Quantitative ruminant nutrition - a green science [review]
1993
Leng, R.A. (New England Univ., Armidale (Australia). Dept. of Biochemistry, Microbiology and Nutrition)
Knowledge of quantitative digestion and metabolism in ruminants was developed most rapidly when isotope dilution techniques became easy to apply, facilitated by improved instrumentation and mathematical approaches. The data that accumulated from the quantitative approach led to simple or complex models of animal digestion, metabolism and growth. These in turn led to much questioning of the dogma of feed evaluation and feeding standards as they applied in practice, especially for ruminants fed on poor quality forages. The major breakthroughs have come about by recognition of the nutrients required to balance a ruminant's diet where the animal depends on the end-products of rumen fermentation (i.e. on a forage-based diet). When this is achieved, the increase in efficiency of use of nutrients lifts the overall nutrition of the animal to a level that is well above that predicted from feeding standards, based on the metabolizable energy content of the supplement or the total diet. The understanding, together with the stoichiometry of rumen fermentation, has indicated an important approach to help ameliorate the greenhouse effect, that is, lowering of enteric methane production per unit of feed intake or per unit of animal products from ruminants by strategic supplementation.
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