ABSTRACT: This study was undertaken to evaluate the effects of dietary calcium levels and supplementation with organic trace minerals selenium, copper, iron, zinc and manganese on performance, tissue deposition and litter mineral concentration. A total of 2,496 one-day-old male Cobb 500 broilers were randomly assigned to a 3 × 4 factorial experimental design with three levels of dietary Ca [8, 10 and 12 g kg–1, while maintaining the same Ca:nPP (non-phytate phosphorus) ratio (2:1)] and four levels of micromineral supplementation (0.62, 0.72, 0.82 and 0.92 g kg–1). There was a total of 12 treatments, with eight replicates of 26 birds per pen. Micromineral supplementation (MS) was achieved by adding different levels of the product Bioplex TR Se® and Ca supplementation was achieved by adding increasing levels of limestone and dicalcium phosphate. An interaction between Ca and MS levels was observed (p < 0.05) for the parameters of performance, liver Cu concentration, breast Se and Cu concentrations and litter Se, Mn and Zn concentrations. No interactions were observed (p > 0.05) for Ca, P or ash concentrations in the tibia, which were influenced only by dietary Ca levels (p < 0.05). The Ca level of 10 g kg–1 promoted higher Ca and P concentration in the tibia and lower micromineral excretion in the litter. The combination of MS level of 0.82 g kg–1 with Ca level of 10 g kg–1 led to the best BWG response. The supplementation conditions that led to higher micromineral levels in the liver and breast varied for each mineral.

The objective of this study was to determine the deferment period and the most adequate initial sward height of Brachiaria brizantha cv. Piatã for deferment in the region of Viçosa, Minas Gerais. For so, the following characteristics were evaluated: masses and bulk density of forage and its morphological components, light interception by the sward, leaf area index, leaf angle, sward and extended tiller height and falling index of the deferred piatã grass. The three deferment periods assessed (65, 85 and 105 days) were randomized to the plots and the three sward heights (20, 30 and 40 cm), randomized in the subplots. The experimental design was of completely randomized blocks, with three replicates, in a subdivided plots arrangement. Masses of forage, green stem and dead tissue were higher in the piatã grass managed with deferment period of 105 days. The mass of green leaf blade was higher in the piatã grass deferred with 20 cm height associated to the deferment period of 85 days, which had, as consequence, greater bulk density of green leaf blade. The interception of light by the sward was greater in the piatã grass kept longer in deferment associated with the higher leaf area index, regardless of its initial height. The heights of the sward and extended tillers were greater in the piatã grass under periods of 85 and 105 days of deferment; however, the falling index was not affected by the factors studied. In the region of Viçosa, Minas Gerais, B. brizantha cv. Piatã fertilized with 75 kg/ha nitrogen and deferred with initial height of 20 cm and for a period of 85 days, from mid April, has adequate productivity and structure for animal production.

The objective of this study was to evaluate the mass of the forage and of the morphological components, and the sward structure in Piata palisadegrass (Brachiaria brizantha cv. Piata) deferred in function of different initial heights and nitrogen levels. Two levels of nitrogen (75 and 150 kg/ha) and one control without fertilization associated to three initial deferring heights (20, 30, and 40 cm) were evaluated. The design was of completely randomized blocks with three replications in a subdivided plot scheme. A raise in the initial deferment height and in the fertilization elevated the sward and extended tiller heights, the leaf area index, and the light interception by the sward. The piata palisadegrass deferred with an initial height of 40 cm presented a higher forage mass with lower percentage of leaf blades, and higher stem and dead tissue quantity. Additionally, this management strategy resulted in lower bulk density of leaf blade and in higher bulk densities of stems and dead tissue. The utilization of 150 kg/ha of nitrogen raised the production and the bulk density of deferred piata palisadegrass forage and increased production and bulk density of leaves and stems. In the region of Viçosa, Minas Gerais, the piata palisadegrass deferred with an initial height of 30 cm and fertilized with 75 kg/ha of nitrogen in the beginning of the fall presents adequate mass and structure to animal production in the winter.