PART ONE: THE HISTORY, GEOGRAPHY AND BIOLOGY OF MILK
The origins of dairy farming
Although sheep, cattle and goats are thought to have been domesticated in parts of the Middle East and central Asia over 9,000 years ago there is no direct evidence that these animals were used to supply milk. Written texts, paintings and drawings from around 6,000 years ago provide the earliest firm evidence of dairy farming (Pringle, 1998). Molecular and stable isotope evidence for dairy fat residues in pottery suggests that the exploitation of animals for milk was already an established practice in Britain when farming began in the fifth millennium BC (Copley et al., 2003). Although this sounds like a long time ago, in evolutionary terms it is very recent history and early dairy farming would have been practised on a relatively small scale. Hominid (modern humans and our forerunners) fossils date back to nearly seven million years ago (Cela-Conde and Ayala, 2003). If seven million years were represented as a twelve-hour clock, starting at midday, humans would have started dairy farming 37 seconds before midnight.
Furthermore, it is important to note that around 70 per cent of people in the world do not consume cow’s milk, even if they wanted to, it would make them ill due to lactose intolerance (see Lactose intolerance).
Milk production today is big business. Currently in the UK 2.2 million cows are held in 22,000 dairy holdings. The total value of the production of milk in the UK is estimated to be £2.7 billion. This is more than the value of production of beef, lamb, pig or poultry meat and around three times the value of the production of fresh vegetables (Defra, 2005). Excluding suckled milk, each cow now produces around 20 litres of milk per day, which equates to around 7,000 litres of milk yearly (Defra, 2005). Selective breeding and high protein feed has increased the average yield per cow from nine litres (16 pints) per day to 22 litres (39 pints) per day in just a few cattle generations.
A common misconception is that it is natural for cows to produce milk constantly. This is not the case; just like us, cows only produce milk after a nine-month pregnancy and giving birth. Today’s large-scale intensive dairy farming employs a highly regulated regime of cycling pregnancy and lactation concurrently, meaning that cows are both pregnant and being milked at the same time for most of each year. This intensive physical demand puts a tremendous strain on the dairy cow and, as she gets older, infertility and severe infections causing mastitis and lameness cuts short her economic and productive life (The Dairy Council, 2002). The average lifespan of a modern dairy cow is only about five years – that is after three or four lactations, when naturally she may live for 20 to 30 years.
Since 1960, global milk production has nearly doubled (Speedy, 2003). Around three-quarters of the world’s population do not drink milk, but among those who do, the pattern of consumption varies widely between countries. Data collected by the United Nations Food and Agriculture Organisation (UNFAO) in 2002 provides figures for the consumption of milk (excluding butter) in kilograms per capita per year for over 170 countries (FAOSTATS, 2002).
Figure 1.0 Consumption of milk in selected countries compared to world consumption. Data from FAOSTATS, 2002.
As shown in Figure 1.0 the level of milk consumption varies widely between countries, even between neighbouring countries in the same continent. For example, in Portugal 219.7kg of milk is consumed per person per year whereas in Spain the figure is considerably lower at just 158.3kg per person per year.
The highest levels of consumption are seen in Europe. In Sweden for example, a massive 369.4kg of milk is consumed per person per year, with Finland close behind at 350.6kg. Other countries consuming large volumes of milk include the Netherlands (345.7kg), Switzerland (332.4kg), Albania (298.8kg), Austria (293.3kg), Ireland (279.5kg), France (275.5kg) and Norway (275.1kg). In the US 261.8kg of milk is consumed per person per year, and in the UK the figure is 230.9kg. Whereas the average amount of milk consumed per person per year on a global scale is just 79kg.
The lowest levels of consumption are seen in Africa and Asia. In the Democratic Republic of the Congo a mere 1.6kg of milk is consumed per person per year. Other countries consuming small volumes of milk include Liberia (1.8kg), the Democratic People’s Republic of Korea (3.9kg), Mozambique (4.5kg), Vietnam (5kg), China (13.3kg) and Thailand (18.8kg). With levels this low, it is reasonable to assume that many people in these countries and others do not consume any milk or milk products at all.
It could be argued that the low level of milk consumption seen in developing countries just reflects the fact that people cannot afford to buy milk. However, in Japan for example (not a developing country), milk consumption is very low at only 67.1kg. Most people in the world do not drink milk; their reasons may be cultural, economical, historical or biological. For example, most of the world’s population are lactose intolerant (see Lactose intolerance). But many of us think of milk as a fundamental component of a healthy diet. Why is this? Is milk the only source of some obscure essential nutrient? Or is milk unique in that it contains all the nutrients that we require?