An issue
http://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=115x177491">from another post about methane release by cattle raised for beef. With a tip of the hat to
groovedaddy and
kestrel91316.
http://www.canada.com/topics/news/national/story.html?id=782eb88c-4695-44a8-839f-d1660752a8ce">Less grass means less gas, cattle researcher saysLinda Shepertycki, Winnipeg Free Press
Published: Thursday, October 30, 2008
WINNIPEG - A University of Manitoba scientist says he's figured out how to cut the amount of greenhouse gas belching from cows by as much as 200 litres a day - feed them grain instead of grass.
For the past four years, Prof. Ermias Kebreab has been analyzing cow burps at the National Centre for Livestock and the Environment south of Winnipeg to measure the amount of methane dairy cows produce when they are fed different types of food.
About 98 per cent of the methane from a cow is emitted through its mouth - "only two per cent comes out the other way," said Kebreab.
...
The grass-fed cows produced 600 to 700 litres of methane per day compared to about 500 litres per day per grain-fed cow, said Kebreab.
This isn't the first study showing an increase in methane from grass-fed cattle. The proposed mechanism is that cellulose (plant fiber) takes longer to digest in the cows' stomachs, allowing methane to be generated by fermentation.
This directly contradicts the prevailing notion that sugars in grain are fermented in the cows' stomachs and produce methane at a much higher rate than grass does.
Questions that will be raised with the recent studies:
1. The methodology in every such study I've seen -- three so far -- measures belched methane, from the mouth. Methane in flatus was not measured, but Prof. Kebreab states that 98% of the methane comes out the front, not the back. Critics will challenge this assertion and the methodology of only recording the belched methane.
2. One study was funded by a dairy institute, which has a financial interest in feeding cows grain instead of grass. The funding sources will have to be scrutinized, although there is no reason to assume that this is a "purchased" scientific finding.
If you see anything else about this, please post it.
--p!