Desempenho de bovinos de corte em pastejo intermitente de Capim-Piatã (Urochloa brizantha cv. Piatã) manejado com base na altura do pasto, recebendo três estratégias de suplementação durante o período chuvoso

Abstract

The objective this study was to evaluate three supplementation strategies on yield characteristics of the pasture and its reflection in animal production. Was also evaluated the effect of supplementation strategies in feeding behavior of grazing cattle. The experiment was conducted at the Federal University of Tocantins, in the School of Medicine and Animal Science Veterinary and Animal husbandry – University Campus of Araguaína-TO. 18 beef cattle were used, males, with initial weight of 291 kg. The animals were kept in 4.8 ha of Piata grass (Urochloa brizantha cv. Piata), from January to May 2014. The pasture was divided into 24 plots of 0.2 hectares, managed under intermittent grazing with period variable rest being applied 60 kg/ha P2O5 at baseline and 50 kg/ha of NK each grazing cycle. The control treatment of animals received mineral supplementation at will, and the animals of energy treatments (ES) and protein-energy (PES) received 2g daily supplement for each kilogram of body weight. The average daily gain (ADG) was higher for the animals supplemented with SPE and SE in relation to MS, and of 1,097; 0.974 and 0.831 kg/animal/day, respectively. Highest total weight gain and by area and increased stocking rate was observed for the PES and ES strategies. The stocking rate was 4.78; 4.56 and 3.84 AU / ha, to the strategies of PES, SE and MS, respectively. The additional weight gain of the animals receiving PES and ES was 0.266 and 0.143 kg / animal / day, respectively, compared to MS. Due to the supplementation, grazing behavior has changed. The grazing time (PT), rumination (TR) and other activities (OA) were modified by supplementation strategies, and observed higher PR and lower TR and OA in the output condition, with average TP 105.56 minutes more and TR and AO 53.33 and 52.22 minutes less with respect to the input condition, regardless of supplementation strategy. A more meals with less time per meal was found in a condition of entry over the output averaged nine meals with an average time of 48.32 minutes. The highest rate of TB-bits (bits / second) was observed in a condition of entry, with an average of 41.84 bits / second, but the total number of output bits was higher in condition, with an average of value 9 20287.98 bits. Due to increased TB, the number of bits and the time per feeding station (s) were higher in the input condition, with an average of 9.70 bits with time of 13.84 seconds per feeding station. Due to the MMaller amount of forage in the condition close to the end of the busy period, the animals increases the total number of feeding stations, and consequently cover a greater area looking for grazing favorable sites. The strategic supplementation of grazing cattle is an economically viable alternative for growing in the rainy season and the choice supplementation strategy must take into account the objectives to be achieved, the quality of available forage and the desired economic results.