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...

In vitro studies with isolated sheep rumen epithelium have shown that an increase in the lumen K concentration induces an increase in the transmural potential difference across the rumen epithelium (serosal side: positive), which is associated with a decrease in Mg transport. However, at lumen K concentrations >80 mmol/l, Mg transport across the epithelium became independent of the lumen K conc...

Ergot alkaloids in endophyte-infected (Neotyphodium coenophialum) tall fescue (Lolium arundinaceum) have been shown to cause a reduction in blood flow to the rumen epithelium as well as a decrease in volatile fatty acids (VFA) absorption from the washed rumen of steers. Previous data also indicates that incubating an extract of endophyte-infected tall fescue seed causes an increase in the amoun...

Active Na+ absorption across rumen epithelium comprises Na+/H+ exchange and a nonselective cation conductance (NSCC). Luminal chloride is able to stimulate Na+ absorption, which has been attributed to an interaction between Cl-/HCO3- and Na+/H+ exchangers. However, isolated rumen epithelial cells also express a Cl- conductance. We investigated whether Cl- has an additional effect on electrogeni...

1. The activities of acetoacetyl-CoA thiolase, hydroxymethylglutaryl-CoA synthase and lyase and acetoacetyl-CoA deacylase were measured in homogenates of samples of liver, rumen epithelium (long papillae), kidney and lactating mammary gland derived from slaughtered cows. 2. The activities of the four enzymes in bovine liver were similar to the activities previously reported for the correspondin...

Label-MMAcid-Rev030410 BACKGROUND Ruminants are animals that have multiple stomachs to allow consumption and digestion of fibrous feedstuffs. Key to this digestive process is the bacterial breakdown of the fiber in the first stomach or rumen. The bacterial balance in the rumen can shift, allowing the ruminant to adapt to different diets. Ruminal bacteria convert fiber into lactate and volatile ...

Schweigel, Monika, Ingo Lang, and Holger Martens. Mg21 transport in sheep rumen epithelium: evidence for an electrodiffusive uptake mechanism. Am. J. Physiol. 277 (Gastrointest. Liver Physiol. 40): G976–G982, 1999.—The potential difference (PD)-dependent component of transcellular Mg21 uptake in sheep rumen epithelium was studied. Unidirectional 28Mg21 fluxes were measured at various transepith...

Background. Ruminants are successful herbivorous mammals, in part due to their specialized forestomachs, the rumen complex, which facilitates the conversion of feed to soluble nutrients by micro-organisms. Is the rumen complex a modified stomach expressing new epithelial (cornification) and metabolic programs, or a specialised stratified epithelium that has acquired new metabolic activities, po...

Fifteen cross-bred male lambs (Dorset × Small Tail Han), aged 7 weeks, with average liveweight of 13.8±0.8 kg, were used to study effects of feeding mixed volatile fatty acid (VFA) sodium salt on insulin-like growth factor-I (IGF-I), insulin-like growth factor-binding protein-3 (IGFBP-3) in plasma and rumen tissue and rumen epithelium development. The lambs were randomly divided into 5 groups w...