Abomasal Nitrogen in Steers Fed Soybean Meal, Urea or Urea Plus Two Levels of Molasses

The quantity and quality of nitrogen reaching the abomasum of steers fed SBM, urea, urea and 2.5% molasses or urea and 10.0% molasses were determined using four abomasal fistulated steers in a 4×4 latin square. Total nitrogen reaching the abomasum, estimated by nitrogen:chromic oxide ratios was determined and separated into protein, bound-amino and free-amino nonprotein nitrogen and purine-pyrimidine nitrogen. Quantitative estimates revealed that only 79.4% as much nitrogen reached the abomasum in steers fed urea as in steers fed SBM. Addition of 2.5% molasses to urea increased daily abomasal nitrogen to 92.5% of that from SBM feeding, and addition of 10.0% molasses to urea was of no benefit over 2.5% molasses. While differences between means were not statistically significant (P>.05), significant treatment effects were recorded at P