The purpose of this study was to assess the in vitro antimicrobial activity of alkaloid-enriched extracts from Prosopis juliflora (Fabaceae) pods in order to evaluate them as feed additives for ruminants. As only the basic chloroformic extract (BCE), whose main constituents were juliprosopine (juliflorine), prosoflorine and juliprosine, showed Gram-positive antibacterial activity against Microc...

OBJECTIVE Manipulating the fermentation to improve the performance of the ruminant has attracted the attention of both farmers and animal scientists. Propionate salt supplementation in the diet could disturb the concentration of propionate and total volatile fatty acids in the rumen. This study was conducted to evaluate the effect of calcium propionate supplementation on the ruminal bacterial c...

Effects of a bacterial probiotic (BP) on ruminal fermentation and plasma metabolites were evaluated in four Holstein cattle (body weight, 645 ± 62 kg; mean ± SD) with induced subacute ruminal acidosis (SARA). SARA was induced by feeding a SARA-inducing diet, and thereafter, 20, 50 or 100 g per head of a commercial BP was administered for 7 consecutive days during the morning feeding. Cattle wit...

A ruminal fermentation study was used to investigate the relationship between forage quality and monensin-dependent amino acid-sparing. Two fistulated cows were fed three concentrations of chopped (2.5 to 5.0 cm in length) timothy and alfalfa hays (100:0, 50:50 and 0:100) and two levels of monensin (0 and 350 mg.cow-1.d-1). The diets were offered 12 times per day (9 kg of DM/d), and the rumen r...

The digestion kinetics of a variety of pure celluloses were examined by using an in vitro assay employing mixed ruminal microflora and a modified detergent extraction procedure to recover residual cellulose. Digestion of all of the celluloses was described by a discontinuous first-order rate equation to yield digestion rate constants and discrete lag times. These kinetic parameters were compare...

Two groups of Merino sheep (with or without rumen fistulae) were used to study the effect of feeding maize-silage (compared to hay) on: thiamine concentrations in rumen fluid, tissues and organ; blood transketolase activity; microbial fermentation in the rumen. After sheep were transferred from a hay diet to maize-silage, thiamine concentrations in ruminal fluid fell to about 25% of control val...

Eight multiparous, ruminally cannulated Holstein cows averaging 40 d in milk and 575 kg BW at the start of trial were in a replicated 4 x 4 Latin square arrangement (28-d periods) to determine the effects of dietary nonfiber carbohydrate (NFC) level and Aspergillus oryzae fermentation extract (AO) on intake, milk production, and nutrient digestibility. Treatments were 42 or 35% NFC and 0 or 3 g...

The K+-insensitive component of Mg2+ influx in primary culture of ruminal epithelial cells (REC) was examined by means of fluorescence techniques. The effects of extracellular anions, ruminal fermentation products, and transport inhibitors on the intracellular free Mg2+ concentration ([Mg2+]i), Mg2+ uptake, and intracellular pH were determined. Under control conditions (HEPES-buffered high-NaCl...

Maximizing milk yield without impairing host health is a great challenge for dairy industry. However, the high concentrate feeding often unavoidably increases the risk of Subacute ruminal acidosis (SARA) in dairy cows, characterized by periodic episodes of low ruminal pH. The economic costs caused by SARA are enormous, while its pathogenesis is not very clear. As the first and the main digestiv...

Feeding dairy cows for maximum milk production increases the risk of ruminal acidosis. Diets fed to high producing dairy cows in North America are typically highly digestible in the rumen and often lack sufficient physical fiber. Rapid fermentation of carbohydrates causes an accumulation of volatile fatty acids (VFA) in the rumen, leading to a drop in ruminal pH. Lack of sufficient physical fib...