The transfer of endogenous nitrogen to the hind-gut digesta of sheep and its relationship with urinary nitrogen excretion were studied concurrently with the estimation of nitrogen balance and of dry matter digestibility in sheep fitted with a re-entrant ileal cannula. Infusion of glucose into the terminal ileum increased the excretion of faecal nitrogen by 1 g/day, while the urinary urea nitrogen excretion decreased by 1 g/day, relative to the respective control levels. Plasma urea nitrogen concentrations remained unchanged. When glucose was infused, the excretion of nitrogen in the faeces was higher than the amount of nitrogen passing the terminal ileum. It is suggested that endogenous urea nitrogen was transferred to the digesta of the hind-gut, where it was incorporated into microbial protein and subsequently excreted in the faeces. The transfer of urea from the blood to either of the fermentative areas of the gut tract is apparently the preferential pathway of urea excretion in ruminants.

Four Merino wethers were each fed a sulphur-deficient, roughage-based ration containing 1'05% nitrogen (79% as urea) and supplying 135 mg sulphur/day. Four other sheep were fed similar amounts of basal ration supplemented with NasS04. This ration supplied 494 mg sulphur/day. Mter 21-day periods the treatment groups were reversed.Supplemental sulphate increased the daily flow of protein nitrogen to the omasum by 2·09 (±0·28) g/day (mean ± S.E.M.) (p<0·001) and changed the nitrogen balance from -2·38 (±0·09) g/day to 0·15 (±0·19) g/day (P

The concentrations of volatile sulphides in the rumen fluid of sheep were determined at intervals after giving single intraruminal infusions of DL-methionine, L-cystine, or L-cysteine. The basal ration fed contained 0�1 % sulphur.