Scientists have developed a serum to reduce methane gas in burping sheep, cows and other ruminants to combat global warming, a German magazine reported on Monday. The Hanover-based monthly Technology Review will report in its July issue that Andre-Denis Wright, a molecular biologist at Australia's CSIRO Institute, has found a vaccine that reduced the methane emissions of sheep by eight percent. The magazine said that scientists believe the amounts can be reduced even further and more testing is planned. Sheep produce 20 grams of methane each day, or seven kg per year, the magazine with 80,000 subscribers reported. Cows produce...