Abomasal Nitrogen in Steers Fed Soybean Meal or Urea

Quantitative and qualitative estimates of nitrogen in the abomasum were studied with four steers fitted with permanent abomasal fistulas and fed ground ear corn rations supplemented with SBM or urea. Significantly more total nitrogen was recovered in the abomasum of steers fed SBM than in steers fed urea. More of the nitrogen in the abomasum was in the form of protein and less as free amino and purine-pyrimidine nitrogen when SBM was fed than when urea was fed. Molar ratios of individual amino acids in abomasal contents were not significantly affected by source of supplemental nitrogen.