The activities of phosphoenolpyruvate carboxykinase, ;malic enzyme', citrate-cleavage enzyme and glucose 6-phosphate dehydrogenase were assayed in homogenates of rumen mucosa, liver and adipose tissue of cattle. Rumen mucosa cytoplasm contained activities of ;malic enzyme' approximately sevenfold those of phosphoenolpyruvate carboxykinase, suggesting that the conversion of propionate into lacta...

It is well known that rumen fermentation processes play a key role in ruminant nutrition, as it is this distinctive symbiotic feature between the host and the rumen microflora that lends the ruminant animal several advantages in digestive and metabolic processes over non-ruminants. The extent of complexity of interactions between diverse groups of microorganisms which inhabit the rumen is such ...

1. Four sheep, each fitted with a rumen fistula and a re-entrant cannula at the proximal duodenum were fed a semi-purified diet containing urea as the only nitrogen source. The quantities of total protozoal amino acid-N (TPAN) present in the rumen and entering the duodenum were determined when the mean rumen dilution rate (D) was low (0.034/h) and when D was increased to 0.078/h by the intrarum...

Monitoring rumen conditions in cows is important because a dysfunctional rumen system may cause death. Sub-acute ruminal acidosis (SARA) is a typical disease in cows, and is characterized by repeated periods of low ruminal pH. SARA is regarded as a trigger for rumen atony, rumenitis, and abomasal displacement, which may cause death. In previous studies, rumen conditions were evaluated by wirele...

Two rumen protozoa vaccine formulations containing either whole fixed Entodinium or mixed rumen protozoa cells were tested on Merino sheep with the aim of decreasing the number and/or activity of protozoa in the rumen. Negative control (no antigen) and positive control (Tetrahymena corlissi antigens) treatments were also included in the experiment. Blood and saliva were sampled to measure the s...

Increasing awareness of hazards associated with the use of antibiotic and chemical feed additives has accelerated investigations into plants and their extracts as feed additives. The present review mainly discusses two classes of plant secondary compounds in this context, i.e. essential oils and saponins. The broader potential of plants and their extracts is illustrated by the progress of an EC...

Protozoa-associated methanogens (PAM) are considered one of the most active communities in the rumen methanogenesis. This experiment investigated whether methanogens are sequestrated within rumen protozoa, and structural differences between rumen free-living methanogens and PAM. Rumen protozoa were harvested from totally faunated sheep, and six protozoal fractions (plus free-living microorganis...

Rumen is a persistent and specific ecosystem consists of bacteria, protozoa and fungus where feed fermentation takes place in it. Produced Hydrogen in rumen can be used in the synthesis of the volatile fatty acids and the microbial protein and its excess would be eliminated through the production of Methane by methanogenesis. Nutritionists have tried to find ways to decrease loss and energy and...

The aim of the present experiment was to test the hypothesis that oral manipulation of feed is a behavioural need in cattle, irrespective of actual rumen load. Twelve rumen fistulated cows were used and subjected to four different treatments: low rumen content+long duration of eating (A), high rumen content+short duration of eating (B), high rumen content+long duration of eating (=positive cont...

Succinic acid is a major end product of two cellulose-fermenting bacteria isolated in pure culture from the rumen of cattle and sheep. Ruminococcus flavefaciens, isolated by Sijpesteijn (1948, 1949, 1951), produced some 0-5 m-mole succinic acid per m-mole cellulose (calculated as glucose) fermented. Bacteroides succinogenes, isolated from the bovine rumen by Hungate (1950), was found by this au...