September 30, 2009, West
Lafayette, IN – Any calculation of the carbon footprint of a gallon of milk
needs to include fuel used by tractors and trucks, as well as electricity
consumed by milking machines and refrigerators. But how much gas is coming from
the cows themselves?
September 30, 2009, West
Lafayette, IN – Any calculation of the carbon footprint of a gallon of milk
needs to include fuel used by tractors and trucks, as well as electricity
consumed by milking machines and refrigerators. But how much gas is coming from
the cows themselves?
That’s the question Purdue
University researchers are investigating as they start a new study aimed at
measuring greenhouse gases from dairy cows. Albert Heber, principal
investigator and a professor of agricultural and biological engineering, said
the study is part of an industry-wide effort to reduce greenhouse gas emissions
related to fluid milk.
“The dairy industry
understands that in order to adopt best practices that will help lower greenhouse
gas emissions in the dairy supply chain, it must first know where the
mitigation opportunities exist,” Heber said.
The study is being funded
by the Innovation Center for U.S. Dairy and is one of several studies that will
be used to measure the entire carbon footprint of fluid milk – from the farm to
the glass. Researchers from the University of California Davis, Cornell
University, the University of Minnesota and Washington State University are
collaborating on the project.
“Measuring the greenhouse
gas emissions of dairy cows will help determine the extent to which the dairy
industry contributes to U.S. greenhouse gas emissions,” said Rick Naczi, the
group’s executive vice president of strategic industry analysis and evaluation.
“Preliminary scan level research was conducted last year that showed the dairy
industry accounts for less than two percent of total U.S. greenhouse gas
emissions. Now, we are expanding our efforts by partnering with respected
academic institutions like Purdue and engaging in extensive research to assure
that our efforts are based on sound science as we address the environmental,
economic and social importance of reducing our carbon footprint.”
Carbon dioxide, methane
and nitrous oxide will be monitored at five barn sites and two manure lagoons
in Indiana, Wisconsin, California, Washington and New York. Mobile laboratories
set up for the National Air Emissions Monitoring Study, of which Heber also is
principal investigator, are being used to take the measurements in this study as
well.
“We began collecting some
greenhouse-gas data as early as 2007, but now we have all the equipment we need
and we've been getting data on all parameters of it for about a month,” said
Bill Bogan, operations manager for the two studies.
Tubes will draw air from
each of several exhaust fans and background locations. The air will be fed into
a series of analyzers that measure the concentrations of the gases. Those
concentrations can be used to determine the amount of each gas emitted for a
particular time period and per animal. Data will be updated every minute.
Heber said the gas comes
from both the cow and the manure. Manure gas is easiest to address. Different
manure management practices may increase or decrease total emissions, he said.
“The type of storage and
handling procedures may contribute to how much gas is escaping from the
manure,” Heber said.
Most of the previous
studies on dairy greenhouse gas emissions were done in Europe and Canada and
don't reflect U.S. climate and management practices. This study will provide
country- and region-specific greenhouse-gas emission rates from U.S. dairy
operations, which can be used by the Intergovernmental Panel on Climate Change
for modeling emissions.
Data will be collected
through Jan. 31.
