Ruminants establish a symbiotic relationship with microorganisms in the rumen by which the animal provides nutrients and the proper environmental conditions for fermentation of feeds, and microorganisms provide the possibility of utilizing fibre and supply volatile fatty acids and newly synthesized microbial protein as the main sources of energy and protein for the animal. However, this symbiotic relationship suffers from several energy (in form of methane) and protein (in form of ammonia N) inefficiencies (Van Nevel and Demeyer, 1988). These losses not only reduce production performance, but also contribute to release of pollutants to the environment (Tamminga, 1996; Weimer, 1998).
展开▼
