The rumen microbiome is integral to efficient production in cattle and shows strong host specificity, yet little is known about what host factors shape rumen microbial composition. Secretory immunoglobulin A (SIgA) is produced in large amounts in the saliva, can coat both commensal and pathogenic microbes within the gut, and presents a plausible mechanism of host specificity. However, the role ...

Cattle manure is frequently used as an inoculum for the start-up of agricultural biogas plants or as a co-substrate in the anaerobic digestion of lignocellulosic feedstock. Ruminal microbiota are considered to be effective plant fiber degraders, but the microbes contained in manure do not necessarily reflect the rumen microbiome. The aim of this study was to compare the microbial community comp...

Four non-lactating, rumen-fistulated cows were fed ad lib. on two grass silages (first cut (FC) and second cut (SC) harvested at different growth stages, resulting in different crude-protein (CP) and neutral-detergent-fibre (NDF) contents (FC, 152g CP/kg, 515g NDF/kg and SC, 210g CP/kg, 442g NDF/kg). Voluntary intake and rumen contents, total as well as organic matter were higher for silage FC....

A semi-synthetic thiamine-free diet was used on weaned lambs to test the effect of a high sulfur level on the rumen, microbial activity and on the microbial production of thiamine. In vivo and in vitro kinetic studies, as well as the determination of the thiamine concentrations and thiaminase activity in the rumen, were performed during the 16 week experiment. A high sulfur level (0.6%) in the ...

BACKGROUND Ureolytic activity of rumen bacteria leads to rapid urea conversion to ammonia in the rumen of dairy cows, resulting possible toxicity, excessive ammonia excretion to the environment, and poor nitrogen utilization. The present study investigated immunization of dairy cows against urease in the rumen as an approach to mitigate bacterial ureolytic activity therein. RESULTS Most alpha...

Our objective was to evaluate a near-infrared reflectance spectroscopy (NIRS) used in the feed industry to estimate the potential for grains to increase the risk of ruminal acidosis. The existing NIRS calibration was developed from in sacco and in vitro measures in cattle and grain chemical composition measurements. To evaluate the existing model, 20 cultivars of 5 grain types were fed to 40 Ho...

Members of the domain Archaea contribute about 0.3 to 3.3% of the microbial small subunit (16S and 18S) rRNA in the rumen (22, 39, 60). Archaea have a range of different metabolisms and are found in many habitats (6), but those known to exist in the rumen are strictly anaerobic methanogens. Yanagita et al. (59) observed that 2.8 to 4.0% of ruminal microorganisms displayed autofluorescence chara...

ruminal bacteria and protozoa provide excellent organic phosphorus (p) sources for the host animal. this experiment was conducted to compare the bioavailability of bacterial and protozoal p in comparison with that of dicalcium phosphate (dcp) as a reference phosphorus source. bacteria and protozoa were isolated from the rumen contents of dairy cows and the chick-model was used to determine the ...

Ruminants in tropical and desert areas routinely experience cycles of severe dehydration and rapid rehydration. These animals can withstand severe dehydration (18-40% of initial body weight), which exceeds considerably the capacity of most monogastric mammals. This capacity is related to their ability to use, during the course of dehydration, their large water reservoir in the rumen, which cont...

Isotopic tracer experiments were conducted in vitro to determine contribution of protozoa toward the biosynthesis of lysine in the rumen microbial ecosystem. The presence of protozoa in a rumen microbial suspension always increased lysine synthesis from aspartate. Rumen contents from a faunated goat produced a higher amount of lysine than did those from a defaunated one.