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.

Ureolytic bacteria are key organisms in the rumen producing urease enzymes to catalyze the breakdown of urea to ammonia for the synthesis of microbial protein. However, little is known about the diversity and distribution of rumen ureolytic microorganisms. The urease gene (ureC) has been the target gene of choice for analysis of the urea-degrading microorganisms in various environments. In this...

It is now generally accepted that the fermentation of carbohydrates in the rumen gives rise to the formation of large amounts of the lower volatile fatty acids; but the fact that these acids are absorbed in considerable amounts and at different rates from the rumen into the blood stream has made it clear that in vitro studies of the fermentation processes are necessary in order to ascertain the...

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...

UNLABELLED To study the effects of an extract of plant flavonoids [Bioflavex (FL)] in cattle fed high-concentrate diets, 2 experiments were designed. In the first experiment, the effects of Bioflavex on the development of rumen acidosis was evaluated in 8 Holstein-Friesian crossbreed heifers (451 kg; SEM 14.3 kg of BW) using a crossover design. Each experimental period lasted 22 d; from d 1 to ...

Remote rumen temperature monitoring is a potential method for early disease detection in beef cattle. This experiment was conducted to determine if remotely monitored rumen temperature boluses could detect a temperature change in steers exposed to bovine viral diarrhea virus (BVDV) and challenged with a common bovine respiratory disease pathogen, Mannheimia haemolytica (MH). Twenty-four Angus c...

The objective of this experiment was to examine the effects of concentrates in feed, differing in carbohydrate source, on the rumen development of veal calves. For this purpose, 160 male Holstein Friesian x Dutch Friesian crossbred calves were used in a complete randomized block design with a 5 x 2 factorial arrangement. Dietary treatments consisted of 1) a milk replacer control, 2) a pectin-ba...

Molecular microbial ecology techniques are widely used to study the composition of the rumen microbiota and to increase understanding of the roles they play. Therefore, sampling and DNA extraction methods that result in adequate yields of microbial DNA that also accurately represents the microbial community are crucial. Fifteen different methods were used to extract DNA from cow and sheep rumen...

The present study was conducted to determine the effect of feed intake on the composition of the rumen contents of sheep and on their bacterial densities. Whole rumen contents were sampled after a period of continuous inter-rumen infusion of 15NH3 from four rumen-cannulated wethers successively fed on a hay-concentrate diet (2:1, w/w on a DM basis) at two rates of feed intake: 40 and 80 g DM/kg...

The aim of the present study was to describe age-related changes in anatomic, functional and microbial variables during the rumen development process, as affected by the feeding system (supplemental feeding v. grazing), in goats. Goats were slaughtered at seven time points that were selected to reflect the non-rumination (0, 7 and 14 d), transition (28 and 42 d) and rumination (56 and 70 d) pha...