RESUMO: Avaliou-se a qualidade química e fermentativa de silagens de milho e sorgo enriquecidas com planta inteira de soja. Foram utilizadas as proporções de 75%, 50% e 25% da planta de soja na ensilagem de milho ou de sorgo. Com o acréscimo do nível de inclusão da planta inteira de soja houve aumento linear no teor de proteína da dieta na silagem de milho e sorgo, e aumento no teor de fibra em detergente ácido na silagem de milho, porém houve decréscimo no teor energético da silagem de milho e do teor de fibra em detergente neutro da silagem de sorgo. Não foram observadas diferenças nos níveis de inclusão da planta de soja na ensilagem de milho e sorgo quanto à digestibilidade in vitro da matéria seca e da matéria orgânica. A adição da planta inteira de soja aumentou o pH e a concentração de N-NH 3 das silagens de milho e sorgo, mas manteve o pH em níveis aceitáveis quando o nível de inclusão da planta de soja foi 50%. Sob o ponto de vista da composição química, a planta de soja pode ser adicionada em até 50% na ensilagem de milho e na ensilagem de sorgo, trazendo melhorias ao produto final.Palavras-chave: digestibilidade, gramínea, leguminosa, qualidade. CHEMICAL COMPOSITION OF CORN AND SORGHUM SILAGE WITH INCLUSION OF WHOLE-PLANT SOYBEANSABSTRACT: This study evaluated the chemical and fermentation quality of corn and sorghum silage enriched with whole-plant soybeans. Whole soybean proportions of 75%, 50% and 25% were used for ensiling corn or sorghum. The increasing inclusion levels of whole-plant soybeans resulted in a linear increase in the dietary protein content of corn and sorghum silage and in an increase in acid detergent fiber of corn silage, while a decrease was observed in the energy content of corn silage and in neutral detergent fiber content of sorghum silage. The in vitro dry matter and organic matter digestibility did not differ between soybean inclusion levels in corn or sorghum silage. The addition of whole-plant soybeans increased the pH and N-NH3 concentration of corn and sorghum silage, but maintained the pH at acceptable levels when the inclusion level of whole soybeans was 50%. With respect to chemical composition, whole soybeans can be added to corn and sorghum silage at a proportion of up to 50%, with improvements of the final product.

-The objectives of this study were to evaluate the effects of cultivation and hay making factors on chemical composition, protein fractionation, and digestibility in rice straw, as well as to identify the chemical fractions that contribute to the variation in its nutritional value for ruminants. Statistical procedures were performed in a model that included rice crop cycle, sowing season, baling season, soil classification, fertilizer application, and productivity (kg/ha) as fixed effects and the hay bale as random effect. Chemical composition, protein fractionation, and digestibility data were subjected to multivariate analyses including factor, cluster, and discriminant. Considering the cultivation and haymaking factors, development cycle, baling season, and grain production explained the most variation in the rice straw nutritional value. Straws derived from early maturing cultivars showed the lowest levels of neutral detergent fiber, acid detergent fiber, acid detergent insoluble nitrogen, and C nitrogen fraction in comparison with straw originating from mid cycle cultivars. Rice straw from more productive cultivars had lower levels of lignin and C fraction as well as higher levels of crude protein and B3 fraction compared with straws from less productive cultivars. However, the main variation in the nutritional value between the samples of rice straw was related to the baling season. The bailing seasons were grouped in two clusters. Straws with better nutritional value were those with lower levels of cell wall fractions, from more productive crops, with early development cycle and baled until March. Rice crop cycle, baling season, and grain production effects explain the variation in the nutritional value of rice straws. Straws with better nutritional value have lower levels of fractions related to secondary cell wall and lignification.

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-The objective of this study was to evaluate the effects of mineral and protein-energy (MPES), exogenous fibrolytic enzyme supplements (ES), combination of MPES + ES, and straw without supplement (WS) on digestibility, fermentation kinetic parameters, cumulative gas production, methane, CO 2 production, and volatile fatty acid concentration of rice straw of low and high nutritional value, estimated by in vitro techniques. The experimental design was randomized and factorial 2 × 4: two straws (low and high nutritional value) incubated with four supplements (MPES, ES, MPES + ES, and WS) and their interactions. Four experimental periods were used, totaling four replications per treatment over time. Data were analyzed by PROC MIXED of SAS. The in vitro dry matter and organic matter digestibilities of the rice straw with high nutritional value was improved by MPES, while the combination of MPES + ES supplements inhibited the digestibility of this straw. Dietary carbohydrate and nitrogen increased through MPES and MPES + ES supplements resulted in an increase in NH 3 -N concentration and a decrease in CO 2 production due to the microbial mass formation. However, this increase was not enough to improve organic matter degradability parameters, cummulative gas production, gas production kinetics, and acetate:propionate ratio and reduce methane emissions. The straw with high nutritional value showed greater content of nitrogen fraction a, effective degradability, cummulative gas production, and methane and CO 2 productions comparing with low-nutritional value straw. The use of MPES and MPES + ES supplements can be used as strategy to mitigate CO 2 in ruminant production systems that use rice straw.Key Words: digestibility, digestion kinetics, fatty acid, gas production, methane Revista Brasileira de Zootecnia

A pesquisa teve por objetivo analisar a produção de leite bovino em diferentes níveis produtivos no município de Pejuçara-RS. Utilizou-se a metodologia de amostragem semiestratificada, não probabilística e de população finita. A pesquisa foi realizada com 35 produtores (90% de intervalo de confiança e 10% de margem de erro). As propriedades foram agrupadas em três estratos de produção: de 0 a 200 litros/dia; de 201 a 500 litros/dia; e acima de 501 litros/dia. A maioria dos produtores de leite possuem idade superior a 50 anos e mais de 20 anos de experiência nessa atividade. Do total apenas 7 produtores possuíam menos de 40 anos de idade. Os sistemas de produção são semi-intensivos, onde os animais são criados em pastagem cultivada e recebem ração e silagem de milho após as ordenhas. Esse sistema, atrelados a boa genética dos animais e o adequado manejo sanitário, promove uma adequada produção de leite animal/ dia. Grande parte da renda do município de Pejuçara é oriunda da atividade leiteira, com isso o trabalho de extensão serve de apoio na tomada de decisão visando melhorias nos pontos críticos e o aprimoramento nos pontos positivos nas diversas propriedades do município.