The relationship between dairies and the Central Valley's polluted air changed dramatically Wednesday morning when a UC Davis researcher reported that dairies produce far less pollution than previously believed. Frank Mitloehner, who has been running a "bovine bubble" experiment to measure gases coming from cows, said his study found cows create only half the pollutant amounts previously counted by air regulators. What's more, most harmful gases come from a cow's belches -- not its manure, he found. The burgeoning dairy industry in the Central Valley has been targeted by environmental groups that have accused dairymen of contributing to the already-dirty...