Environmental Engineering Reference
In-Depth Information
nationwide mean of less than 3 kg/capita (Buck 1937). Even by the 1960s the
average per capita meat intake was below 10 kg/year in all of Asia's most populous
nations, China, India, and Indonesia.
Not surprisingly, intakes were higher among richer urbanites, rations were even
higher for some armies, and premodern meat consumption was relatively high in
North America as well as in Argentina and, later, in Australia and New Zealand.
The dietary transition began i rst in the growing industrial cities of Europe and
North America. Germany's average annual per capita meat consumption was less
than 20 kg before 1820, but it was almost 50 kg by the end of the century (Abel
1962; French meat consumption remained low until 1850, then doubled to more
than 50 kg by the 1930s (Dupin, Hercberg, and Lagrange 1984); and the British
per capita consumption had roughly tripled during the nineteenth century to almost
60 kg by the year 1900 (Perren 1985). This pre-1900 dietary shift had a fairly limited
impact on the biosphere, and not just because it affected only a small share of the
world's population. The key explanation of this modest impact is in the prevailing
modes of animal food production.
The traditional raising of domestic animals did not compete for arable land with
food crops. Free-ranging poultry received only small amounts of grain as an occa-
sional supplement, free-roaming pigs rooted for any edible biomass and were fed
any available crop and kitchen waste, and cattle and water buffaloes, as well as
goats and sheep, were raised by grazing (on grasslands as well as on harvested i elds)
and by feeding crop residues and hay. These animals made only a marginal addi-
tional claim on arable land, but they were also relatively inefi cient users of feed
and took much longer to reach slaughter weight than modern breeds. Chicken were
commonly killed only at 3-6 months of age (compared to about six weeks for
today's mass-produced, and also signii cantly heavier, broilers), while pigs attained
their slaughter weight only after 12-15 months (compared to just short of six
months from weaning to slaughter for modern pigs).
In 1900 there were about 1.3 billion large domestic animals, including 500
million bovines, about 200 million pigs, 750 million sheep and goats, and 100
million horses. If we were to assume that 10% of all animal food production in
1900 was energized by concentrate feeding (a generous allowance), and if we
were to use high take-off rates (80% of all pigs and 15% of all bovines slaughtered
annually) and a feed/live weight conversion efi ciency of 6:1 for pigs and 10:1 for
cattle, we would end up with a total feeding requirement of less than 40 Mt of grain
equivalent. This could be produced, even if we assume average low yields of just 1
t/ha, on some 40 Mha of arable land, or not even 5% of about 850 Mha of the
