Suplementos múltiplos em estratégias de produção intensiva de bovinos a pasto

Abstract

Three experiments were conducted in the sector of Cattle Cutting the Experimental Farm of the Federal University of Mato Grosso, in the municipality of Santo Antônio do Leverger - Mato Grosso, to evaluate the delivery of multiple levels of supplements on nutritional parameters, yield performance, viability economic Nellore heifers recreated on Brachiaria brizantha. Marandu during the dry season; and evaluate the delivery of replacement levels of corn for glycerin in multiple supplements on performance and economic viability of Nellore steers on pasture during the dry season. In experiment 1 were used 20 Nellore heifers, with age and initial weight average of 22 months and 328.45 kg, respectively, which evaluated the following supplements: control (mineral supplement) and supplementation levels of 2, 4 and 6 kg/animal/day, composing the following percentages of average body weight (ABW): 0.55, 1.11 and 1.66%, respectively. The completely randomized design with four replications and five supplements. The average daily weight gain (ADG) presented a quadratic (P <0.0001) according to the level of supply of supplements. The strategy of supply of 0.55% PCM provided the best economic return and productive response. In experiment 2 were used 5 Nellore heifers, average weight and aged 22 months and 344.00 ± 21.10 kg, respectively, which evaluated the same supplements of experiment 1 beyond the level of 8 kg / animal / day (2.22% BW). The design was a Latin square design with five replications and five supplements. Intakes of total dry matter, crude protein (CP) and total digestible nutrients, and total apparent digestibility of dry matter, crude protein, total carbohydrates and no fiber increased linearly (P <0.0001) and dry matter intake of forage decreased (P <0.0001) with supplementation levels. Supplementation strategies promoted reduction on ruminal pH (P = 0.0343) and increased concentration of ruminal ammonia nitrogen (NH3-N) (P = 0.0004) before the supply of supplements, and after that the NH3-N presented quadratic behavior (P = 0.0023). Providing high levels of multiple supplement provides better nutritional intakes for cattle on systems with low supply of pasture in the dry season. In experiment 3 were used 40 Nellore steers with initial body weight of 203, 12 ± 20.10 kg and average initial age of 12 months, divided into eight paddocks of 1.6 ha each. The completely randomized design with five replicates and eight supplements. We evaluated supplements with levels of partial replacement of corn per glycerin: 0% (G0), 10% (G10) 20% (G20); 30% (G30), 40% (G40), 50% (G50) and 60 % (G60) supplied in the amount of 1 kg / animal / day as fed, and control (mineral supplement) ad libitum (MS). The average daily gain (ADG) was higher (P <0.10) for animals receiving supplements G30 (0.609 kg), G 40 (0.588 kg) and G60 (0.611 kg) in relation to supplements G0 (0.546 kg), G10 (0.509 kg), G50 (0.561 kg) and MS (0.223 kg). There were differences (P <0.10) in ADG for supplemented animals when compared to MS. The supplemented animals showed higher ADG (P <0.10) compared to MS. The different levels gave positive financial return. It is concluded that the supply of multiple supplements replacing the corn by glycerol in production systems of steers in the dry period provides higher productive performance levels of 30, 40 and 60% and positive financial return to levels of 60% of substitution, demonstrating thus its potential use for intensive systems of beef production on pasture. The supply of multiple supplements for cattle grazing during the dry season provides performance and positive financial return, demonstrating thus its potential use in intensive production systems beef on pasture.