Rev Mex Cienc Pecu 2021;12(1):72-86
Material and methods Animals and treatments
The experiment was conducted on Fazenda Valeu Boi, located in the municipality of Encruzilhada – Bahia, between May 03 and August 22, 2016, 2016, and approved by the Ethics Committee on the Use of Animals (ECUA) under protocol nº. 104/2015 of April 15, 2015. Four crossbred Holstein x Zebu cows (blood level between ½ and ¾ H x Z blood) were used, at the third or fourth lactation order, with average milk production between 4,500 and 6,000 kg in the previous lactation, adjusted for 300 d of lactation, with a mean body weight of 548 ± 17 kg. Cows were also selected according to lactation days, between 80 and 120 d at the beginning of the experimental period. They were arranged in a 4 x 4 Latin square, consisting of four experimental periods, with 21 d each, for which the first 16 d corresponded for adaptation and the last 5 d for data collection. The licuri cake was purchased from Lipe Indústria de Sabão e Velas Ltda, Guanambi Bahia. Inclusion levels of the by-product in the total diet were 0.0, 5.5, 11.0 and 16.5 %, which corresponded to the replacement of 0.0, 25.0, 50.0 and 75.0 % of the crude protein of the total diet. The diets were formulated in an attempt to be isoenergetic and isoproteic, in order to contain sufficient nutrients for maintenance, body weight gain of 0.15 kg d-1 and production of 25 kg milk d-1, adjusted to 3.5 % of fat, according to the requirements table(5), and based on the chemical-bromatological composition data of sugarcane, corn, soybean meal and LC, previously analyzed before the beginning of the experimental period. The bulk source used was sugarcane (Saccharum officinarum), variety RB 72-454, treated with 1% urea-ammonium sulfate mixture (9:1), on a fresh matter basis. Table 1 shows the proportions of the ingredients in the concentrates and the ratio bulk source:concentrate, on a dry matter basis.
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