Crude protein contents in the concentrate ration and levels of supplementation for dairy cows grazing on brachiaria grass cv. Marandu during the dry season

It was evaluated the response of 40 Holstein/Zebu crossbred cows grazing on Brachiaria brizantha pasture to supplementation with concentrates containing different contents of crude protein. In addition to the pasture, 5.0 kg of sugar cane per animal was supplied daily. For control, it was used 200 g mineral supplement with 10% of phosphorous exclusively. Three concentrates containing 50.0; 28.6 and 20.0% of crude protein in natural matter, supplied at the quantities of 2.0; 3.5 and 5.0 kg/cow/day were compared. A randomized blocks design with 10 replicates was utilized. The supplements were given in two daily portions, after milking, in individual pens. After milking and morning supplementation, the forty cows were kept on pasture until the afternoon milking. At every 21 days after calving, until day 84, evaluations on milk productions, body weight and body condition score were made. The greatest milk production occurred 63 days after calving, when 3.5 kg of concentrate was supplied. As productive response, it was obtained values of 1.04; 1.20; and 0.63 kg of milk per kg of concentrate, respectively, for supply of 2.0; 3.5 and 5.0 kg regarded to the control. The animals in the control group had greater loss of body weight and body condition score, whereas there were no other differences among the other animals.