Dairy Herd alert: Proper diet crucial in reducing cow emissions 1/31

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Cows contribute less pollution than once thought

By Dairy Herd news source (1/31/2005)

 

According to a study released last week by the University of

California-Davis, dairy cows produce only half the amount of

ozone-forming gases that researchers had previously thought.

 

Frank Mitloehner, air-quality management specialist at the UC Davis,

reported that dairy cows and their waste contribute about 6.4 pounds of

volatile organic compounds per year -- half the previous estimate of

12.8 pounds. The 12.8-pound figure was, by most accounts, based on a

faulty science. Back in 1978, a consultant made an erroneous assumption

based on a study that was done 40 years prior to that, giving false

currency to the 12.8-pound number.

 

Volatile organic compounds cause ozone or smog to form in the

atmosphere. Smog is a big health concern in California's central valley.

 

Another surprising conclusion from Mitloehner's study: Most of a dairy

cow's contribution to smog comes not from her manure, but from her

belching. That is very significant, because strategies aimed at capping

or aerating manure-storage basins, such as lagoons, may prove less

important than feeding or managing a cow correctly.

 

In a previous trial, Mitloehner found that switching from a 20-percent

crude protein ration to a 14-percent protein ration reduced ammonia

emissions from cows significantly.

 

He also has found that certain bedding types, such as rice straw, can

help control ammonia and dust emissions.