<P> According to the BBC , the era factory farming per se in Britain began in 1947 when a new Agriculture Act granted subsidies to farmers to encourage greater output by introducing new technology , in order to reduce Britain 's reliance on imported meat . The United Nations writes that `` intensification of animal production was seen as a way of providing food security . '' In 1966 , the United States , United Kingdom and other industrialized nations , commenced factory farming of beef and dairy cattle and domestic pigs . From its American and West European heartland factory farming became globalised in the later years of the 20th century and is still expanding and replacing traditional practices of stock rearing in an increasing number of countries . In 1990 factory farming accounted for 30 % of world meat production and by 2005 this had risen to 40 % . </P>
when did factory farming begin in the us
1966