Shooting up cows with artificial growth hormones increases the sustainability of the dairy industry, claims a new study published in Proceedings of the National Academy of Sciences. “Giving rbST to 1 million cows would enable the same amount of milk to be produced using 157,000 fewer cows,” says the study, thus easing the impact that giant dairy-cow operations have on the land, water, and air. “Supplementing cows with rbST on an industry-wide scale,” says researcher Judith Capper, would “reduce the dairy industry’s contribution to water acidification, algal growth, and global warming.” So would getting rid of CAFOs altogether, but maybe that’s just quibbling. Artificial growth hormones have been banned in the European Union out of concern for animals’ health; hormones have also been linked to breast, prostate, and colon cancer.