Comparison of alfalfa and fenugreek (Trigonella foenum-graecum) silages supplemented with barley grain on performance of growing steers

To compare nutritive value of alfalfa and fenugreek silages for weaned back grounding feedlot steers, isonitrogenous diets of alfalfa or fenugreek sila ge, supplemented with three levels of steam-rolled barley (0, 15 and 30% DM ) were fed ad libitum to 60 steeps (initial weight of 237 +/- 18 kg). The s tudy was conducted in individual pens for 105 d using a 2 x 3 factorial exp eriment. Fenugreek was cut 17 wk after seeding while the alfalfa was cut at mid-bloom. Both fenugreek and alfalfa silages were prepared in plastic tub e silos after wilting to 38 and 35% DM, respectively. After ensiling for 40 d, silage tubes were opened and a feeding trial was conducted. Alfalfa and fenugreek silage contained similar levels of CP (18.0 and 17.2 %, respecti vely) while fenugreek silage contained a lower level of NDF (38.2%) than al falfa silage (40.4%). Dry matter intake (DMI) and average daily gain (ADG) of steers increased (P < 0.001) and feed efficiency (FE) improved linearly (P < 0.001) with increasing grain level in the diet. Dry matter intake (6.4 vs. 6.2 kg d(-1)), ADG (0.82 vs. 0.84 kg d(-1)), FE (8.1 vs. 7.8), total r umen volatile fatty acids (103.4 vs. 105.3 mM), rumen fluid pH (6.9 vs. 6.9 ) and rumen ammonia concentration (9.6 vs. 10.4 mg dL(-1)) in steers were s imilar for both alfalfa- and fenugreek-silage-based diets, respectively. Al though in vitro rate of gas production was different at 12.6 and 17.4% h(-1 ) for alfalfa and fenugreek diets, respectively, potential gas production a t the end of 72 h of fermentation was similar (21.6 vs. 22.3 mt 100 mg(-1) DM). The presence of steroidal saponins in fenugreek plants did not affect steer performance or hormonal status when fed as silage. Results from this study indicate that the nutritive value of fenugreek silage is comparable t o that of mid-bloom alfalfa silage, and that fenugreek, a high-DM yielding annual legume, has potential to be a valuable forage in feedlot diets.