Suchergebnisse

This study aimed to evaluate the effect of cutting height and harvest time on forage yield and quality in elephant grass (Pennisetum purpureum Schum.) cv. Pioneiro. Experimental plots were arranged in a randomized block split-plot design. The treatments consisted of four residual heights (30, 40, 50, and 60 cm)and three successive harvest times (January, March, and May 2011). There was a significant interaction between residual height and harvest time for the proportion of stems (P<0.05) and leaves (P<0.01) in the forage. A similar result was observed for fresh (P<0.01) and dry (P<0.01) forage yield at the first and third harvests. There was a quadratic relationship between dry forage yield and residual height, with a maximum yield of5738 kg ha-1ataresidual height of 50.17 cm in the second harvest. The increase in residual height from 30 to 60 cm, regardless of harvest time, reduced neutral detergent fiber (NDF)and acid detergent fiber (ADF) and increased crude protein content. Forage yield and quality were highest at 40-50 cm residual heights.

We aimed to evaluate nutritional quality, fermentation profile, aerobic stability, and dry matter losses in corn (Zea mays) and wheat (Triticum aestivum 'BRS Umbu') silages. Treatments included uninoculated and inoculated (Lactobacillus plantarum and Pediococcus acidilactici, 1.0 × 105 UFC g-1) wheat silage, corn silage from a conventional hybrid and a transgenic hybrid. Nutritional quality and fermentation profile variables were tested in a completely randomized design. Means were compared using Tukey's test at 5% significance. An aerobic stability trial was conducted in a factorial design with two silages (wheat × inoculated wheat; conventional hybrid corn × transgenic hybrid corn) and two temperatures (ambient temperature × controlled temperature at 24°C). Data were submitted to ANOVA and means were analyzed by the F test at 5% probability. Inoculation of wheat silage increased dry matter, organic matter, and total carbohydrates, but reduced crude protein by a dilution effect. Regarding the fermentation profile, inoculation reduced acetic acid and butyric acid content, whereas it increased propionic acid in wheat silage. Bt corn hybrid silage showed higher dry matter and lower neutral detergent fiber, whereas transgenic corn silage showed lower content of acetic acid, propionic acid, alcohol, and ammonia. Conversely, Bt hybrid silage showed higher butyric acid. Transgenic corn silage showed higher temperature than the conventional hybrid silage during aerobic exposure. Inoculated wheat silage experienced larger deterioration and dry matter losses during the aerobic stability trial. Temperature control worsened aerobic stability in all treatments, increasing dry matter losses and heating.

Winter cereals are mainly used for human and animal nutrition and several studies are now exploring their potential as conserved forage (hay and silage). Among the winter cereal species available for cultivation in the south of Brazil, which is major winter cereals producer in the country, the wheat cv. BRS Umbu has attracted special attention. However, few studies have investigated the potential of this cultivar for silage production. The aim of this study was to evaluate the production and quality of silage from the dual-purpose wheat, BRS Umbu, subjected to different cut managements treatments: T1 - without cut (control), T2 - one cut and T3 - two cuts. Each plot represented an experimental unit in a randomized block design, with 5 replicates per treatment. Two representative samples were collected from each plot to determine morphological segmentation (stem, leaf and ear) and dry matter (DM) content of the whole plant and its morphological components. At the time of opening of the silos, food chemical analysis and pH determination were performed. Forage mass production decreased by 26.88% and 67.82%, respectively, with one and two cuts, compared to control. The DM content of the ensiled plant was 49.9 g kg-1 for the control, 54.7 g kg-1 with one cut and 63.2 g kg-1 with two cuts, at the time of ensiling. Management cuts changed the morphological components of the plants, with a lower proportion of stem (28%) in plants subjected to two cuts. The control treatment showed fewer leaves in ensiled plant (9.6%) and intermediate amount of stalk (52.8%), and was significantly different (p < 0.05) to treatment of a cut. Regarding feed chemistry evaluations, no significant difference (p > 0.05) was observed for mineral matter (MM), crude protein (CP) and hemicellulose (HEM) between the different cutting regimens. However, neutral detergent fiber (NDF) and acid detergent fiber (ADF) decreased (p < 0.05) as the number of cuts increased. The control treatment showed higher NDF and ADF content (563.2 and 357.9 g kg-1 DM, respectively) and lower amount of total digestible nutrients (TDN) and net energy of lactation (NEL). However, the estimated milk production (EMP) was superior for this treatment (22,447 l ha-1), demonstrating the high impact of reduced forage mass production with increased number of cuts.