Qualidade da silagem de trigo produzida sob níveis de adubação nitrogenada em dois estádios fenológicos

The objective was to evaluate the effects of two content levels of nitrogen dressing (88 kg ha-1 and 148 kg ha-1) in the wheat silage production of BRS Umbu harvested during two phenological stages (pre-flowering and floury grain). The production of fresh dry phytomass as well as morphological and chemical composition of silages were evaluated. This study used a randomized blocks design with a 2x2 factorial structure, with two content levels of nitrogen dressing and at two different harvest stages, with four replications. There was interaction (p<0.05) between levels of nitrogen dressing and phenological harvest stages for neutral detergent fiber (NDF) and acid detergent fiber (ADF) of silage. The wheat with a level of 88 kg N ha-1 and harvested at the phenological stage of floury grain had the lowest NDF (57.52%) and ADF (34.62%), compared to the cultivation with content of 148 kg N ha-1. Harvest during pre-flowering promoted higher production of fresh phytomass (25.178 to 20.646 kg ha-1); however, there was higher production of dry matter in the floury grain stage (9.792 to 4.808 kg ha-1). Crude protein was higher in silage harvested during pre-flowering compared to the floury grain stage, with 11.55% and 6.96%, respectively. Based on joint analysis of the results, wheat silage harvested at the stage of floury grain and with nitrogen dressing of 88 kg ha-1 had the best production and nutritional outcomes.O objetivo do trabalho foi avaliar os efeitos de dois níveis de adubação nitrogenada em cobertura (88 kg ha-1 e 148 kg ha-1) na produção de silagem do trigo cultivar BRS Umbu, colhido em dois estádios fenológicos (pré-florescimento e grão farináceo). Foram avaliadas as produções de fitomassa fresca e seca, composição morfológica e bromatológica das silagens. O delineamento experimental foi de blocos ao acaso em esquema fatorial 2x2, sendo dois níveis de adubação nitrogenada em cobertura e dois estádios de colheita, com quatro repetições. Houve interação (p<0,05) entre os níveis de adubação nitrogenada e os estádios fenológicos de colheita para fibra em detergente neutro (FDN) e fibra em detergente ácido (FDA) da silagem. O trigo cultivado com nível de 88 kg N ha-1 e colhido no estádio fenológico grão farináceo apresentou os menores teores de FDN (57,52%) e FDA (34,62%) comparativamente ao cultivo com nível de 148 kg N ha-1 no mesmo estádio de colheita. A colheita em pré-florescimento promoveu maior produção de fitomassa fresca (25.178 contra 20.646 kg ha-1), entretanto, houve maior produção de fitomassa seca no estádio de grão farináceo (9.792 contra 4.808 kg ha-1). Os teores de proteína bruta foram maiores na silagem colhida em estádio de pré-florescimento quando comparada a de grão farináceo, com 11,55 e 6,96%, respectivamente. Na avaliação conjunta dos resultados, é possível concluir que a silagem de trigo colhida em estádio de grão farináceo e com adubação nitrogenada de 88 kg ha-1 possibilitou os melhores resultados produtivos e nutricionais

Nutritional characteristics and losses on fermentation of corn silage, harvested in different reproductive stages with different grain processing

O experimento foi conduzido no Núcleo de Produção Animal (NUPRAN) da Universidade Estadual do Centro Oeste (UNICENTRO), com o objetivo de avaliar o efeito da colheita da planta de milho em diferentes estádios reprodutivos e com diferentes processamentos de grãos sobre as perdas e o valor nutritivo das silagens. Diferenças (P 0.05) results found for the R5 stage, which had an average loss of around 5.77%, demonstrating that silage harvested at R5 stage, allow greater dry matter recovery and hence greater savings for the farmer. Regarding the parameter of losses of crude protein, there were no significant differences for the effects of isolated or associated stages of harvesting and processing of grain in corn silage. Large differences can be perceived as the loss of neutral detergent fiber and loss of acid detergent fiber silage, justified by the increase in the levels of acid detergent fiber in the average share of 22.96% in the silage harvested at stage R3 and reduction in their concentration with an average of 4.60% for the R5 stage. No significant differences were observed (P <0.05) for the particle size as the different treatments, only significance being observed as the participation of whole grains in bulk, this ranging on average from 2.59% to 10.27% dry matter, respectively for stage R3 and R4-R5. In general, silage maize plant reproductive stage R5 provided smaller losses nutritious silage storage and greater accumulation of grains in bulk when compared to R3 stage