Desempenho de bovinos de corte no pasto suplementados com misturas múltiplas contendo uréia e amiréia Performance of grazing beef cattle supplemented with multiple mixtures containing urea and amireia

O presente trabalho foi realizado com o objetivo de avaliar o real potencial da amiréia 150S comparada com mistura equivalente em uréia, milho moído e flor de enxofre, como ingredientes em misturas múltiplas para bovinos de corte no pasto. Foram utilizados 40 bezerros sem raça definida, com peso médio de 167 Kg, no período das águas, e 40 bezerros sem raça definida, com peso médio de 285 Kg, no período seco. Os tratamentos foram baseados na amiréia 150S e mistura equivalente em milho moído, uréia e flor de enxofre com núcleo mineral e sal, sendo esse em dois níveis para regular consumo. As misturas formuladas foram amiréia com 8,75% de sal (AM-8,75), uréia com 8,75% de sal (UR-8,75), amiréia com 17,50% de sal (UR-17,50) e uréia com 17,50% de sal (UR-17,50). O delineamento experimental utilizado foi em blocos casualizados com repetição dentro dos blocos experimentais. Avaliaram-se o desempenho e o consumo das misturas dos animais nas fases das águas e seca. Não foi encontrada diferença para ganho de peso (GP) e ganho de peso médio diário (GPMD) entre os tratamentos na fase das águas, na qual se pôde observar uma melhor qualidade da forragem nos piquetes. No período seco, quando a qualidade do capim foi inferior à do período das águas, houve diferença significativa para GP e GPMD, ou seja, observaram-se melhores desempenhos para os animais que receberam misturas com amiréia 150S do que para os animais que receberam misturas com uréia.<br>The present work was carried out with the objective to evaluate the real potential of the amireia 150S compared with equivalent mixture with urea, corn ground and sulfur flower as ingredients in multiple mixtures for grazing beef cattle. It was used 40 calves without defined breed with average weight of 167 Kg in the raining season and 40 calves without defined breed with average weight of 285 Kg in the dry season. The animals were distributed in paddocks of Brachiaria brizantha cv. Marandu and were separated by electrified fence and each paddock possessed covered hod and individual drinking fountain. The treatments were based in the amireia 150S and equivalent mixture with ground corn, urea and sulfur flower with mineral nucleus and salt being these two levels used to regulate consumption. The formulated mixtures were amireia with 8.75% of salt (AM - 8.75), urea with 8.75% of salt (UR - 8.75), amireia with 17.5% of salt (UR - 17.50) and urea with 17.5% of salt (UR - 17.50). The experimental design used was randomized blocks with repetition inside; the 40 animals of each phase were divided in 5 blocks in function of the initial weight and then they were allocated randomly in the 4 paddocks where the animals received the treatments at random. It was evaluated the performance and consumption of the mixtures offered to the animals in the raining and dry seasons. It was not found significant difference for weight gain (GP) and average daily weight gain (GPMD) among the treatments in the raining season in which a better quality of the forage can be observed in the paddocks. In the dry season where the grass quality was inferior when compared to that of the raining season there was significant difference for GP and GPMD in which was observed best performance for the animals who received mixtures with amireia 150S in relation to the animals that received mixtures with urea.