Torta de girassol em suplementos múltiplos para bovinos em pastejo no período seco do ano

Abstract

Two experiments were conducted simultaneously in the beef cattle industry of Experimental Farm of Federal University of Mato Grosso, in order to evaluate the performance and production costs, as well as nutritional parameters in beef steers kept growing phase grazing Brachiaria brizantha cv. Marandu during the drought. In first experiment aimed to evaluate the inclusion levels of sunflower cake as protein source to replace soybean meal in formulation of multiple supplements for cattle grazing during the dry season on the performance and economic viability. We used 20 bulls, Nelore, non-castrated, with age and average initial weights of 20 months and 330 kg, distributed in four paddocks of 1.6 ha each, consisting of Brachiaria brizantha cv. Marandu. The experiment consisted of three experimental periods of 28 days each. The strategy adopted was the inclusion of sunflower cake in increasing levels of zero, 270, 540 g / kg of supplement, and a mixture composed only of mineral salt ad libitum (control). Supplements were formulated to be isonitrogenous (25% CP) and provided the amount of 1.5 kg / animal / day. The availability of total dry matter and digestible pontecialmente were 2248 and 1591 kg DM / ha respectively. The experiment was structured in a completely randomized design. Significant effect was observed (P <0.10) levels of inclusion of sunflower cake in relation to supplement control over the average daily gain (ADG). However, animals supplemented with zero g / kg sunflower cake had higher ADG (0.650 kg) compared to cattle supplemented with 270, 540 g / kg and that SAL had ADG of 0.558 kg, 0.521 kg and 0.161 kg, respectively. Economically, the inclusion of sunflower cake up to 100% replacement of soybean meal did not affect the financial return, standing out as a viable source of protein for cattle feed in the growing phase. In the second experiment aimed to evaluate the effect of inclusion levels of sunflower cake as protein source to replace soybean meal in multiple supplements for cattle grazing during the dry season on the nutritional parameters. Five steers were used, Nellore, non-castrated, with age and average initial weights of 20 months and 354.7 kg, respectively, divided into five paddocks of 0.25 ha each, consisting of Brachiaria brizantha cv. Marandu. The experiment was divided into 5 x 5 Latin square, composed of five experimental periods of 15 days each and five animals. The strategy adopted was the inclusion of sunflower cake in increasing levels of zero, 270, 406, 540 g / kg supplement and mineral supplement composed only by the will provided in the trough (control). Supplements were formulated to be isonitrogenous (25% CP) and provided 12 amount of 1.5 kg / animal / day of natural material. The availability of total dry matter and digestible pontecialmente were 3,120 and 2,379 kg DM / ha respectively. Effect was observed (P <0.10) levels of inclusion of sunflower cake compared to the control of supplement DM intake and BP. There was no effect of supplements on rumen pH (P> 0.10). There were statistically significant for concentrations of NH3-N for the time 4 hours after supplementation. We conclude that the inclusion of sunflower cake in the formulation of the supplements did not interfere with nutritional parameters can replace soybean meal in up to 100% without affect consumption of animals, this level of supplementation.