Technical Orientation: Microbial Protein: More is More!

The title of my first invited presentation and review article from 1996 stands the test of time. Microbial protein still is the major source of protein for the high-producing dairy cow and is enriched in all of the amino acids needed for milk production except histidine. I will explain key concepts we have learned in those 30 years and gaps remaining, with my expectations for how to fill those gaps. I will emphasize maximizing ruminal fiber degradation with proper diet formulation and adherence to physical fiber needs. Microbes need adequate rumen-degraded protein (RDP) to maximize microbial protein, although there is the question of “optimal” versus “maximal” RDP to consider. When we optimize microbial protein, we help set up approaches to improve metabolizable amino acid formulation and thereby milk protein responses.