 RESUMOAvaliaram-se o fracionamento de carboidratos e a degradabilidade in situ da matéria seca (MS) e da fibra em detergente neutro (FDN) da cana-de-açúcar tratada com óxido de cálcio (CaO). Foram testadas as porcentagens de 0; 0,75; 1,5; 2,25; 3,0; 3,75 e 4,5% de CaO, e o material testemunha (cana-de-açúcar in natura) para a avaliação do fracionamento de carboidratos, e as porcentagens de 0; 1,5; 3,0 e 4,5% de CaO para a avaliação da degradabilidade in situ da MS e da FDN. O CaO foi adicionado em pó na canade-açúcar, em porcentagem da matéria natural, por 24 horas. A porcentagem de inclusão de CaO na canade-açúcar proporcionou valores mais baixos para teores de carboidratos totais (CT) comparados aos valores da cana-de-açúcar in natura. Observou-se crescimento linear das frações A+B1 e B2, e redução na fração C da cana-de-açúcar em função da porcentagem de CaO. Os maiores valores de fração insolúvel potencialmente degradável da MS e menores de fração indigestível (Ip) da FDN foram observados na cana-de-açúcar com 3,0 e 4,5% de CaO. A adição de 3,0 e 4,5% de CaO na cana-de-açúcar promove diminuição da fração indigestível dos carboidratos e melhores taxas de degradação ruminal tanto da MS quanto da FDN. Levels 0, 0.75, 1.5, 2.25, 3.0, 3.75 and 4.5% CaO, and Palavras-chave: cal, Saccharum officinarum, tratamento químico ABSTRACT Were evaluated the fractioning of carbohydrates and in situ dry matter (DM) and neutral detergent fiber (NDF) of sugarcane treated with calcium oxide (CaO).

In vitro rumen fermentation kinetics of diets containing oldman saltbush hay and forage cactus, using a cattle inoculum [ ABSTRACTThe aim of this experiment was to evaluate, by means of the semi-automated in vitro gas production technique, fermentation kinetics of carbohydrates and degradability of dry matter (DM) and organic matter (OM) of diets containing oldman saltbush hay levels (8.4; 18.8; 31.2 and 48.3%) associated to forage cactus in natura. Pressure readings of the gases were done with a pressure transducer at 2, 4, 6, 8, 10, 12, 17, 20, 24, 28, 34, 48, 72 and 96h post-inoculation. The rumen kinetics was described by the following parameters: maximum potential of gas production, lag time and production rates of gas (k), fibrous carbohydrates (FC) and nonfibrous carbohydrates (NFC). It could be observed that the addition of oldman saltbush hay to the diets promoted a quadratic effect in the production of gases originated from NFC. However, there was no significant effect on the production of gases originated from FC and on production rates of gases from NFC and FC. The degradability of DM and OM did not differ due to the addition of oldman saltbush hay. The use of 8.4% hay and 74.9% forage cactus promoted the maximum potential of production of gases from the fibrous fraction of diets containing cactus and oldman saltbush hay.

The aim of this study was to identify the most adequate level of calcium oxide (CaO) in the treatment of sugar cane by evaluating the chemical composition and in vitro digestibility of dry matter. The sugar cane was homogenized with CaO levels 0, 0.75, 1.5, 2.25, 3.0, 3.75 and 4.5%, in natura matter, for 24 hours. The dry matter and mineral matter increased, while the organic matter of the sugar cane decreased (P <0.05) linearly as a result of the CaO levels. The CaO had no effect on the levels of crude protein and ether extract. The phosphorus concentration remained unchanged, but there was a significant increase (P<0.05) in the calcium content. The contents of neutral detergent fiber, acid detergent fiber and cellulose decreased linearly with the levels of CaO. The average levels of indigestible dry matter and indigestible neutral detergent fiber significantly decreased with increasing levels of CaO. The results showed that the in vitro dry matter digestibility (IVDMD) was different between fresh sugar cane and sugar cane with added levels of CaO from 1.5%. The IVDMD and nutritional value of the sugar cane was improved by adding 1.5% CaO based on fresh content.Keywords: additive, forage, hydrolysis, Saccharum, alkaline treatment CaO 0; 0,75; 1,5; 2,25; 3,0; 3,75 RESUMO O objetivo foi identificar o nível mais adequado de óxido de cálcio (CaO) no tratamento da cana-deaçúcar por meio da avaliação da composição química e a digestibilidade in vitro da matéria seca. A cana-de-açúcar foi homogeneizada adicionando os níveis de

The objective of this study was to evaluate, based on chemical composition and in vitro dry matter (DM) digestibility, silages of different sugarcane genotypes after exposure to different doses of calcium oxide (CaO) and to identify that most appropriate dose for use in ruminant feed. The experiment was conducted using a completely randomized 3 9 4 factorial arrangement with three sugarcane genotypes ('IAC-862480', 'SP-791011' and 'CTC-3') and four levels of the additive CaO (0, 15, 30 and 45 g kg À1 ). A quadratic effect was observed (P < 0.05) for DM content in the silages of genotypes 'SP-791011' and 'CTC-3'. The organic matter content of genotypes 'SP-791011' and 'CTC-3' showed a negative linear effect that was associated with the addition of CaO, which promoted an increase in the mineral matter (MM) content in the silages. There was no effect (P > 0.05) of genotype or an interaction effect between genotype and CaO level on crude protein content in the silages. There was an interaction effect (P < 0.05) between genotype and CaO level on the level of neutral detergent fiber in the studied silages and the development of this interaction revealed a linear decrease in neutral detergent fiber in genotype IAC-86280 and a quadratic effect (P < 0.05) for genotypes 'SP-791011' and 'CTC-3'. Potentially degradable DM (pdDM) values showed a positive quadratic function with maxima at 34.8 g kg À1 CaO. The results obtained for potentially degradable neutral detergent fiber (pdNDF) showed that there was a negative linear effect for genotype 'SP-791011' and a quadratic effect with the maximum critical point for genotypes 'IAC-862480' and 'CTC-3'. Total DM losses decreased with levels of CaO. All genotypes evaluated showed potential for silage production. The addition of CaO in the ensiling of sugarcane at up to 45 g kg À1 reduces gas and effluent losses and increases the DM recovery of the silages.