Leng R A 2009 A strategy for selecting and managing livestock species according to their potential to use feeds non-competitive with human needs  Proceedings MEKARN Workshop on  Livestock, Climate Change and the Environment (Editors: Reg Preston and Vo Lam ), An Giang University, Vietnam, 16-18 November 2009 http://www.mekarn.org/workshops/environ/Abstracts/leng.htm