Three rumen fistulated and catheterized sheep were used to study portal recovery of continuously intraruminally infused short-chain fatty acids (SCFA). Each sheep received six treatments: 0, 60, 120, 180, 240 and 300 mmol h−1SCFA infused for 8 h in a semi-fasted state. The infused SCFA had a molar proportion of 65:20:15 (acetate:propionate:butyrate). [1 -13C]Na-acetate was infused intravenously during the experiment for measurement of portal drained viscera (PDV) metabolism and irreversible loss rate (ILR) of acetate. Portal blood flow was measured by ultrasonic flowprobes. Portal blood, arterial blood and rumen liquid were sampled during the last 4 h of the experiments.