COMPORTAMENTO DA INGESTÃO EM BOVINOS (RUMINANTES) EM PASTAGEM DE CAPIM Brachiaria decumbens NA REGIÃO CENTRO-OESTE DO BRASIL

An experiment has been carried out aiming to evaluate the ingestion behavior of young heifers, heifers and cows in pastures of Brachiaria decumbens, in the system of continuous stocking with three categories representing the treatments, each one with ten repetitions. The experimental period  was of 30 days, being 20 for adaptation of the experimental animals and 10 for three evaluations with duration of 24 hours each, in intervals of five days. The results of the Tukey test demonstrated that the cows grazed during more time (12 hours) than the young heifers (0.5 hours) and the heifers (10.25 hours). Statistic differences were not observed among the animals for the rumination time (7.25, 7.39 and 7.40, respectivety). The cows displayed larger bite rate (41.30) than the heifers and the young heifers. This result suggest that there was a compensatory mechanism between the times of grazing and the bite rates, so that the animals with more nutritional requirement regulated the amount of ingested forage, incrementing the grazing time.Foi conduzido um experimento com o objetivo de avaliar o comportamento na ingestão de bezerras, novilhas e vacas leiteiras em pastagens de Brachiaria decumbens, no sistema de lotação contínua com taxa de lotação variável. O delineamento experimental foi inteiramente casualizado, com três categorias animais representando os tratamentos, cada um com dez repetições. O período experimental foi de 30 dias, sendo 20 para adaptação dos animais e 10 para avaliações, que consistiram de três, com duração de 24 horas cada, em intervalos de cinco dias. O teste de Tukey demonstrou que as vacas pastejaram mais tempo (12 horas) que as novilhas (10,50 horas) e as bezerras (10,25 horas). Não foi observada diferença estatística entre os animais para o tempo de ruminação (7,25, 7,39 e 7,40, horas respectivamente). A taxa de bocados diurnos foi maior para as vacas do que para os novilhos e bezerros. Os resultados sugerem que houve um mecanismo de compensação entre os tempos de pastejo e as taxas de bocado, de modo que os animais mais exigentes pudessem regular a quantidade de forragem ingerida aumentando o tempo de pastejo

Effect of salt concentrations on in vitro rumen fermentation of cellulose, starch, and protein

The aim of this study was to evaluate the effects of various concentrations of three salts (sodium chloride (NaCl), magnesium chloride (MgCl2), and calcium chloride (CaCl2)) on the in vitro rumen fermentation of cellulose, starch, and protein substrates. Six salt concentrations were tested, separately, namely 0, 100, 200, 400, 800, and 1600 mg/dL. The experiment was conducted using the completely randomized design in a 6 × 3 × 3 factorial arrangement with main effects of salt concentration and salt type (six levels of three salts (NaCl, MgCl2, or CaCl2) (0, 100, 200, 400, 800, and 1600 mg/dL) into three substrates [starch, cellulose, and glucose]) with three replicates. Cellulose- and glucose-fermenting bacteria were sensitive to NaCl concentrations greater than 400 mg/dL (17.48 decisiemens per metre (dS/m)) and 800 mg/dL (20.55 dS/m) in the media, respectively. In contrast, starch-fermenting bacteria continued to grow in NaCl concentrations up to 1600 mg/dL (29.09 dS/m). Thus, it was concluded that starch-fermenting microorganisms tolerated higher concentrations of NaCl compared with the other microbial groups. Cellulose-fermenting microorganisms are less tolerant to MgCl2 in relation to the other microbial groups. Starch, cellulose-, and glucose-fermenting bacteria from cattle tolerate CaCl2 concentrations of up to 1600 mg/dL (12.26 dS/m). These results suggest that brackish water may be used for ruminants. However, it is important perform an analysis of that water and then to adjust diets to minimize the effects of types of salt and concentrations of salt on rumen microorganisms. Keywords: brackish water, dissolved salts, rumen microbes, water qualit

Fermentation characteristics and chemical composition of elephant grass silage with ground maize and fermented juice of epiphytic lactic acid bacteria

This study aimed to evaluate the microbial populations, fermentation profile, dry matter recovery and chemical composition of elephant grass silage with ground maize (GM) and the fermented juice of epiphytic lactic acid bacteria (FJLB). A factorial design was used with four levels of GM (0 g/kg, 50 g/kg, 100 g/kg and 200 g/kg), untreated or treated with FJLB, in a completely randomized design with five replicates. A pre-experiment was undertaken to determine the optimum level of sucrose to be added to fermented juice for the development of epiphytic microflora. In this pre-experiment, a completely randomized design with three replications was used. The treatments were represented by the levels of sucrose (0 g/kg, 5 g/kg, 10 g/kg, 20 g/kg, 40 g/kg, 60 g/kg and 80 g/kg, fresh matter basis). The microbial populations, dry matter recovery, and effluent losses were affected by the interaction between GM and FJLB. Dry matter (DM) and crude protein (CP) contents increased linearly with the inclusion of GM. The addition of GM enhanced the fermentation process via a reduction in losses, and improvements were identified in the nutritional value of elephant grass silages. The use of fermented juice increased dry matter recovery, and its effect was more pronounced when ground maize was added.Keywords: dry matter recovery, lactic acid, microbiology, Pennisetum purpureu

DEGRADABILIDADE in vitro DA PROTEÍNA DE ESPÉCIES ARBÓREAS DO SEMI-ÁRIDO BRASILEIRO

This experiment was carried out to evaluate the protein degradability in vitro of arboreal plants from Brazilian semi-arid. The plants tested were angico (Anadenanthera colubrina), algaroba (Prosopis juliflora), espinheiro (Acacia glomerosa), juazeiro (Ziziphus joazeiro) and soybean meal, which had crude protein values of 22,5 16,0, 22,0, 19,0 and 38,0%, respectively. Samples (60 mg) were incubated with McDougal (8 ml) and inoculated ruminal fluid (2 ml). Aliquots (1 ml) were taking after 0, 6, 12, 24, 36 and 48 hours for analysis of ammonia, soluble protein and microbial protein. Soybean meal and the algaroba showed larger ammonia production and concentration of soluble protein compared to the other treatments. Soybean meal also displayed higher values for microbial protein. The treatment with angico was the one that displayed closed values towards soybean in regard to microbial protein, in spite of showing lesser ammonia production. The largest value of potential degradability 66,47%, was observed for the treatment with soybean meal, followed by the algaroba 46,27% and of the angico 45,20. Very low degradability was observed for the espinheiro and juazeiro, 19,16 e16,63%, respectively. Among the studied plants the angico and the algaroba were better sources of protein.O experimento teve como objetivo avaliar a degradabilidade in vitro da proteína de plantas arbóreas do semi-árido brasileiro e do farelo de soja. As plantas utilizadas foram angico (Anadenanthera colubrina), algaroba (Prosopis juliflora), espinheiro (Acacia glomerosa), juazeiro (Ziziphus joazeiro) e o farelo de soja, com valores de proteína bruta de 22,5 16,0, 22,0, 19,0 e 38,0%, respectivamente. Amostras de cada planta (60 mg) foram incubadas em 8 ml de meio tampão de McDougal, com adição de 2 ml de inóculo ruminal. Nos tempos 0, 6, 12, 24, 36 e 48 horas após a incubação foi retirada uma alíquota de 1,0 ml para análise de amônia, proteína solúvel e proteína microbiana. O farelo de soja e a algaroba proporcionaram maiores produção de amônia e concentração de proteína solúvel em relação aos outros alimentos, sendo que o farelo de soja apresentou maior valor de proteína microbiana. O tratamento com o angico foi o que mais se aproximou à soja com relação ao valor de proteína microbiana, apesar da sua menor produção de amônia. O maior valor de degradabilidade potencial 66,47 %, foi observado no tratamento com farelo de soja, seguidos dos tratamentos da algaroba 46,27% e angico 45,20%. Foram observados valores de degradabilidade muito baixos para o espinheiro e juazeiro, 19,16 e 16,63%, respectivamente. O angico e a algaroba apresentaram-se como melhores fontes de proteína entre as plantas avaliadas