AbstractThe objective of this study was to evaluate the nutritive value of Cistus salvifolius leaves. C. salvifolius leaves contain high levels of crude protein (CP), acid detergent lignin (ADL) and crude saponins and low levels of fibre and condensed tannins. Gas production at the different periods of incubation of C. salvifolius leaves was low at 72 h, varying between 8 and 24 ml/200 mg DM. However, addition of polyethylene glycol to the leaves increased gas production, doubling at every incubation time (7.9 vs. 15.0 ml/200 mg DM at 72 h). Losses in DM and CP at the different incubation times in the rumen reached about 47 and 51%, respectively in 48 h. Lag times of about 6 h were observed in DM disappearance, whereas in crude protein disappearance lag times reached 24 h.