Correlation of Protein Content of Feedstuffs with the Magnitude of Nitrogen Correction in True Metabolizable Energy Determinations

The relationship between the protein content of feedstuffs and the magnitude of difference between corresponding true metabolizable energy (TME) and nitrogen-corrected TME ( TMEn ) was investigated. Fifty-two samples of feed ingredients, mixtures of ingredients, and mixed feeds were assayed for TME and TMEn . A positive relationship was observed between the protein content of the feed samples and the magnitude of difference between determined TME and TMEn values. The regression equation describing this relationship is Y = . 122X + 3.724, where X equals percent protein and Y the percent difference between TME and TMEn . The corresponding r2 was .60.