Department of Animal Sciences, College of Agriculture, University of Shiraz, Shiraz, Iran
The chemical composition, degradability coefficients (in situ) and ruminal-intestinal disappearance (mobile bag procedure) of dry matter (DM) and crude protein (CP) were evaluated for olive cake (OC) silages treated (DM basis) with additives as follows: (1) untreated OC, (2) OC + 0.5% urea, (3) OC + 0.4% formic acid, (4) OC + 8% molasses, (5) OC + 0.5% urea + 8% molasses, (6) OC + 0.5% urea + 0.4% formic acid, (7) OC + 8% molasses + 0.4% formic acid and (8) OC + 8% molasses + 0.4% formic acid + 0.5% urea. The highest reduction in cellulose and ADF content was found for treatment 8 (120 and 117 g kg-1 DM, respectively), as compared with the raw material (not ensiled). Taking into consideration the chemical composition, pH values, and the general appearance of silages, ensiling of OC with additives preserved well and enhanced the nutritive value of olive cake. Ruminal maximum potential degradability of DM (a+b), effective and rapid degradability and rate of degradation of treatment 8 were higher than others. The same trend was found for CP except fraction “a” which was highest for treatment 6. Mean ruminal DM (P<0.05) and CP disappearances in treatment 8 after 12 hrs incubation were higher than the other treatments. Intestinal digestibility of undegraded DM for treatment 5 was higher (P<0.05) than treatment 6 with no differences among other treatments. Intestinal digestibility of undegraded CP for treatments 3, 5, 6 and 7 was higher (P<0.05) than the other treatments. Total tract DM disappearance of treatments 4, 5 and 8 was higher (P<0.05) than others. Total tract CP disappearance of treatment 8 was higher (P<0.05) than treatment 4. Results indicated that treating OC before ensiling with 8% molasses, 0.4% formic acid and 0.5% urea (DM basis) could provide a good and economical source of a non-conventional feed in areas where OC is available; thus, it helps to improve the diet formulation for ruminants.