Uso do Refinazil como concentrado alternativo em dietas de vacas em lactação

Abstract

The objective of the following study was to evaluate the effects of replacing 28 conventional concentrate (based on soybean bran, wheat bran and corn) with refinazil in the 29 diet of lactating cows, on the consumption and digestibility of nutrients and the production and 30 composition of milk. The experiment was conducted at the Experimental Station of the 31 Pernambuco Agronomic Institute (IPA) located in the city of São Bento do Una-PE. Eight 32 Holstein cows with an average live weight of 503 +- 31.4 kg, with an average milk production 33 of 17.3 +- 2.3 kg of milk/day and 90 days in lactation. The animals were distributed in two 4x4 34 Latin Squares, with four animals, four treatments and four experimental periods. Each 35 experimental period lasted 21 days, with 14 days for adapting the animals to the diets and seven 36 days for collecting data and samples. The consumption of dry matter (DM) (minimum 37 consumption of 14.05 kg with 51.7% replacement) and organic matter (OM) (minimum 38 consumption of 12.46 kg with 46.17% replacement) showed quadratic behavior, the intake of 39 digestible dry matter (DDM), digestible organic matter (DOM), non-fibrous carbohydrate 40 (NFC) and total digestible nutrients (TDN) decreased linearly with replacement. The 41 consumption of corrected neutral detergent fiber (NDF) increased linearly, while the crude 42 protein (CP) content was not influenced by substitution. Regarding digestibility, only CP 43 decreased linearly and NDFcp showed a quadratic behavior (maximum digestibility of 485.7 44 g/kg DM with 32.88% replacement). Milk production without (19.11-15.91 Liters/day) and 45 with correction (19.82-16.8 Liters/day) decreased linearly. While the fat content (3.8%), crude 46 protein (3.2%), lactose (4.8%) and total solids (12.5%) were not changed by the substitution. It 47 is concluded that it is not recommended to replace conventional concentrate, based on corn, 48 soybean bran and wheat bran (24% CP) with Refinazil in diets for cows with an average 49 production of 20 kg of milk/day.