AMINO ACID REQUIREMENTS AND POST-ABSORPTIVE METABOLISM IN DAIRY CATTLE: IMPLICATIONS FOR RATIONFORMULATION

摘要

To the continued challenge of making dairy farming more cost effective is now added the pressure of reducing environmental pollution. Indeed, excretion of N, especially in the urine, is a potential source of water (e.g. nitrates) and air pollution (e.g. N2O, a greenhouse gas, or as small particulate polluting aerosols). Increased cost effectiveness and decreased pollution can be achieved through a reduction in dietary protein for lactating cows, provided productivity is not compromised. Accomplishingthe dual goal of minimizing pollution without compromising productivity requires that dairy rations are better balanced to match supply and requirement (rqt) of proteins.