Avaliação de cultivares de milho colhido em duas alturas de corte para ensilagem

The objective of this study was to evaluate the agronomic characteristics, bromatological-chemical composition and digestibility of 11 corn cultivars (Zea mays) harvested at two cutting heights. Cultivars D 766, D 657, D 1000, P 3021, P 3041, C 805, C 333, AG 5011, FO 01, CO 9621 and BR 205 were evaluated when they were harvested 5 cm above ground (low) and 5 cm below the insertion of the first ear (high). The experiment was designed as random blocks, with three replicates, arranged in an 11 x 2 factorial scheme. Cultivars presented similar productions of forage dry matter and grains. Percentages of stalk, leaf, straw, cob and kernel fractions were different among cultivars, as well as dry matter content of the whole plant at harvest. Considering the whole plant, only the contents of gross energy, nitrogen in neutral detergent fiber, and in vitro neutral and acid detergent fiber digestibility did not differ among cultivars. Increase on the cutting height improved forage quality due to the reduction of stalk and leaf fractions and contents of cell wall constituents.Objetivou-se neste estudo avaliar as características agronômicas, a composição químico-bromatológica e a digestibilidade de 11 cultivares de milho (Zea mays) colhido em duas alturas de corte. As cultivares D 766, D 657, D 1000, P 3021, P 3041, C 805, C 333, AG 5011, FO 01, CO 9621 e BR 205 foram avaliadas quando colhidas 5 cm acima do solo (baixa) e 5 cm abaixo da inserção da primeira espiga (alta). O experimento foi delineado como blocos casualizados, com três repetições, arranjados em esquema fatorial 11 x 2. Os cultivares apresentaram produções semelhantes de matéria seca de forragem e de grãos. As porcentagens das frações colmo, folha, palha, sabugo e grão diferiram entre os cultivares, assim como os teores de matéria seca da planta inteira no momento da colheita. Considerando a planta inteira, apenas os teores de energia bruta, nitrogênio da fração fibra em detergente neutro e a digestibilidade in vitro da fibra em detergente neutro e detergente ácido não diferiram entre os cultivares. O aumento da altura de corte melhorou a qualidade da forragem, devido à redução das frações colmo e folha e dos teores dos constituintes da parede celular

Desempenho produtivo e composição da fração proteica do leite de vacas leiteiras sob suplementação com fontes de gordura

The objective of this study was to evaluate the use of fat sources in rations for lactating cows on the productive performance and composition of milk protein fraction. Twelve Holstein cows were used, grouped in three balanced 4 × 4 Latin squares, fed with the following rations: control; refined soybean oil; whole raw soybean; and calcium salts of unsaturated fatty acid (Megalac-E). Dry matter and nutrient intake, and daily milk production were evaluated. The samples used to analyze milk composition were collected in two alternate days and were obtained from two daily milking. Milk composition and total nitrogen, non-protein nitrogen and non-casein nitrogen ratios were analyzed. The casein, serum protein and true protein ratios were obtained by difference. Dry matter and nutrient intakes were lower when cows received the diet containing calcium salts of fatty acids, in relation to the control diet. Among the diets with fat sources, the one with whole raw soybean and calcium salts decreased milk production. There was no effect of fat sources added to the diet on crude protein, non-protein nitrogen, non-casein nitrogen, true protein, casein, casein/milk true protein ratio and serum protein. Similarly, the experimental diets did not influence the protein fractions when expressed in percentage of milk crude protein. The utilization of fat sources in diets changes milk production and composition of lactating cows, but does not influence the composition of milk protein fractions.Objetivou-se com este estudo avaliar a utilização de fontes de gordura em rações para vacas em lactação sobre o desempenho produtivo e a composição da fração proteica do leite. Foram utilizadas 12 vacas da raça Holandesa, agrupadas em três quadrados latinos balanceados 4 × 4, alimentadas com as seguintes rações: controle; óleo de soja refinado; grão de soja in natura; e sais de cálcio de ácidos graxos insaturados (Megalac-E). Avaliaram-se o consumo de matéria seca e de nutrientes, e a produção diária de leite. As amostras utilizadas para análise da composição do leite foram coletadas em dois dias alternados e foram provenientes das duas ordenhas diárias. Foram analisados a composição do leite e os teores de nitrogênio total, nitrogênio não-proteico e nitrogênio não-caseinoso. Por diferença, foram obtidos os teores de caseína, proteína do soro e proteína verdadeira. O consumo de matéria seca e de nutrientes foi menor quando as vacas receberam a ração contendo sais de cálcio de ácidos graxos em relação à ração controle. Entre as rações com fontes de gordura, aquela com grão de soja e sais de cálcio diminuiu a produção de leite. Não houve efeito das fontes de gordura adicionadas nas rações sobre os teores de proteína bruta, nitrogênio não-proteico, nitrogênio não-caseinoso, proteína verdadeira, caseína, relação caseína/proteína verdadeira no leite e proteína do soro. De forma semelhante, as rações experimentais não influenciaram as frações proteicas expressas em porcentagem da proteína bruta do leite. A utilização de fontes de gordura nas rações altera a produção e a composição do leite de vacas em lactação, mas não influencia a composição das frações proteicas do leite

Effect of unsaturated fatty acid supplementation on digestion, metabolism and nutrient balance in dairy cows during the transition period and early lactation

The objective of this study was to evaluate the influence of unsaturated fatty acids in diets for dairy cows during the transition period and early lactation on intake, digestion and nutrient balance. Thirty-six multiparous and pregnant Holstein cows were randomly distributed to receive one of the experimental diets in the period from 35 days before the expected date of parturition to 84 days post-partum. Diets were fed as a total mixed ration and were as follows: control (C); soybean oil (SO), based on inclusion of 30 g/kg (DM basis); and calcium salts of unsaturated fatty acids (CS), based on inclusion of 30 g/kg (DM basis). Pre-partum dry matter intakes (DMI) of cows fed C, SO and CS were 11.9, 9.5 and 9.6 kg/d, respectively. Postpartum DMI was affected by experimental diets (18.5, 15.0 and 17.4 kg/d for C, SO and CS, respectively). The energy balance in the transition period of animals fed CS was 4.41 Mcal/d higher than cows fed SO and 1.3 Mcal/d higher than cows fed C. Supplementing cows with unsaturated fatty acid sources is a strategy for dairy cows in the transition perio

Características bromatológicas e digestibilidade in vitro de quatro variedades de cana-de-açúcar submetidas ou não à aplicação de cal virgem

The experiment was conducted to evaluate the bromatological characteristics and the in vitro digestibility of four sugarcane varieties, subjected or not to hydrolysis, with quicklime. A completely randomized design was employed with three replications arranged in a 4 × 2 factorial scheme, with four sugarcane varieties (SP 52454, RB 867515, RB 855536 and IAC 862480), hydrolyzed or not. There was significant effect on brix (p < 0.05) and industrial fiber (p < 0.05), and IAC 862480 variety had the lowest levels of industrial fiber. There were no significant difference (p &gt; 0.05) in neutral detergent fiber, acid detergent fiber and lignin levels among the sugarcane varieties under analysis and for the sugarcanes, hydrolyzed or not. The use of sugarcane hydrolysis with 1% quicklime improves the in vitro digestibility of NDF and ADF, regardless of the variety studied. Hydrolysis with 1% quicklime did not alter the sugarcane chemical composition

Fatty acid composition of the longissimus dorsi muscle in crossbred steers fed different sources of fatty acids

The objective of this study was to evaluate the fatty acid composition of the longissimus dorsi muscle in carcasses of 3/4 Bos taurus taurus 1/4 Bos taurus indicus steers fed different sources of fatty acids. Thirty-six steers aged 14 months, with a mean live weight of 320 kg, were fed the following diets for 96 days:1) control diet, containing no supplemental fat source; 2) CaSFA, diet containing 50 g calcium salts of fatty acids per kg total dry matter; 3) CS diet, containing 210 g cottonseed per kg total dry matter. The fatty acid composition of the longissimus dorsi muscle was determined by gas chromatography. No difference in slaughter weight, carcass weight, backfat thickness, or longissimus dorsi muscle area was observed between animals receiving the diets CaSFA and CS. Animals consuming the two fat-supplemented diets presented higher concentrations of oleic (C18:1), palmitic (C16:0) and stearic (C18:0) acids, corresponding to an average 80.76% of total fatty acids, and higher concentrations of vaccenic acid (C18:1 t11) in the muscle when compared with the control group. Supplementation of the diet of feedlot crossbred steers with CaSFA or cottonseed did not promote significant alterations in the lipid composition of the longissimus dorsi muscle

Digestion of feed fractions and intake of heifers fed hydrolyzed sugarcane stored for different periods

The objective of this study was to evaluate, in Nellore heifers, intake and digestibility of hydrolyzed sugarcane stored for different periods. The experimental design used was a 4 × 4 Latin square, four diets, four Nellore heifers with ruminal cannulas (initial body weight 285.4±23.08 kg and average initial age 14 months) and four periods of 21 days. The diets were composed by fresh sugarcane (time zero) or hydrolyzed sugarcane with addition of 0.5% of hydrated lime, stored for 24, 48 or 72 hours, as the unique forage. Intake and digestibility of feed fractions, nitrogen balance, microbial synthesis efficiency, total number of ruminal protozoans and ammoniacal nitrogen did not significantly change by storing sugarcane with addition of 0.5% of hydrated lime. Sugarcane pH varied quadratically for storage time, with maximum pH of 7.02 after 24 hours from lime addition. Ruminal liquid pH values were higher for heifers fed fresh sugarcane, in comparison with those fed hydrolyzed sugarcane. Sugarcane treated with 0.5% of hydrated lime stored for up to 72 hours does not change ruminal digestion to alter the amount of feed consumed by pubescent Nellore heifers. Thus, lime is a viable technology, once it allows long-duration storage and bee control on treated forage, which contributes to animal feeding logistics

Utilização de quitosana na alimentação de ruminantes

O objetivo desta revisão foi avaliar os possíveis efeitos da utilização\ud da quitosana na nutrição de ruminantes e demonstrar os resultados obtidos\ud com sua aplicação na dieta de bovinos no Brasil. Foram utilizados neste\ud estudo 8 novilhos canulados da raça Nelore. Os animais foram submetidos\ud à 4 diferentes tratamentos, sendo além do controle, fomecidas as doses de\ud 50 mg, 100 mg ou 150 mg/kg de peso vivo (PV) de quitosana diariamente\ud e inseri da no rúmen. Na adição da concentração de 150 mg/kg de PV de\ud quitosana observou-se diminuição sobre o consumo de fibra detergente neutro\ud (FDN), expressos em kg/dia e em porcentagem de PV do animal. A inclusão\ud de quitosana na dieta proporcionou aumento da digestibilidade da matéria seca\ud (MS), matéria orgânica (MO), proteína bruta (PB),carboidratos totais (CT),\ud FDN e nutrientes digestíveis totais (NDT). Houve efeito quadrático sobre\ud o N-NH3 com a inclusão de quitosana na dieta. A inclusão de quitosana na\ud dieta alterou as proporções molares de AGCC individualmente. O aditivo\ud proporcionou aumento das concentrações de propionato (mmol/L) a medida\ud que se elevou as concentrações de quitosana e de forma semelhante houve\ud aumento de 7,47% para as porcentagens molares de propionato. Houve\ud diminuição da relação acetato:propionato, principalmente com a inclusão de\ud 150mg/Kg de peso vivo de quitosana diariamente.Foi observado também neste\ud trabalho, efeito linear decrescente para a proporção molar de butirato.Assim\ud como esperado as concentrações de glicose plasmática foram influenciadas\ud notadamente neste estudo, resultando num incremento de 18,58%, 26,35%,\ud 23,68% respectivamente para o controle versus as três concentrações\ud utilizadas. Estes dados são coesivos com o aumento também linear obtido\ud na participação do propionato no total de AGCC. Embora estejam dentro dos...Os organizadores autorizam a reprodução total ou parcial deste trabalho, para qualquer meio convencional ou eletrônico, para fins de estudo e pesquisa, desde que citada a fonte