Standard feed value

Abstract

Traditional feed evaluation systems determine fixedand additive feed values of feedstuffs. The NorFor system, however, is a ration evaluation system and in principle each individual feedstuff has no fixedfeed value because of the interactions in the digestion and metabolism of nutrients. Nevertheless, there is a need to compare feedstuffs for trading purposes or in the optimization of concentrate mixtures by linear programming in the feedstuff industry. Therefore, we calculate feed values based on standardized conditions, where important model variables are fixed,.g. fractional passage rates and efficiencyin the microbial protein synthesis (see Table 13.1). These fixedvalues represent feed rations for diets used in Denmark, Iceland, Norway and Sweden.