The effect of time after feeding on the distribution of nitrogen (N) in digesta from various segments of the gastrointestinal tract was studied in sheep given a diet of chopped hay once daily. Four groups of four animals were slaughtered at 2, 8, 16 and 24 h after feeding and digesta were separated into large (> 1180-mu-m), medium (300 to 1180-mu-m) small (45 to 300-mu-m) and fine particles and liquid (< 45-mu-m) fractions. The N pool in the reticulorumen decreased with time after feeding but postruminal N pools changed very little. Changes in N distribution within the reticulorumen reflected reductions in large particles and increases in fine particles and liquid fractions, the intermediate fractions remaining fairly constant.