The oil of cashew shells, when added to cattle’s diet, may reduce by 90% the methane gas produced when they belch (see “The Meat of the Matter,” cover story, July/August 2008). Reuters reported in June that the Japanese oil refiner Idemitsu Kosan Co., Ltd. is applying for a patent for this new feed additive. With upwards of 1.5 billion heads of cattle in the world, according to the International Erosion Control Association, it’s unlikely that current levels of cast-off shells would meet demands. Cashew trees are native to Brazil and grown in hot, humid climates, and researchers will need to consider whether upping the production level of this rainforest crop (as well as generating the energy needed to produce and transport the oil) is an ecologically sound practice. The feed additive has been researched in the lab only and has yet to be actually fed to cattle.