In vitro Evaluation of Alfalfa Substitution with Fenugreek (Trigonella foenum graegum) Hay in a High Concentrate Ration

This study was conducted to evaluate the possibility of alfalfa replacement with fenugreek hay for rumi-nants, using in vitro gas production parameters and some of rumen fermentation characteristics. For this propose, five different total mixed rations were formulated to meet nutrient requirements of 35 kg growing lambs with gradually replacement of alfalfa in control diet (T1) with different levels of fenugreek hay (25, 50, 75 and 100%, respectively T 2, T3, T4 and T5). In vitro gas production (mL/200 mg DM) was deter-mined at 2, 4, 6, 8, 12, 24, 48, 72 and 96 hours of incubation. Ammonia-N concentration (mg/dL) and pH of rumen liquor was determined immediately after removal. Gas production was increased with increasing levels of fenugreek (P < 0.05). Significant increases of gas production from insoluble fraction (b) were ob-served with increasing levels of fenugreek hay (P < 0.05). A same trend was observed for potential gas pro-duction (a+b, P < 0.05). Also, the constant rate of gas production (c) of T2, T3 and T4 were significantly higher than control, but the differences between T3, T4 and T5 were not significant. Replacement of fenu-greek at 25 and 75 percent significantly increased final pH compared to control (100% alfalfa) (P < 0.05), but the differences between T3, T5 and control and between T3, T4 and T5 were not significant. Short chain fatty acids production (mmol/200 mg DM) was significantly greater in treatments with 50% or more fenu-greek substitution (P < 0.05). Organic matter digestibility of treatments containing 50% or more fenugreek hay (T3, T4 and T5) were significantly higher than control (P < 0.05). Similarly, estimated metabolisable energy content of these treatments were higher than control (P < 0.05). According to these results, it can be concluded that fenugreek can provide highly valuable forage for ruminants with comparable feeding values with alfalfa, and alfalfa can be replaced completely in ration with fenugreek hay without any problem.