rbST

“The environmental impact of recombinant bovine somatotropin (rbST) use in dairy production”, a paper promoting the use of rbST can be found at:

http://www.pnas.org/content/105/28/9668.abstract?cited-by=yes&legid=pnas%3B105/28/9668


The conclusion is a forgone conclusion, “Meeting future U.S. milk requirements from cows supplemented with rbST conferred the lowest AP, EP, and GWP, with intermediate values for conventional management and the highest environmental impact resulting from organic production. Overall, rbST appears to represent a valuable management tool for use in dairy production to improve productive efficiency and to have less negative effects on the environment than conventional dairying.”

I would question the impact of rbST. Monsanto has claimed some fairly high numbers of cows supplemented with rbST.

Is there any indication in the milk per cow over a large number of years of any rbST bump? Or is there a fall off as more milk buyers are requiring milk from cows not treated with rbST?