

This is the most common problem from drinking milk and it does not always clear up when the milk is withdrawn, but it is not the only one.

Dairy allergy: This should not be confused with the above, since its symptoms come from the immune system's response and the former's do not. The symptoms can sometimes be similar, but alongside diarrhoea there is itching, reddened skin and ear infections. Respiratory symptoms are less frequent. Although it is a less common problem than the previous one, it is true that dairy products are frequent allergens.

Unlike intolerance, where a sugar was the source of the symptoms, here they come from the milk proteins and the symptoms do clear up once the food is withdrawn.

Can Dogs Drink Milk at All?

The answer is going to depend on the dog. The simplest way to find out is to let them try it, in full knowledge of the risks this can pose to their health.

We certainly do not consider it an advisable practice in the slightest, nor do we suggest that an animal's diet should depend on this food, however nutritious it may be.

Can Puppies Drink Cow's Milk?

This is an entirely reasonable question given what we have set out. The answer is no, and we are going to explain why.

The milk of every species does not have the same composition. This is the composition of dog's milk compared with cow's milk:

Cow's milk Dog's milk 88.4% water 78.6% water 3.8% fat 9% fat 3.06% protein. 8% protein 4.7% carbohydrate 3.1% carbohydrate

Cow's milk has a very different composition from the milk a puppy takes from its mother, and the lactose concentration is higher, so they would not be able to digest it all and would end up with the problems already mentioned.

This is a tremendously sensitive stage in these animals' lives, and diarrhoea can compromise not only their growth but their survival.

What Is the Best Milk for a Dog?

If you want to try it anyway, one option would be lactose-free milk. Its nutritional value is similar to ordinary milk, since it is simply treated with lactase. It keeps the composition of other milks, with the lactose already split.

As for the fat content of the milk (whole, semi-skimmed or skimmed), there is no specific recommendation. Given in small amounts to a healthy dog, they are less likely to cause problems.

As for the brand, there is none more suitable than any other. Under no circumstances should raw milk be given to a dog.

Can a Dog Eat Dairy Products?

The answer depends on the dairy product. Broadly speaking, the more it is fermented, the less lactose it will have, since lactose is the fuel the bacteria need.

In principle they need not be made from lactose-free milk; these will always be safer, but the increased cost of such products is not worth it.

Plain yoghurts and cured or semi-cured cheeses can be safe. To see the effect on our animal, they should always be given in small, increasing doses, with the final amount leaving no symptoms at all.

Another product worth considering would be curd cheese, since it has little lactose. As for dairy allergy, this will occur with every product derived from milk, so a dog with this condition will not be able to eat any dairy at all.