Nutritive value of citrus pulp ensiled with wheat straw and urea, using in vitro and in vivo methods

Fresh citrus pulp (FCP) was mixed with wheat straw (WS) 90:10 and ensiled in three treatments 1) 0.0% urea, 2) 0.5% urea and 3) 1% urea, using 40 kg nylon bags. After three months of ensiling, silos were evaluated and sampled for chemical analysis and in vitro gas test. In vivo digestibility and intake of the silages were determined in sheep nutrition along with basal diet (Alfalfa hay+WS+barley ground). Dry matter (DM) ranged 19.32 to 21.15% and pH 3.59 to 3.74 in silages. Crude protein and NH3-N were increased (P<0.05) in silages contained urea. There were no significant differences between silages for gas production. The in vivo digestibility of DM, OM and NDF, and ME were similar between the basal diet and the experimental diets as well as the experimental silages. However, digestibility of CP was increased in silages contained 0.5 and 1% urea (P<0.05). An increasing trend was observed for DM intake where the animals received ad-libitum silages than the basal diet. Daily urine weight and urine pH was increased (P<0.05) when the animals fed 1% urea silage, comparison to the other diets but, ruminal pH was not affected by the treatments. Finally, it is concluded that ensiling of FCP plus WS to provide a mixture with optimum DM content may be an appropriate method of preserving and using of this by product in ruminant nutrition. In addition, deficiency of CP could be compensated by addition of proper amount of urea.