When I offer freshly milked milk to someone who has only known dead milk from the supermarket, they usually show lots of enthousiasm.
Milk can be considered a superfood, it contains almost everything the body needs.
Milk production is generally connected with the production of meat. Who believes it possible to produce milk without producing meat, should do it in practice before criticizing from a purely theoretical point of view a moderate meat consumption.
Fresh, recently milked milk contains enzymes that support their digestion, which however are destroyed when heated. During the hours the bacteria (usually probiotic ones) in the milk multiply themselves, they also support the digestion, and in room temperature they turn the milk sour and make it curdle within one or two days. Both the fresh milk and the sour milk are worthy foods. (If milk gets sour in the fridge, however, it is not that healthy.)
In order to resorb the milk's calcium, it's best to take sour milk since the acid supports the calcium resorption.
The preservation of live milk is difficult. Frequently it is pasteurized or sterilized, sometimes moreover homogenized, and so it loses its physiological properties. The best method to preserve milk (although only that of ruminants) is to make cheese out of it.
Fresh milk serves to prepare good dishes like muesli (with flaked oats and fruits), ice-cream or cocoa. Also yoghurt and butter can be made out of it.
If we drink tea for its tannins anand their astringent effects, we do not add milk for it links with the tannins and reduces their effects. But if we drink tea or coffee for their caffein, we can reinforce the effect by adding milk because by combining with the tannins it sets the caffein free. Milk inhibits the iron apsorption. Therefore it is recommendable not to use it in the same meals as meat not blend it with teas like that of stinging nettle.
Of course there are differences if the milk is from a goat, cow, ewe, camel, mare, donkey ... The milk of ruminants and camelids contains quite a lot of casein and so can be used for making cheese.
Some people state that milk deprives the body of calcium. It's quite an absurd idea that the female mammals put a lot of calcium in a food for their offspring and that moreover that food deprives the baby's body of calcium. If it were thus, the mammals would not be that successful in the evolution. The experiments which show that, no doubt, were made with dead milk by people who do not know live milk with emzymes and bacteria.
For many people it is of course of little relevance to know that raw milk apports calcium to the body because they just cannot get it. Still it is not necessary to dispense of all dairy products and live an ascetic vegan life for products like yoghurt and cheese are ussually accessible.
Some people have a lactose intolerance and have to avoid milk, mainly indigenous populations of the Americas and East Asia. That's why the macrobiotic, based on East Asian teachings, discourages the consumption of milk. This however is not relevant for people who can digest lactose, everyone has to know it themselves.
Janzing, Gereon: Ziegenhaltung und Milchverarbeitung. In: Kritische Ökologie 80, Sommer 2013: 15-20.
Milk in the ABC of Medicinal Plants (in Spanish)