This study evaluated peanut cake as a replacement for soybean meal in the diet of steers. We used five castrated Holstein × Zebu steers, fistulated, with average live weight 550 kg, in a 5 × 5 Latin square design. The diets were composed of Tifton hay and ground corn with peanut cake (0, 25, 50, 75, and 100 %) as a replacement for soybean meal in the concentrate. Intake (kg/day) of dry matter, neutral detergent fiber, and crude protein were not affected by peanut cake, but ether extract intake increased linearly with the level of peanut cake in the diet. The digestibility of dry matter showed a quadratic effect, with a calculated maximum regression level of 56 % at 37 % replacement. There was no effect of the level of peanut cake on metabolizable energy intake and net energy, ammonia nitrogen, rumen pH, plasma urea, and glucose concentrations. We recommend replacing soybean meal in the concentrate with up to 40 % peanut cake.
Keywords: Blood urea nitrogen; Byproducts; Energy; N-NH3.