Two agricultural by-products (crude olive cake, OC and a mix of greenhouse wastes of tomato and cucumber, GHW) were evaluated for ruminal dry matter (DM), crude protein (CP), acid detergent fiber (ADF) and neutral detergent fiber (NDF) degradation kinetics. Duplicate bags containing 3 g ground raw material each were incubated in the rumen of two ruminally cannulated Assaf rams for 4, 8, 16, 24, 48 and 72 h. Rate and extent of ruminal degradation were estimated. Significant effects of by-product type were observed in rapidly soluble and potentially degradable fractions, and degradation rates of DM, CP, ADF and NDF. The rapidly soluble DM, CP, ADF and NDF fractions were 16.19, 15.21, 10.64 and 14.06% for GHW, and 7.21, 6.64, 6.00 and 5.62% for OC. The potentially degradable DM, CP, ADF and NDF fractions, respectively, were 55.82, 62.30, 49.40 and 55.09% for GHW, and 47.61, 44.26, 46.34 and 48.53% for OC. The DM, CP, ADF and NDF disappearance in GHW were higher (P < 0.05) compared to those in OC. Similarly, the effective degradability (ED) of DM, CP, ADF and NDF in GHW were higher compared to OC (P < 0.05).
Key words: olive cake, tomato and cucumber wastes, in situ degradability