How Scientists Measure Gaseous Cow Emissions

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.

Scientists Can Measure Gas

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

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?

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.

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.

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.

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.

Experiment

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

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.

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.

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