The present study aimed to evaluate the influence of two different source of forage (haysilage and hay) during the lactation on organic matter digestibility (OMD) in buffalo cows. Lactating buffaloes (n = 40) at 29.6 days in milk (DIM) were equally divided as function of previous milk yield into Group 1 (meadow hay, n = 20) and Group 2 [haysilage (Lolium multiflorum), n = 20]. The diets were isoenergetic [0.92 milk unit forage (MUF) on dry matter basis] and isoproteic (16.2 % crude protein on dry matter basis) and administred as total mixed ration (TMR). From all the buffaloes, for each group and in two sampling time (first sampling, DIM = 74.0 and second sampling, DIM = 129.0) the faeces were collected in order to evaluate the in vivo digestibility. Overall the trial, the subjects fed haysilage showed higher OMD than those fed hay (66.1 vs 45.7; P<0.01), moreover the in vivo digestibility was affected by the DIM, in particular in the group fed hay (40.6 vs 53.4; P<0.0001, respectively). This work underlines the importance of the administration of the haysilage (Lolium multiflorum) as source of high quality forage because it gives, overall the lactation, more nutritive principles compared with meadow hay
