RESUMO Objetivou-se através deste estudo avaliar o efeito da adição de inoculantes sobre a estabilidade aeróbia, a composição químico-bromatológica, o padrão de fermentação e o perfil microbiológico da silagem de aveia branca (Avena sativa L.). O delineamento foi inteiramente casualizado, com três tratamentos e seis repetições. Os tratamentos foram três formas de ensilagem: aveia (A); aveia com inoculante bacteriano homofermentativo (AB); e aveia com inoculante bacteriano-enzimático (ABE). A estabilidade aeróbia foi de 9 dias para a silagem A e 14 dias para as silagens AB e ABE. O teor de carboidratos não fibrosos (CNF) diminuiu (16,67 para 14,05% MS), enquanto o teor de proteína bruta (PB) não foi alterado (média de 8,98% MS) no período de aerobiose em todas as silagens. A capacidade tampão (CT) diminuiu, enquanto o pH e a concentração de nitrogênio amoniacal (N-NH3) aumentaram no período de aerobiose em todas as silagens. Independente do período de aerobiose, a CT da silagem ABE foi maior do que a silagem A (29,67 vs. 24,80 meq/100 g MS). A contagem de bactérias ácido láticas na silagem AB (7,83 log UFC/g) foi maior do que nas silagens A e ABE (média de 5,24 log UFC/g). A silagem AB apresentou maior contagem de enterobactérias que a silagem ABE (2,49 vs. 0,76 log UFC/g). A inoculação com bactérias homofermentativas e com a enzima amilase na dose de 1×105 UFC/g não melhora a estabilidade aeróbia, a composição químico-bromatológica, o padrão de fermentação e o perfil microbiológico da silagem de aveia branca.

SUMMARY This study evaluated the addition of inoculants on the aerobic stability, nutritional value, and fermentation and microbiological profiles of white oat silages (Avena sativa L.). The trial was carried out in a completely randomized design with three treatments and six replicates. The treatments consisted of three ensiling approaches: oat (O); oat with homofermentative bacterial inoculant (OB); and oat with bacterial-enzymatic inoculant (OBE). The aerobic stability was 9 days for silage O and 14 days for silages OB and OBE. The non-fiber carbohydrates (NFC) decreased (16.67 to 14.05% DM) and the crude protein (CP) did not change (mean of 8.98% DM) during the aerobic exposure in all silages. The buffering capacity (BC) decreased, while pH and the ammonia nitrogen (NH3-N) increased during the aerobic exposure in all silages. Independent from the aerobic exposure period, BC of OBE silage was higher than O silage (29.67 vs. 24.80 meq/100 g DM). Lactic acid bacteria count in OB silage (7.83 log CFU/g) was higher than in O and OBE silages (5.24 log CFU/g, on average). Also, the OB silage showed high enterobacteria count compared to OBE silage (2.49 vs. 0.76 log CFU/g). The inoculation with Lactobacillus plantarum, Pediococcus acidilactici and amylase enzyme at the dose of 1×105 CFU/g does not improve the aerobic stability, nutritional value and the fermentation and microbiological profiles of oat silages.

Avaliou-se o desempenho e as características de carcaça de tourinhos mestiços confinados, alimentados com dieta contendo diferentes níveis de silagem de bagaço de laranja (0, 20, 40 ou 60%) substituindo a silagem de sorgo (% da matéria seca). Foram utilizados 36 animais distribuídos em baias individuais, em um delineamento inteiramente casualizado com nove repetições. A ingestão de matéria seca (IMS) apresentou incremento quadrático (P<0,01) em função dos níveis de silagem de bagaço de laranja na dieta. O ganho médio diário (GMD) também teve comportamento quadrático (P<0,01) em função do incremento da silagem de bagaço de laranja, estimando-se que o nível que permite máximo GMD é de 24,50%. Entretanto, ao se comparar as médias de GMD observou-se que a dieta com 20% de silagem de bagaço de laranja não diferiu das dietas com silagem de sorgo exclusiva e 40% de silagem de bagaço. A conversão alimentar não foi afetada pelas dietas (P>0,05), apresentando valor médio de 6,52. As características de carcaça não sofreram alterações (P>0,05) em função dos tratamentos. Foram observados valores médios de 298,37 kg; 13,50; 135,14 cm; 26,35 cm; 72,17 cm²; 5,26 mm; 5,81; 64,54%; 21,05%; 15,09%, para peso de carcaça quente, conformação, comprimento de carcaça, espessura de coxão, área de olho de lombo, espessura de gordura subcutânea, marmoreio e porcentagens de músculo, gordura e osso, respectivamente. A silagem de bagaço de laranja pode substituir a silagem de sorgo em até 40% da matéria seca, mas o nível de 24,5% é o que proporcionou máximo desempenho dos animais.

The study was conducted to evaluate the performance and carcass characteristics of crossbred young bulls in feedlot, fed rations with different levels of orange peel silage (0; 20; 40 or 60%) replacing the sorghum silage (% of dry matter). Thirty-six animals were allotted to individual pens, in a completely randomized design, with four treatments and nine replicates. The dry matter intake (DMI) showed a quadratic increase according to the level of orange peel silage in the diet. Average daily gain (ADG) was also quadratic behavior due to the increase of orange peel silage. It is estimated that level that allows maximum ADG is 24.50%. However, the ADG of the animals receiving diets with 20% of orange peel silage did not differ from those receiving sorghum silage or 40% of orange peel silage. The feed conversion ratio was not significantly affected (P>0.05) by treatments, with an average value of 6.52. Carcass characteristics were not altered (P>0.05) by treatments. Average values of 298.37 kg; 13.50; 135.14 cm; 26.35 cm; 72.17 cm²; 5.26 mm; 5.81; 64.54%; 21.05%; 15.09%, were observed for hot carcass weight, carcass conformation, carcass length, cushion thickness, rib eye area, subcutaneous fat thickness, marbling, and muscle, fat and bone yield, respectively. Orange peel silage can replace up to 40% of sorghum silage dry matter, with the same daily gain and without affecting carcass characteristics.

Biomass partitioning in forages is highly variable during plant development and with the rate of nutrient supply. This study was carried out with the objective to evaluate the tillering pattern and biomass partitioning of Mombasa grass (Megathyrsus maximus cv. Mombaça) subjected to rates of nitrogen (N) during regrowth. The treatments consisted of three weekly rates of N: control (without N supply), 25 and 50 mg dm-3 of N, which were evaluated by 1, 2, 4, 8, 16 and 32 days after defoliation. The design was of completely randomized blocks in a 3 × 6 factorial arrangement with three replicates. The number of tillers was measured and harvesting and weighting of the following morphological components were performed: leaf (leaf blades), pseudostem, stem base and root. Interaction between N rates and regrowth times was found for all variables analyzed. The N supply increased the number and weight of tiller (up to 117.3 and 167.6%, respectively), as well as the shoot dry matter yield of Mombasa grass. That effect was most significant particularly at 32 days of regrowth. Among the treatments receiving N supply, the highest N rate was more significant to leaf and shoot yield only after 6-11 days of regrowth. High N supply must be applied to Mombasa grass only after that time and the biomass harvested between 24-28 days of regrowth.