milk prep
March 16, 2020

Will Dairy Meet Its 25% Reduction Goal in GHGs This Year?

 |  By: Jim Dickrell

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Back in 2009, the U.S. dairy industry committed to an aggressive goal of reducing greenhouse gas (GHG) emissions by 25% by 2020, using 2008 as its baseline. To put that goal in writing, U.S. dairy industry signed a memorandum of understanding with the United States Department of Agriculture.

Whether the industry has met that goal (studies are currently underway) remains to be seen. But an updated study suggest that the industry has made remarkable strides over the past decade.

That study published in the Journal of Dairy Science shows dairy’s GHG emissions have declined 19.2% per gallon of milk from 2007 to 2017. In addition, total U.S. milk production increased by 24.9% between 2007 and 2017, total GHG emissions from milk increased by only 1%.

It should be noted that these improvements measure changes in productivity from the field to farm gate, and do not include estimates from transportation, processing and retail. The agreement with USDA covers dairy’s entire life cycle assessment. 

Livestock sustainability researchers Jude Capper and Roger Cady published their original study back in 2009 which looked at the environmental impact of dairy production from 1944 through 2007. The results of that study showed that the carbon footprint of gallon of milk had declined 63% over that period. U.S. dairy farmers were also using 90% less land and 65% less water to produce a gallon of milk over that period.

But those results are now 13 years old. Editors of the Journal of Dairy Science requested that Capper and Cady update their research, resulting in the new study published this winter. Along with the 19% decline in GHG emissions, they found:

In 2017, producing a unit of milk required:

    • 74.8% of the cows needed in 2007 for the same amount of milk = 25.2% reduction
    • 82.7% of the feedstuffs needed in 2007 for the same amount of milk = 17.3% reduction
    • 79.2% of the land needed in 2007 for the same amount of milk = 20.8% reduction
    • 69.5% of the water needed in 2007 for the same amount of milk = 30.5% reduction
    • The GHG emissions per unit of milk in 2017 were 80.8% of equivalent milk production in 2007 = 19.2% reduction

There was also a reduction in the amount of waste produced in 2017 vs 2007.

  • In 2017, producing a unit of milk required:
    • 79.4% of the manure produced in 2007 = 20.6% reduction
    • 82.5% of the nitrogen excreted in 2007 = 17.5% reduction
    • 85.7% of the phosphorus excreted in 2007 = 14.3% reduction

The key to all of this is higher efficiency of both feed and milk production and productivity per cow, says Capper and Cady.  

The big question is whether U.S. dairy farmers can continue this remarkable improvement in efficiency and its reduction of inputs needed to produce each gallon of milk. Capper and Cady think it can. “The most recent world record cow, kept in a 360-cow herd in Wisconsin, produced 78,100 lb of milk in a single lactation, which is 241% more than the average U.S. cow in 2017,” they say.

“It, therefore, appears that a genetic plateau for milk production has not yet been reached and that productivity gains similar to those described in this study can continue to be realized into the future.”

Environmental gains by dairy farmers could also be used to improve the social acceptability of dairy production, the say. Other studies show that dairy-alternative beverages, such as almond-based drinks, have a greater water footprint and a less desirable ratio of GHG emissions to their nutrient density index and are limited in essential nutrients compared to milk.

You can read the updated Capper/Cady study here.