Paul Saladino· MD
number two on every label that you look at when it says protein it's a crude protein value now you know back in the 1860s approximate analysis I think that's right maybe it was 1880s the proximate analysis testing system was developed and just trying to quantify the nutritive value of feedstuffs feed animal's food for humans the way you determine crude protein is you determine the total nitrogen in any sample and then you multiply that percent nitrogen by 6.25 and that then becomes your percent crude protein because we assume that all the nitrogen that we found in that feed stuff was in protein and all that protein was 16 percent nitrogen