RESUMO
This study evaluated the total replacement of soybean meal with peanut cake in the concentrate supplement of lactating cows grazing. Eight crossbred 5/8 Holstein × 3/8 Zebu cows between the 45th and 60th day of lactation and 507 ± 35 kg BW were distributed in a 4 × 4 double Latin square design with four levels of peanut cake (0, 110, 220, and 330 g/kg of the dry matter-DM) as a replacement of soybean meal in the concentrate supplement. The intake of pasture, total (pasture + concentrate), crude protein (CP), neutral detergent fiber (NDF), total digestible nutrients, and digestibility of the DM, CP, ether extract (EE), and NDF was not affected by the replacement of soybean meal with peanut cake. However, the EE (P = 0.83) intake and non-fiber carbohydrate digestibility (P = 0.09) exhibited an increasing linear trend by the peanut cake inclusion. The NDF exhibited a decreasing linear trend (P = 0.07) as the level of peanut cake increased. Production, corrected production, and protein, fat, lactose, total solid, and non-fat solid composition concentrations in the cows' milk were not affected (P > 0.05) by the peanut cake inclusion. The protein/fat ratio exhibited an increasing linear trend (P = 0.082) by the peanut cake inclusion. Peanut cake can completely replace soybean meal in the concentrate mixture because it does not alter dry matter intake, production, and composition of milk, and in addition it can reduce the cost of feeding.