The effects of four levels of concentrate - LC (0, 1, 3 and 5 kg/cow/day) and two of crude protein - CP (11 and 13% crude protein in total dry matter) on the intake, digestibility and performance of milking cows were evaluated. Eight crossbred Holstein-Zebu cows with 520 ± 40 kg were distributed in an 8 × 8 Latin square in eight 10-day periods for evaluation of effects of treatment, animal and period. The experiment was conducted on elephant grass (Pennisetum purpureum, Schum) pasture in the rainy season and the concentrates consisted of corn meal, soybean meal, urea and mineral salt. The dry matter (DM) intake was not different among treatments, and the pasture intake tended to decrease with increase in LC. The intakes of CP and non fiber carbohydrates (NFC) increased as a function of increase in LC and CP in the diet, while the intakes of total digestible nutrients, NFC, neutral detergent fiber (NDF) and ether extract increased only with increases in LC. The digestibility coefficients (DC) of DM and NFC increased and decreased, respectively, with increase in LC; the DC of CP increased with LC and CP; and the DC of NDF increased with increase in CP in the diet. The milk production increased only with increased LC. The milk components were not affected by LC, but there was increase in the lactose and dry extract contents in the milk with increase in dietary CP. Cows on pasture during the wet season and producing 12 kg of milk/day can receive diets containing 11% CP and the response to concentrate supplementation is low, varying from 0.63 to 0.22 kg milk/kg of concentrate, compared with 2.2 kg/kg suggested by the NRC 2001 for dairy cattle.
energy; milk composition; nutrition; pasture; ration
