Colony counts which approximated those in a habitat-simulating, rumen fluid-agar medium (RFM) were obtained in medium 10, a medium identical to the RFM except for the replacement of rumen fluid with 1.5 x 10(-6)m hemin, 0.2% Trypticase, 0.05% yeast extract, and a 6.6 x 10(-2)m volatile fatty acid mixture qualitatively and quantitatively similar to that in rumen fluid. Single deletion of Tryptic...

In vitro experiments were conducted to study the permeabil i ty to thiamin of sheep rumen wall in either direction. Isolated discs of rumen wall mucosa were used in incubation experiments over 3 hr, controlled by measurements of transmural potentials. In some experiments 14 C-labeled thiamin was used. At thiamin concentrations in the mucosal fluid ranging from .1 to 1.6/ag/ml no changes of the ...

A new rumen escapable tool is presented for cattle in prospect of developing medical treatment or supplementing trace elements for disease prevention. This tool consists of a three-layered capsule that dissolves in the lower digestive tract, but not in the rumen. The capsule was manufactured by capsule-forming techniques through the use of liquid surface tension. This method does not involve hi...

A mature dairy cow was transitioned from a high forage (100% forage) to a high-grain (79% grain) diet over seven days. Continuous ruminal pH recordings were utilized to diagnose the severity of ruminal acidosis. Additionally, blood and rumen papillae biopsies were collected to describe the structural and functional adaptations of the rumen epithelium. On the final day of the grain challenge, th...

Volatile organic compounds (VOCs) and odors in cattle rumen gas have been characterized by in-vivo headspace sampling by solid-phase microextraction (SPME) and analysis by gas chromatography-mass spectrometry-olfactometry (GC-MS-O). A novel device enabling headspace SPME (HS-SPME) sampling through a cannula was designed, refined, and used to collect rumen gas samples from steers. A Carboxen-pol...

The biohydrogenation (BH) theory represents a unifying concept to explain the basis for diet-induced milk fat depression (MFD) where unusual intermediates of ruminal fatty acid BH accumulate in the rumen and eventually reduce milk fat synthesis in the mammary gland. Under certain dietary situations the rumen environment is altered and a portion of BH occurs via a pathway that produces trans-10,...

In order to test the hypothesis that negative feedback signals from abdominal receptors are integrated in an additive manner in the control of voluntary food intake, cows with rumen fistulas were given intraruminal infusions of sodium acetate or sodium propionate, or both, with or without distension of the rumen by balloon. Intakes were monitored during the 3 h experimental period and for 2 h a...

This experiment was determined the effect of weaning time on growth performance, rumen fermentation, and microbial bacterial community of lambs. Forty eight Hu lambs were randomly divided into 4 treatments. Control lambs were ewereared (ER), while others were weaned at d 10, 20, or 30 after birth (EW10, EW20 and EW30) and fed milk replacer artificially until d 60. All lambs had ad libitum acces...

The ability of ruminants to utilize cellulosic biomass is a result of the metabolic activities of symbiotic microbial communities that reside in the rumen. To gain further insight into this complex microbial ecosystem, a selection-based batch culturing approach was used to identify candidate cellulose-utilizing bacterial consortia. Prior to culturing with cellulose, rumen contents sampled from ...

The urease (EC 3.5.1.5) inhibitor, phenylphosphoryldiamidate (PPDA), was given by continuous infusion into the rumen of two sheep nourished by intragastric infusion and into either the rumen or abomasum of four sheep given a pelleted diet containing 119 g crude protein (nitrogen x 6.25)/kg dry matter. PPDA was given at 1 g/d in infusion sheep and 1.5 g/d in the normally-fed sheep. Measurements ...