The dairy industry has made huge advances in efficiency over the past 60 years. According to USDA data, in 1944, the year when dairy cow numbers peaked at 25.6 million head, total milk production was 53 billion kg (Figure 2; http://www.nass.usda.gov/Data_and_Statistics/Quick_Stats/). By contrast, the 2007 US dairy herd comprised 9.2 million animals, producing a total of 84 billion kg of milk. This is equivalent to a four-fold increase in the annual milk yield per cow, progressing from 2,074 kg/cow in 1944 to 9,193 kg/cow in 2007.

Source: J. L. Capper1, R. A. Cady2 and D. E. Bauman1

1Department of Animal Science, Cornell University, Ithaca, NY; 2Monsanto Company Animal Agricultural Group, St Louis, MO: ‘Increased Production Reduces The Dairy Industry’s Environmental Impact’:

The carbon footprint of dairy production in 1944 compared to 2007 is shown in Figure 3. The left-hand bars are quantified according to the process basis, i.e. per cow, and, as expected, low-producing cows characteristic of the 1944 dairy system had a lower carbon footprint than high-producing modern cows. However, the advantage conferred by improved productive efficiency of modern milk production systems is clearly demonstrated when the data are expressed on an outcome basis: from 1944 to 2007 there has been a 63% reduction in the carbon footprint per kg of milk. Interestingly, many of the characteristics of 1940’s dairy production (low-yielding, pasture-based, no antibiotics, inorganic fertilizers or chemical pesticides) are similar to those of modern organic systems. Indeed, studies investigating the environmental impact of organic systems have also described increases in the quantity of resources required and carbon footprint per kg of milk compared to conventional production (Capper et al., 2008, de Boer, 2003, Williams et al., 2006).