ENVIRONMENT REPORT
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May 24, 2002: Less Gas from Farm Animals
By George Grow
This is the VOA Special English Environment Report.
Scientists in New Zealand have found a way to reduce methane gases released by cows and sheep. The new study
showed that feeding some crops to farm animals can reduce methane gas by as much as sixteen percent. Reports
say the finding could help efforts to reduce greenhouse gases
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harmful gases that cause warming of the Earth.
Methane and other greenhouse gases trap heat from the sun in the atmosphere.
Scientists say increased temperatures on Earth will have serious effects on the
environment, plants, animals, agriculture and sea levels.
Sheep and cattle expel methane gas in their breath. The gas is a product of chemical
processes in their feed. Sheep and cows are two members of a group of animals
called ruminants. About ninety percent of New Zealand’s methane gas releases
comes from ruminants.
In New Zealand, the average cow produces about ninety kilograms of methane each year. Reducing greenhouse
gases is an important goal in New Zealand. It is one of the countries that must reduce its levels of greenhouse
gases under an international treaty called the Kyoto Protocol.
Scientists Garry Waghorn and Michael Tavendale supervised the new study. They found that chemicals in some
grasses can directly reduce the release of methane from sheep and cattle. New Zealand’s agricultural research
center, AgResearch, reported their findings.
The scientists tested different kinds of plants in grasslands where the animals feed. They found that natural plant
chemicals called condensed tannins have a major effect on the amount of methane produced. Condensed tannins
are found in some grasses. They also are found in apples, cocoa and wine, a drink made from grapes. The New
Zealand team studied a legume plant, the lotus, which contains naturally condensed tannin compounds.
AgResearch notes the discovery is only the first step. It says scientists will continue to investigate how diets
containing condensed tannins can be used to lower methane production in farm animals. Scientists say condensed
tannins also are helpful to farm animals in other ways. They increase weight gain and milk production. They also
decrease the risk of some diseases.
This VOA Special English Environment Report was written by George Grow.
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