Milk is an opaque white liquid produced by the mammary glands of mammals. It provides the primary source of nutrition for young mammals before they are able to digest other types of food. The early lactation milk is known as colostrum, and carries the mother's antibodies to the baby. It can reduce the risk of many diseases in the baby. The exact components of raw milk varies by species, but it contains significant amounts of saturated fat, protein and calcium as well as vitamin C. Cow's milk has a pH ranging from 6.4 to 6.8, making it slightly acidic.//
There are two distinct types of milk consumption: a natural source of nutrition for all infant mammals, and a food product for humans of all ages derived from other animals.
In almost all mammals, milk is fed to infants through breastfeeding, either directly or by expressing the milk to be stored and consumed later. Some cultures, historically or currently, continue to use breast milk to feed their children until they are 7 years old.
In many cultures of the world, especially the Western world, humans continue to consume milk beyond infancy, using the milk of other animals (especially cattle, goats and sheep) as a food product. For millennia, cow's milk has been processed into dairy products such as cream, butter, yogurt, kefir, ice cream, and especially the more durable and easily transportable product, cheese. Modern industrial processes produce casein, whey protein, lactose, condensed milk, powdered milk, and many other food-additive and industrial products.
Humans are an exception in the natural world for consuming milk past infancy, despite the fact that more than 75% of adult humans show some degree (some as little as 5%) of lactose intolerance, a characteristic that is more prevalent among individuals of African or Asian descent. The sugar lactose is found only in milk, forsythia flowers, and a few tropical shrubs. The enzyme needed to digest lactose, lactase, reaches its highest levels in the small intestines after birth and then begins a slow decline unless milk is consumed regularly. On the other hand, those groups that do continue to tolerate milk often have exercised great creativity in using the milk of domesticated ungulates, not only of cattle, but also sheep, goats, yaks, water buffalo, horses, and camels. The largest producer and consumer of cattle and buffalo milk in the world is India.Top ten per capita cow's milk consumers (2006) Country Milk (litres) Cheese (kg) Butter (kg) Finland 183.9 19.1 5.3 Sweden 145.5 18.5 1.0 Ireland 129.8 10.5 2.9 Netherlands 122.9 20.4 3.3 Norway 116.7 16.0 4.3 Spain 119.1 9.6 1.0 Switzerland 112.5 22.2 5.6 United Kingdom 111.2 12.2 3.7 Australia 106.3 11.7 3.7 Canada 94.7 12.2 3.3
The term milk is also used for whitish non-animal substitutes such as soy milk, rice milk, almond milk, and coconut milk. Even the regurgitated substance secreted by glands in the mucosa of their upper digestive tract which pigeons feed their young is called crop milk though it bears little resemblance to mammalian milk.
Milk glands are highly specialized sweat glands. It has been suggested that the original function of lactation (milk production) was to keep eggs moist. Much of the argument is based on monotremes (egg-laying mammals):
Animal milk is first known to have been used as human food during the Secondary Products Revolution, around 5000BC. It is assumed that when animals, such as cattle were first domesticated, it was only for purposes of meat. Cow's milk was first used as human food in the Middle East. Goats and sheep are ruminants: mammals adapted to survive on a diet of dry grass, a food source otherwise useless to humans, and one that is easily stockpiled. The animals dairying proved to be a more efficient way of turning uncultivated grasslands into sustenance: the food value of an animal killed for meat can be matched by perhaps one year's worth of milk from the same animal, which will keep producing milk â€” in convenient daily portions â€” for years.
Milk byproducts found inside stone age pottery from Turkey indicate processed milk was consumed in 6500 BC some thousands of years before the ability for adult humans to digest unprocessed milk had evolved.
DNA evidence extracted from Neolithic skeletons indicates that a thousand years later in 5500 BC people in Northern Europe were like all other peoples of the time and were still lactose intolerant. Earthenware vessels found in England from a thousand years after this in 4500 BC contain milk byproducts indicating milk was used in some form although perhaps not drunk directly.
Today lactose tolerance is the key distinguishing feature of Northern European peoples with around 95% of the population displaying the trait compared to around 15% to 20% for people of Middle Eastern descent, 5% amongst Han Chinese and 0% amongst American Indians.
Milk was first delivered in bottles on January 11, 1878. The day is now remembered as Milk Day and is celebrated annually. The town of Harvard, Illinois also celebrates milk in the summer with a festival known as ``Milk Days``. Theirs is a different tradition meant to celebrate dairy farmers in the ``Milk Capital of the World.``
In addition to cattle, the following livestock animals provide milk used by humans for dairy products:Camel Donkey Goat Horse Reindeer Sheep Water buffalo Yak
In Russia and Sweden, small moose dairies also exist.
According to the National Bison Association, American Bison (also called American buffalo) are not milked commercially. However, various sources report cows resulting from cross-breeding bison and domestic cattle are good milk producers, both during the European settlement of North America and during the development of commercial Beefalo in the 1970s and 1980s.
Human milk is not produced or distributed industrially or commercially; however, milk banks exist that allow for the collection of donated human milk and its redistribution to infants who may benefit from human milk for various reasons (premature neonates, babies with allergies or metabolic diseases, etc.).
All other female mammals do produce milk, but are rarely or never used to produce dairy products for human consumption.
In the Western world today, cow's milk is produced on an industrial scale, and is by far the most commonly consumed form of milk. Commercial dairy farming using automated milking equipment produces the vast majority of milk in developed countries. Dairy cattle such as the Holstein have been specially bred for increased milk production. 90% of the dairy cows in the United States and 85% in Great Britain are Holsteins. Other dairy cows in the United States include Ayrshire, Brown Swiss, Guernsey, Jersey, and Milking Shorthorn (Dairy Shorthorn). The largest producers of dairy products and milk today are India followed by the United States, Germany, and Pakistan.
Increasing affluence in developing countries, as well as increased promotion of milk and milk products, has led to a rise in milk consumption in developing countries in recent years. In turn, the opportunities presented by these growing markets have attracted investment by multinational dairy firms. Nevertheless, in many countries production remains on a small-scale and presents significant opportunities for diversification of income sources by small farmers. Local milk collection centers, where milk is collected and chilled prior to being transferred to urban dairies, are a good example of where farmers have been able to work on a cooperative basis, particularly in countries such as India.
This table below shows the numbers of water buffalo milk production. Cattle milk is produced in a much wider range.Top ten buffalo milk producers â€” 2007 Country Production (tonnes) Note India 59,210,000 * Pakistan 20,372,000