Two experiments using six rumen-fistulated Holstein steers in 3 X 3 Latin square designs were conducted to test the effects of urea addition to corn silage, and grain addition to haylage, on feed intake, digestibility of nutrients and rumen fermentation of complete diets fed once daily. Addition of .34 and .68% urea to corn silage increased dietary crude protein from 8.1 to 11.3 and 13.3%, and ...

OBJECTIVE To determine the prevalence of subacute rumen acidosis (SARA) in beef cattle grazing lush pasture and the effect of monensin on reducing SARA and improving animal performance. DESIGN Commercial Angus and Murray Grey steers received a monensin slow-release capsule (n = 19) or remained untreated (n = 19). Cattle grazed an oats crop or tetraploid ryegrass pasture for a total of 91 days...

We used RNA probes and enzyme activities to compare the cellulolytic microbial ecosystems of the rumen and the cecum. Four rumen- and cecum-cannulated wethers were fed a diet of barley plus hay (60:40). Digesta samples were collected 1 h before feeding and 3, 6, and 9 h after feeding for measurements on microbial populations, and 1 h before feeding and 3 and 6 h after feeding for digestion meas...

The aim of this experiment was to study the effect of breed (Churra and Merino) and advancing season (middle June, late July and early October) on rumen fermentation in sheep grazing a continuously stocked grass /white clover pasture. Six mature sheep (three Churra and three Merino) fitted with rumen cannulae were used. During each grazing period, samples of the grazed herbage (obtained using t...

STEVENS, C. E., AND B. K. STETTLER. Factors affecting the transport of volatile fatty acids across rumen epithelium. Am. J. Physiol. 2 IO(~) : 365-372. I g66.-Isolated, short-circuited rumen epithelium was used to study the effects of pH, concentration gradient, imidazole vs. bicarbonate-buffer systems, and fatty acid metabolism on the transport of volatile fa tty acid. Transport of acetate a n...

Lactobacilli are employed in probiotic food preparations and as feed additives in poultry and livestock, due to health benefits associated with their consumption. The objective of this study was to evaluate and compare the probiotic potential of ten lactobacilli strains isolated from commercial dairy food products and animal rumen contents in New Zealand. Genetic identification of the isolates ...

Butyrate, a major rumen VFA, has been indirectly linked to enhancement of urea recycling on the basis of increased expression of urea transporter in the rumen epithelia of steers fed a rumen butyrate-enhancing diet. Two studies were conducted to quantify the effect of elevated rumen butyrate concentrations on N balance, urea kinetics and rumen epithelial proliferation. Wether sheep (n= 4), fitt...

This study was conducted to investigate the effects of feeding increasing proportions of corn grain on concentration of lipopolysaccharide (LPS) in the rumen fluid and the subsequent alterations in immune responses as reflected by plasma concentrations of serum amyloid A (SAA) and haptoglobin (Hp) in goats. Nine goats were assigned to three diets (0%, 25%, and 50% corn grain) in a 3 ×3 Latin sq...

Effects of two microbial feed supplements on microbial activities in rumen-stimulating cultures and the rumens of steers fed a fescue hay-based roughage diet were evaluated. The yeast culture supplement contained Saccharomyces cerevisiae (1.4 to 4.2 x 10(9) colony-forming units [cfu]/g), whereas the mixed microbial supplement contained yeast, lactobacilli and enterococci (1.4 to 2.7 x 10(9) cfu...

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...