How Scientists Measure Gaseous Cow Emissions

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How Scientists Measure Gaseous Cow Emissions
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Cows Produce Gas

• Methane is one of the gases produced by cows when
  they digest food.
• Cows release methane into the air when they fart
  and belch.
• Cow manure also produces methane.
• Some amount of methane in our environment is
  normal, but in recent years it has increased and
  is harming our planet by adding to global warming.

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Scientists Can Measure Gas

• To measure the amount of gas a cow can produce,
  researchers put the cows into large bubble tents.

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The Cows Live in the Bubble

• Each bubble holds 8 cows.
• Each group of 8 eats 300 lbs. of food daily
• How much manure will they make each day?

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Inlet Location

• The outside air goes into the bubble from the
  inlet location.
• Photo acoustic gas analyzers measure the gases in
  the air as they pass through the filter.

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Outlet Location

• The gas from inside the bubble is sucked through
  the tent and back outside by large fans.
• The speed of the fans has to be calculated in the
  gas measurements.

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Negative Pressure System

• The gases in the air are measured again as they
  pass through the filters and back outside.
• Because the air is moving from inlet to outlet,
  it is considered a negative pressure system.

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Security

• The delicate measuring devices are kept locked to
  be sure no one tampers with the equipment, which
  could change the results of the experiment.

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Experiment

• In each bubble, researchers are trying a
  different method of eliminating the gases.

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Which method will work best to eliminate gaseous
emissions?

• Bubble 1 An acidifier, called sodium
  bisulphate, is sprinkled on the manure to kill
  the bacteria.
• Bubble 2 This is a control group nothing is
  done.
• Bubble 3 The manure in this pen is raked 3
  times each week with a chain harrow (a large rake
  pulled by an ATV) to expose the bacteria to air,
  which kills it.
• Bubble 4 The manure in this pen is scraped out
  each week with a Bob Cat and taken to another
  location.

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Conclusion

• At the end of two weeks, the cows are returned to
  their home in the dairy and the measurements that
  were taken of the air at the inlet and outlet
  locations are analyzed.
• The results of the experiment are written in a
  report.
• The report is examined and discussed by other
  scientists.
• This experiment must be done several times before
  an accurate conclusion can be reached.

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Appreciation

• Thanks to Lisa Nuckles, a graduate student in the
  Animal Biology Graduate Group at the University
  of California at Davis, for sharing her
  experiment with us.
• For a clip of Lisa explaining her experiment,
  click here.

• See a video of Lisa Nuckles speaking about her
  cow experiment Click here