Dairy genetics, nutrition, herd management and improved animal welfare over the past 60 years have resulted in a modern milk production system that has a smaller carbon footprint than mid-20th century farming practices, says a Cornell University study in the Journal of Animal Science (June 2009).The same researchers also found that cows treated with rbST needed less feed and emitted less CO2. Let the debate of whether organic or regular milk is greener commence.
The study shows that the carbon footprint for a gallon of milk produced in 2007 was only 37 percent of that produced in 1944. Improved efficiency has enabled the U.S. dairy industry to produce 186 billion pounds of milk from 9.2 million cows in 2007, compared to only 117 billion pounds of milk from 25.6 million cows in 1944. This has resulted in a 41 percent decrease in the total carbon footprint for U.S. milk production.
Efficiency also resulted in reductions in resource use and waste output. Modern dairy systems only use 10 percent of the land, 23 percent of the feedstuffs and 35 percent of the water required to produce the same amount of milk in 1944. Similarly, 2007 dairy farming produced only 24 percent of the manure and 43 percent of the methane output per gallon of milk compared to farming in 1944.