An experiment was conducted, on extraction and analysis of n-alkanes, to investigate the use of n-alkane (C35) present in forages as an internal marker for the digestibility determination. Samples of forages and feces were taken from conventional digestibility trials, which were previous conducted from 1978 to 1982. The C35 underestimated the dry matter and organic matter digestibilities, presenting an average difference in relation to in vivo of 4.68 (± 0.69) and 4,43 (± 0.85) perceptual units, respectively. The coefficient of […]

The effects of dietary concentrate levels were evaluated on the microbial synthesis efficiency, the nitrogenous compounds balance, the ammonia concentrations and the ruminal fluid pH, the ruminal digesta passage rate and the endogenous losses of nitrogen compounds (N). Five F1 Simental x Nellore bulls fistulated in the rumen, abomasum and ileum, full fed diets with 25.0; 37.5; 50.0; 62.5; and 75.0% of concentrate and allotted to 5×5 Latin square, were used. The ammonia concentrations and the ruminal pH were determined […]

Fifty-one postpartum Nellore cows were used to study the effect of the utilization of protein concentrate, during the summer time, on the forage intake, weight gain and body condition score changes after parturition of Nellore cows. The animals were randomly allotted in the following treatments: T0 – without supplementation; T1 – supplemented with 1 kg and T2 – supplemented with 2 kg of concentrate with 40.8% of crude protein, during 105 days. During this period, body score and body weight […]

The digestibilities of dry matter (DM), crude protein (CP), ether extract (EE), neutral detergent fiber (NDF), gross energy (GE) and total digestible nutrients (TDN) were determined by using four internal markers (acid detergent fiber – ADF and lignin and acid insoluble ash – AIA). The three first markers were submitted to in vitro disappearance for three and six days and the results were compared with data determined by total feces collection. The nutrient digestibility estimated by NDF, ADF and lignin […]

Forty-eight crossbreed beef cattle were used to evaluate four commercial mineral supplements: Treatment A- Salt + protein without urea (20% crude protein); B – salt + protein with urea (52,5 % crude protein), C) mineralized salt; D) mineralized salt with urea (91% crude protein). The animals were distributed into 24 plots of Braquiaria decubens grass, with supplementation of (10.5 kg/an/day) of sugar cane, during 112 days, with 28 days of adaptation and 84 days of data collection. The animals were […]

Thirty two Santa Gertrudis young bulls with an initial weight of 230 kg and 9 months of age were used in a comparative slaughter experiment with a 2 x 2 factorial arrangement with two concentrate levels, 80 and 20%, and two energetic ingredients in the concentrate, corn grain or pelletized citrus pulp. Four animals were slaughtered after the adaptation period for the determination of the initial body composition of lot and those that received diets with 80 and 20% of […]

The experiment was conducted to evaluate the ruminal pH and ammonia concentration (N-NH3) in rumen liquor collected at 3, 6 and 12 hours after feeding using four ruminal fistulated European x Zebu steers. The forage leaves: stems ratio and neutral detergent fiber (NDF) and acid detergent fiber in situ ruminal degradability of the leaflets from three tropical legumes (leucaena, Leucaena leucocephala; pigeon pea, Cajanus cajan; and glycine, Neonotonia wightii) and leaves from two others tropical forages (ramie, Boehmeria nivea and […]

This work, evaluated by means of an economically simulation, the beef production systems with heifers calving by first time at two (“one year” system), three (“two years” system) and four (“traditional” system) years old. In “one year” system, the female calves had three different nutritional systems during 100 days, after weaning in the first autumn/winter, constituted by one of the alternatives: a) continuous grazing on cultivated annual ryegrass – PAST; b) continuous grazing on natural pasture plus diet – CNR; […]

Fifteen Nellore steers were allotted to three treatments, consisting of a basal diet, which will be able to provide gains of about 600 g/day, supplemented (15 or 11 g P/day) or not (5 g P/day) with monoammonium phosphate in order to evaluate the alterations in bone, plasma and fecal measurements due to P deficiency. Rib biopsies were taken at 60 and 250 days of trial, plasma samples were taken every 15 days, and fecal grab samples were analyzed in seven […]

The objective of the present study was to determinate the nitrogenous compounds fractions present in the extrusa of grazing cattle maintained in a natural grassland in the Zona da Mata region, MG. The samples were obtained by using four esophageal fistulated steers in two experimental periods during the rainy season of 1996, and three of these animals were used to take samples in two experimental periods during the dry season of the same year. In order to obtain the nitrogen […]