Processamento e ensilagem no valor nutritivo de grãos de milho para novilhos em confinamento

• Autor(a) principal: Silva, Marlon Richard Hilário da
• Data de Publicação: 2015
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Estadual de Maringá (RI-UEM)
• Texto Completo: http://repositorio.uem.br:8080/jspui/handle/1/1600
• topic: Silagem de grãos; Nutrição animal; Ruminantes; Bovinos de corte; Milho reidratado; Amido; Reidratação de grãos; Brasil.; Starch; Beef cattle; Young steers; Processing grain; Rehydrated grains; Grain silage; Brazil.; Ciências Agrárias; Zootecnia

The objective was to evaluate the effects of rehydration and ensiling of corn grain with two average particle sizes in order to elucidate the effects on the quality, dry matter recovery, production of organic acids, aerobic stability and pH under conditions of exposure to oxygen, in addition to response on performance, carcass characteristics and economic viability in termination of young bulls finished in feedlot. Experiment I - It has consisted in evaluating the effect of two physical processes through the dry corn milling, in two or six mm sieves generating two materials with geometric mean diameter of 0.60 and 1.85 mm, followed by rehydration with water from the ground grain and application of microbial inoculant, reconstituting the moisture until values close to 35%. The design was completely randomized with two treatments and six replicates. The treatments were defined - silage of corn grain finely ground and rehydrated (SCFR) and silage of corn grain ground and rehydrated (SCGR). Experimental silos were used (mini bags) up to 1000 g and silage wrapping in vacuum. The silos remained at room closed until ambient temperature at moment of opening, when the materials as stability and production of organic acids were analyzed. There was no effect on the dry matter recovery, however there was an excellent recovery rate, with values greater than 97% in both silages. There was influence of the particle size (p <0.05) on the fibrous portion (NDF and ADF), with lower values being observed in this manner for SCFR. The concentration of acetic and lactic acid was increased for SCFR, due to higher fermentability observed, without further amendments on pH, which was different only in the oxygen exposure phase, with values of 4.25 and 4.38 for SCFR and SCGR respectively. After opened both silages showed excellent aerobic stability above 120 hours, thus promoting minor theft activity and therefore minor losses of quality. Generally corn grain silages rehydrated showed improvements over the fermentation process and the stability, with benefits for SCFR with superiority over SCGR. Experiment II - This trial aimed to evaluate the effect of milling, rehydration and silage of corn grain on growth performance, carcass characteristics and economic viability in comparison with the dry corn grain in two different particle sizes in diet of beef cattle in termination. For that 40 crossed steers with initial average age of 13 months and initial weight of 374 kg were used. The design was completely randomized in a 2x2 factorial arrangement (two moisture contents and two corn sources) and tested the following treatments: dry corn grain finely ground (DCFG); dry corn grain ground (DCG); silage of corn grain finely grounded and rehydrated (SCFR) and silage of corn grain grounded and rehydrated (SCGR), accounting for 38% of the total diet also consisting of 50% corn silage and 12% concentrate. There was no effect of treatment, moisture content and processing (P>0.05) on the average daily gain (ADG) and final weight. There were differences on feed conversion (FC) and gain: feed rate (G:F) for young steers at treatments with silage of corn grain rehydrated (SCFR and SCGR). The dry matter intake was lower for treatments silage rehydrated corn, justifying this way the results obtained for FC and G:F. There is a view that the steers of treatments with inclusion of silage of grain rehydrated had similar ADG with inclusion of dry corn in the diet. The process used to obtain fine dry corn silage improved starch digestibility as well as decreased fecal starch. There was also increased NE maintenance and gain for finely processing and silage, compared to dry ground corn. For carcass characteristics differences (p<0.05) were observed for hot carcass weight, carcass yield in gain and weight gain of carcass, with highlights for treatments DCFG and SCGR, with better averages. The silage of corn grain grounded and rehydrated (SCGR) presented better economic viability, due to the productive performance and carcass merits, even the method of rehydration and silage being more expensive. The results suggest that silage of corn grain grounded and rehydrated (SCGR) can be used in termination for obtaining productive and economic increments.