Studies on the flow of zinc, cobalt, copper and manganese along the digestive tract of sheep given fresh perennial ryegrass, or white or red clover.

1. Sheep fitted with a rumen fistula and either a re-entrant cannula at the proximal duodenum or a re-entrant cannula at the terminal ileum were given twice daily 480-520 g dry matter as fresh perennial ryegrass, or white or red clover. Flows of digesta were corrected to 100% recovery of chronic oxide. 2. The quantities (g/24 h) of zince and cobalt leaving the stomach were significantly greater than those in the food. No significant change was found in the quantities of copper and manganese. Significantly smaller quantities of Co (all three diets) and Zn (all diets except red clover) left the small intestine than those which entered this region. No significant differences in the quantities of Cu and Mn entering and leaving the small intestine were found. Significantly smaller quantities of Zn, Co, Cu and Mn were excreted in the faeces than entered the large intestine. 3. From the flow results it was determined that there was a significant net secretion of Zn and Co in the stomach, and a significant net absorption of Zn (except with the red-clover diet) and Co from the small intestine, and of Zp Co Cu and Mn from the large intestine.