Advances in knowledge of ruminant nutrition and metabolism during the second half of the twentieth century have been reviewed. Part I is concerned with metabolism in the rumen: Part II discusses utilization of nutrients absorbed from the rumen and lower tract to support growth and reproduction. The time frame was prompted by the crucial advances in ruminant physiology which arose from the work ...

In recent years there has been an increased interest in bacteriocins, primarily among the lactic acid bacteria, as a result of their applications in food preservation. There has been very little research on the occurrence of bacteriocin production among anaerobic bacteria. Recently, we reported a high incidence of bacteriocin-like inhibitory activity in isolates of the rumen anaerobe Butyrivibr...

Materials and Methods Dietary supplementation of probiotic yeast ( ) was noted to improve the animal performance by improving the digestibility of nutrients and rumen bacterial number [1]. Addition of yeast culture, as a probiotic, in animal feeds improves fibre digestion [2], the cellulolytic activity of rumen microbes [3], and reduces the lactate accumulation and oxygen concentration in rumen...

Energy-rich diets can challenge metabolic and protective functions of the rumen epithelial cells, but the underlying factors are unclear. This study sought to evaluate proteomic changes of the rumen epithelium in goats fed a low, medium, or high energy diet. Expression of protein changes were compared by two-dimensional differential gel electrophoresis followed by protein identification with ma...

Four crossbred wethers equipped with runten fistulas were used to study changes in rumen pH, motility and the synthesis of volatile fatty acids and lactic acid during the onset and recovery of induced lactic acidosis. Acidosis was induced by the addition of sucrose (15 g/kg BW) in 700 ml of water through the fistula. Mean maximum lactic acid concentration was near or in excess of 100 mM of rume...

Volume and type of medium, carbohydrate concentration, carbohydrate ratios, and inoculum level were investigated as possible factors influencing total colony counts of anaerobic rumen bacteria obtained in roll tubes (18 by 150 mm). Colony counts were lower when the rumen fluid was clarified by centrifugation before inclusion in the medium; however, decreasing the volume of 40% rumen fluid gluco...

Enumeration by means of light microscopy showed that from 0.4 x 10(8) to 2.0 x 10(8) spirochetes were present per ml of bovine rumen fluid. Viable cell counts yielded slightly lower values, ranging from 0.1 x 10(8) to 1.2 x 10(8) spirochetes per ml of rumen fluid. The antibiotic rifampin, which served as a selective agent for rumen spirochetes, was added to agar media used in the estimation of ...

The purpose of this study was to determine the effect of rumen inoculum from heifers with fast vs. slow rate of in situ fiber digestion on the fermentation of complex versus easily digested fiber sources in the forms of untreated and Ammonia Fiber Expansion (AFEX) treated barley straw, respectively, using an artificial rumen simulation technique (Rusitec). In situ fiber digestion was measured i...

Intake and excretory patterns, N and mineral balance, rumen fluid characteristics and acid-base status were measured for 15 days in five nonfistulated and six rumen-fistulated wethers. The animals were placed in metabolism crates and fed alfalfa hay from day 1 through 5, a 65% concentrate diet from day 6 through 10 and an 85% concentration diet from days 11 through 15. All diets were pelleted a...

The osmotic pressure of solutions in the ventral sac of the rumen of the conscious cow was varied with Na Cl or mannitol. The mucosal blood flow measured by HTO clearance was minimal when the lumen contained an isotonic solution and rose threefold when the rumen was hypo- or hypertonic to plasma by 150 mosmol/kg. Thus osmotic gradients actoss the rumen epithelium stimulated mucosal blood flow. ...