Producing milk uses large quantities of land, energy and feed, but rbST -- the first biotech product used on American farms -- has been in agricultural use for nearly 15 years. Now it is found to reduce the carbon hoofprint by easing energy, land and nutritional inputs necessary to sustain milk production at levels sufficient to meet demand.

This research found that, compared to a non-supplemented population, giving rbST to one million cows would enable the same amount of milk to be produced using 157,000 fewer cows. The nutrient savings would be 491,000 metric tons of corn, 158,000 metric tons of soybeans, and total feedstuffs would be reduced by 2,300,000 metric tons. Producers could reduce cropland use by 219,000 hectares and reduce 2.3 million tons of soil erosion annually.

In 2007, there were 9.2 million cows in the United States. For every one million cows supplemented with rbST, the world would see an environmental saving of 824 million kilograms of carbon dioxide, 41 million kilograms of methane and 96,000 kilograms of nitrous oxide. For every one million cows supplemented with rbST, the reduction in the carbon footprint is equivalent to removing approximately 400,000 family cars from the road or planting 300 million trees.

"Supplementing cows with rbST on an industry-wide scale would improve sustainability and reduce the dairy industry's contribution to water acidification, algal growth, and global warming," says Judith L. Capper, Cornell post-doctoral researcher, and the lead author of the new paper in PNAS.

"Sustainability is important in agricultural production, with an emphasis placed upon meeting human food requirements while mitigating environmental impact," said Dale Bauman, an author of the study. "This study demonstrates that use of rbST markedly improves the efficiency of milk production, mitigates environmental impact including greenhouse gas emissions and reduces natural resource requirements such as fossil fuel, water and land use."

Cornell funded the research.

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Journal Reference:

1. Judith L. Capper, Dale E. Bauman, Euridice Castaneda-Gutierrez, and Roger A. Cady. The Environmental Impact of Recombinant Bovine Somatotropin (rbST) Use in Dairy Production. Proceedings of the National Academy of Sciences, June 30, 2008