California milk cap.
February 11, 2020

California’s Dairy Carbon Footprint Down 45% Since 1964

Top Story  |   |  By: Jim Dickrell

The amount of greenhouse gas emissions (GHG) per gallon of milk produced by California dairy farmers is down more than 45% over the past 50 years, according to a new study published by the Journal of Dairy Science.

“The study documents the productivity, efficiency and overall sustainability of milk production in California and the critical role dairy cows play in regenerative agricultural practices and sustainable food systems,” says Ermias Kebreab, an animal scientist and an associate dean of global engagement with the University of California at Davis. The study looked at GHG emissions and water use from 1964 through 2014.

Kebreab and graduate student Anna Naranjo conducted a life-cycle environmental assessment of California dairy farm production. The reduction in GHG emissions came primarily from improved milk production efficiency through better nutrition, reproduction, cow comfort and overall management.

The amount of water used per unit of milk improved even more than GHG emissions, dropping 88% per gallon of milk due to improved feed crop production and water use efficiency.

“The study shows we are producing milk more efficiently and sustainably, minimizing our climate footprint in the process,” says Richard Wagner, a San Joaquin dairy farmer and chairman of the California Dairy Research Foundation (CDRF).

In 1964, California cows produced an average of 10,810 lb of milk per cow per year. In 2014, that number had jumped to 23,785 lb./cow. In 1964, California dairy farmers were milking just 790,000 cows. Fifty years later, that number had also more than doubled to 1.781 million.

Today, more than 40% of the dairy feed ingredients fed to California dairy cows come from agricultural by-products, such as almond hulls, citrus and tomato pulp, culled carrots and other products not suited for human use.

“Cows are natural bio-processors and up-cyclers of nutrients,” says Kevin Comerford, CDRF chief science officer. “As a result, cows will continue to play essential roles in healthy, sustainable food systems all over the world. This study demonstrates the environmental benefits in California, where dairy farms have been especially successful in recycling and repurposing resources.”

Researchers also note that the estimated 45 percent reduction in GHG emissions is likely conservative because it does not take into account large solar arrays that have been installed on more than 150 dairy farms. Numerous California dairy farms are also in the process of installing methane capturing systems that will produce liquid biogas, further reducing the industry’s GHG footprint.

You can read more about the study here.