Ruminal Nitrogen Metabolism: Perspectives for Integration of Microbiology and Nutrition for Dairy

Relationships between means from data in multiple trials in which sheep were faunated or defaunated. Panel A shows a constant relationship reported for efficiency of microbial protein synthesis [EMPS; g of microbial N flowing to the duodenum per kg of OM truly digested (OMD) in the rumen]. Panel B shows the reported relationship for duodenal flow of microbial N. However, if the 2 high points are omitted, then the slope becomes greater than 1 (panel C). If a quadratic polynomial is evaluated (panel D), the intercept was P>0.05 from zero, but the x² coefficient was P<0.001 from zero. Data from Hristov and Jouany (2005).