Objetivou-se avaliar o efeito da adição de Saccharomyces cerevisiae nos níveis 0; 0,2; 0,4 e 0,6 g/L, sobre a digestibilidade in vitro da matéria seca (DIVMS), proteína bruta (DIVPB) e fibra em detergente neutro (DIVFDN) em dietas contendo, na MS, 100, 75, 50 e 25% de capim coast-cross. O delineamento foi inteiramente casualizado, com esquema fatorial 4x4. O líquido ruminal foi coletado de um bovino canulado e os alimentos foram incubados por meio da técnica dos dois estágios (48 horas + 24 horas), utilizando-se o rúmen artificial. Os dados foram interpretados por análise de variância e estudos de regressão. A elevação da levedura proporcionou aumentos nas DIVMS, DIVPB e DIVFDN em todos os tratamentos, com exceção do nível de 0,6 g/L nas dietas contendo 100, 75 e 50% de volumoso para DIVMS e DIVFDN, e 100 e 75% para DIVPB, as quais apresentaram comportamento quadrático. Concluiu-se que, nas dietas com proporção de volumoso igual ou superior a 50%, a digestibilidade pode ser melhorada com a utilização de levedura até o nível de 0,4 g/L. Nas dietas com mais de 50% de concentrado, a melhora na digestibilidade ocorre linearmente com a elevação do nível de levedura.

The objective of this work was to evaluate the effect of Saccharomyces cerevisiae at levels 0; 0.2; 0.4 and 0.6 g/L on the in vitro digestibility of dry matter (IVDDM), crude protein (IVDCP) and neutral detergent fiber (IVDNDF) in diets containing, in DM, 100, 75, 50 and 25% Cynodon dactylon grass. The experimental design was completely randomized with 4x4 factorial scheme. The rumen fluid was collected from a cannulated cattle and food were incubated by two stages technique (48 hours + 24 hours), in artificial rumen. The data were interpreted by analysis of variance and regression studies. The elevation of the yeast has provided increases in IVDDM, IVDCP and IVDNDF in all treatments, except at the level of 0.6 g/L in the diets containing 100, 75 and 50% roughage for IVDDM and IVDNDF, and 100 and 75% for IVDCP, which presented quadratic behavior. We concluded that in diets with proportion of roughage equal or above 50%, the digestibility can be improved with the use of yeast to the level of 0.4 g/L. In diets with more than 50% of concentrate the improvement in digestibility occurs linearly with increasing levels of yeast.

The objective of this study was to evaluate the milk production, composition, milk fatty acid profile, butter texture and blood parameters of Holstein cows fed corn silage and concentrate containing one of the following: ground sunflower seeds; ground sunflower seeds treated with 50 g of lignosulfonate/kg of sunflower dry matter; pelleted sunflower seeds; or ground sunflower seeds pelleted and treated with 50 g of lignosulfonate/kg of sunflower dry matter. Four lactating cows were used, each with 130±28 days in lactation and a body weight of 569±63 kg. These animals were distributed in a Latin square design with four periods of 21 days each, with 14 days of adaptation and seven days of data collection. The diets were formulated to meet nutritional requirements and had a forage:concentrate ratio of 60:40. The milk fat was lower in the pelleted treatments. The concentrations of 16:1 n-11 and trans18:1 n-9 in the milk increased, and the n-6:n-3 ratio was higher for the pelleted treatments. The firmness and adhesiveness of the butter and the blood parameters analyzed were not affected by the treatments. Addition of lignosulfonate is not effective in protecting polyunsaturated fatty acids from the ruminal biohydrogenation process, and the pelleting process has little effect on the milk fatty acid profile and can not change the butter texture.

The objective of this study was to evaluate intake, in vitro and apparent digestibility and ruminal parameters of Holstein cows that were confined and fed corn silage and concentrate containing: ground sunflower seeds (GS); ground sunflower seeds treated with 5% lignosulfonate (GSL); pelleted sunflower seeds (PS); or ground and pelleted sunflower seeds treated with lignosulfonate (PSL). Four lactating cows with 130±28 days of lactation and body weights of 569±63 kg were used. These animals were distributed in a Latin square design with four diets and four periods of 21 days each. There were no differences in the intakes (% body weight) of dry matter (DM), organic matter (OM), mineral matter (MM), crude protein (CP), neutral detergent fiber (NDF) or acid detergent fiber (ADF). The apparent digestibility of DM, OM, CP, EE, NDF, ADF and NFC were similar for all the diets, with a tendency towards decreased CP digestibility for all the pelleted diets (65.79%) compared with the non-pelleted diets (69.66%). A negative effect of lignosulfonate was observed for the in vitro digestibility (IVD) of DM, and a negative tendency was observed for the IVD of OM. Pelleting decreased the concentration of acetic acid (55.95 × 58.82 mM) in rumen fluid. There was no effect of diet on pH (6.17) or ammonia nitrogen concentration (18.19 mg/dL). Pelleting and lignosulfonate do not promote the protective effect of sunflower seed nutrients as expected, and it may be more feasible to provide ground sunflower seed.