Energy or nitrogen supply to sheep fed Acacia cyanophylla Lindl. leaves-based diets : effects on intake and digestion

摘要

Recent works done in our laboratory showed that the nutritive value of Acacia cyanophylla Lindl. leaves is low. High content of condensed tannins in acacia (3 to 7%) seems to be the causative factor. In this paper, we report preliminary results of a study dealing with the effect of energy (spineless cactus) or nitrogen (urea) supply on intake and digestion by sheep fed acacia-based diets. Four diets were tested according to a 4x4 Latin square design on rumen fistulated sheep (initial liveweight 47 kg). All diets included air-dried acacia leaves ad libitum, 176 g DM barley, 30 g mineral and vitamin supplement (control, D1) and supplemented with 15 g urea (D2), or 300 g DM cactus (D3), or 15 g urea and 300 g DM cactus (D4). Each experimental period lasted 25 days (15 days for adaptation and 10 days for measurements).