ABSTRACTThe objective of this study was to evaluate the production practices and use of corn silage in dairy farms in Southern Brazil, and to evaluate their impact on the nutritional quality and occurrence of mycotoxins. The data were collected by application of questionnaires among the producers, and by analysis of silage samples. The variables were subjected to factorial analysis of data reduction through the principal components method, thus obtaining 84.12% of the variance associated with the location, corn hybrid, crop production management, and inoculant used, characterizing the farms into four distinct groups. In farms from Paraná, the silage production technologies were more associated with implantation and crop management processes, and investment in equipment related to ensilage/silo feed-out was less frequent. Farms of Rio Grande do Sul showed high adoption of outsourced services, self-propelled machines, bunker silos, double-sided plastic film, and inoculant to control aerobic deterioration, and the silages showed higher levels of propionic acid (7.95 g/kg DM), and lower concentrations of aflatoxins (7.7 ppb) and total mycotoxins (26.58 ppb). The farms evaluated in Southern Brazil have good production efficiency and corn silages with excellent quality, regardless of their production characteristics.

Objetivou-se avaliar o efeito do uso de aditivo microbiano e de uréia na composição química, digestibilidade in vitro, no desaparecimento ruminal, e na estabilidade aeróbia de silagens de grãos úmidos de milho com adição de soja crua. Um segundo ensaio foi conduzido com o objetivo de avaliar a substituição do concentrado comercial por silagem de grãos de milho com adição de 20% de soja crua na produção e composição do leite de vacas holandesas. Para a avaliação das silagens foram feitos mini silos de pvc arranjados em delineamento inteiramente casualizado com três tratamentos (silagem de grãos úmidos de milho + 20% de soja crua; silagem de grãos úmidos de milho + 20% de soja crua + inoculante microbiano e silagem de grãos úmidos de milho + 20% de soja crua + 1,4% de ureia) e quatro repetições. As silagens apresentaram-se estáveis no período de 96 horas, com perdas de matéria seca de 3,55, 3,32 e 4,39 para silagens sem aditivos, com a adição de inoculante microbiano e com uréia respectivamente. A adição de uréia diminuiu a taxa de degradação ruminal das silagens de grãos úmidos de milho com adição de soja. Para a avaliação da produção e composição do leite foram utilizadas 20 vacas leiteiras arranjadas em delineamento inteiramente casualizado, com dois tratamentos e dez repetições. Verificouse que a silagem de grãos de milho com adição de grãos de soja pode ser usada na alimentação de vacas em lactação sem impacto sobre a produção e composição química do leite, mantendo os níveis de produção.

This study aimed to evaluate the effect of using microbial additive and urea on in vitro digestibility, in ruminal disappearance, and aerobic stability of moisture corn silage with the addition of raw soybeans. The experiment was conducted in a completely randomized design with three treatments (moisture corn grain silage + 20% of raw soybeans, moisture corn silage + 20% of raw soybean + microbial inoculant and moisture corn silage + 20% of raw soybean + 1.4% of urea) and four replications. Silages showed good aerobic stability, within the period of 96 hours, with few losses of dry matter and no consistent variations in the chemical composition. The Urea addition decreased the rate of ruminal degradation of the moisture corn silage with the addition of soybean. A second trial was conducted to evaluate the replacement of commercial concentrate by moisture corn silage with the addition of 20% of crude soybean, 20 dairy cows were used and arranged in a completely randomized design with two treatments and ten replicates. It was found that the moisture corn silage with added soybeans can be used in diets for lactating cows, in replacement of the commercial concentrate, with no impact on the production and chemical composition of the milk, maintaining production levels.