Productions efficiency of ruminants: feed, nitrogen and methane

This chapter discusses the production efficiency of ruminants, particularly cattle, in relation to feeds, nitrogen excretion and methane emission. Focus is given on the production efficiency of cattle, primarily that of dairy cattle, at the animal level. Improvements in production efficiency are discussed with respect to the amount of feed required for production and associated losses of nitrogen and methane from cattle. Covered in detail are the efficiency of converting feed to product, production level efficiency, total efficiency and human-edible efficiency of different livestock production systems, production efficiency and emissions (nitrogen and methane) and production level, nitrogen efficiency and methane production.