Four multiparous lactating Holstein cows fitted with rumen cannulae were fed diets varying in the amount and source of rumen-degradable carbohydrates (starch vs. sucrose) to examine their effects on rumen fermentation, nitrogen metabolism and lactation performance. A 4×4 Latin square with four diets and four periods of 28 days each was employed. Corn starch and sucrose were added to diets and c...

Ammonia is an abundant fermentation product in the forestomachs of ruminants and the intestine of other species. Uptake as NH3 or NH4+ should modulate cytosolic pH and sodium-proton exchange via Na+/H+ exchanger (NHE). Transport rates of Na+, NH4+, and NH3 across the isolated rumen epithelium were studied at various luminal ammonia concentrations and pH values using the Ussing chamber method. T...

The effects of direct-cut and wilted silage with or without rapeseed meal (RSM) supplementation on rumen fermentation and digesta passage rates were studied in a 4 4 balanced Latin square experiment with four multiparous cows. The dry matter (DM) and crude protein (CP) degradabilities of silages were determined in sacco. RSM supplementation replaced 16% of the oat±barley concentrate mixture. Th...

SARA is a common and serious problem in well-managed and intensive dairy herds or beef cattle operations, because of triggering other metabolic disorders and causing lactation-fertility losses. It is a metabolic disease in dairy cattle that occurs during early and mid-lactation and has traditionally been characterized by low rumen pH, but lactic acid does not accumulate as in acute lactic acid ...

1. Three sheep fitted with rumen cannulas were fed hourly a daily ration of 1000 g pelleted-grass cubes, and during four successive 2-week periods were intraruminally infused (0.45 l/d) with solutions containing sodium chloride (0.47 mol/d), sodium bicarbonate (0.47 mol/d), .ammonium chloride (0.47 mol/d) and sodium butyrate (0.47 mol/d). Each solution, except that for NaHCO,, was adjusted to p...

Third-cutting alfalfa with 37% DM was ensiled untreated or treated with either 2.8 g of formic acid/100 g of DM or .31 g of formaldehyde/100 g of DM and fed to lactating dairy cows in two experiments. Silage treated with formic acid had the lowest pH and concentrations of NPN, NH3, and total free AA. Both treatments decreased rumen in vitro protein degradability but did not affect in vitro rume...

The molecular mechanisms underlying rumen epithelial adaption to high-grain (HG) diets are unknown. To gain insight into the metabolic mechanisms governing epithelial adaptation, mature nonlactating dairy cattle (n = 4) were transitioned from a high-forage diet (HF, 0% grain) to an HG diet (65% grain). After the cattle were fed the HG diet for 3 wk, they returned to the original HF diet, which ...

OBJECTIVE The aim of the study was to isolate gossypol-degrading bacteria and to assess its potential for gossypol degradation. METHODS Rumen liquid was collected from fistulated cows grazing the experimental pasture. Approximately 1 mL of the rumen liquid was spread onto basal medium plates containing 2 g/L gossypol as the only source of carbon and was then cultured at 39°C to isolate gossyp...

In a 148-d feedlot experiment, 48 crossbred steers were fed a 70% sorghum diet with clinoptilolite (CLN), a natural zeolite, substituted at 0, 1.25 and 2.5% of the diet dry matter. No differences (P>.05) were detected in average daily gain, feed intake (dry matter and organic matter) and feed efficiency among treatments. Negative correlations (P<.05) between fecal starch and fecal pH were detec...