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SUMMARYA technique is described for thein vivoestimation of the rate of production of bacteria in the rumen of buffalo calves. The animals were given their daily ration in 12 equal amounts at 2-h intervals. The bacterial cells from the rumen were labelled either with14C or36S byin vitroincubation in the presence of [U-14C]DL-leucine or35S-sodium sulphate. Labelled bacterial cells were injected in a single dose into the rumen. Samples of the ruminal fluid were drawn at various time intervals for 9 h and the specific radio-activity of the bacteria determined. The dilution in the specific radioactivity was used to calculate the turn-over time and rates of production of bacteria in the rumen. The average turnover time was 308 min. The production rate of bacteria averaged 211 mg/min (20·3 g/mole VFA produced).

SummaryThe rate of production of bacteria in the rumen of buffalo calves kept on two rations was measured using14C labelledStreptococcus bovisand35S whole ruminal bacterial cells. The animals received daily either 15–20 kg green maize or 25–30 kg green cow pea in 12 equal amounts at 2-h intervals. The bacterial cells from the rumen of animals maintained on the same diet were tagged with35S byin vitroincubation in the presence of35S-sodium sulphate. SimilarlyStreptococcus bovisof rumen origin was grown in the presence of U-14C dl-leucine. The cells were injected into the rumen in a single dose. The dilution of the specific radioactivity of bacterial cells in the rumen with time was taken for calculation of the turnover time and rate of production of bacteria.The average production rates of bacteria were 88·3 ± 3·88 and 92·3 ± 1·82 g/kg digestible organic matter and 101·8 ± 1·55 and 103·3 ± 1·49 g/kg digestible organic matter in animals fed green maize and cow pea, when estimated by using mixed rumen whole bacterial cells andStreptococcus bovisrespectively. There was no significant difference in the rate of bacteria production when estimated by either method.

The relative efficiency of voluntary consumption, chemical composition, digestibility in vitro and in vivo, was tested for predicting the nutritive value of five forages: berseem (Trifolium alexandrinum); green oat (Avena sativa); oat hay; cow pea (Vigna spp.) and maize (Zea mays). The digestibility coefficients of dry matter (DM), crude protein, acid-detergent lignin and energy were significantly correlated with DM intake. Digestibilities in vitro of DM and cellulose after 12-h incubation were significantly related to digestibilities in vivo of DM and energy. The values for cellulose digestibility in vitro at 24 h were similar to those for digestibility of energy in vivo. Significant correlations were obtained between the crude protein content of forages and the voluntary DM intake and digestibility of nutrients. Increased cellulose and acid-detergent fibre contents were each related with decreased DM intake and digestibility of nutrients.

SummaryExperiments were conducted on 12 male growing calves of zebu cattle (Bos indicus) and buffalo (Bos bubalis) to study the effect of feeding wheat straw presoaked with water on the voluntary feed intake, digestibility coefficients of nutrients and volatile fatty acid concentration and production. The feed intake was improved significantly (P < 0·05) in both the species as a result of soaking. The digestibility of crude protein and crude fibre was depressed (P < 0·05), whereas the nitrogen-free extract utilization increased significantly (P < 0·01) on soaking of straw. The availability of digestible energy and metabolizable energy was also more as a result of water treatment of wheat straw. The production rates of total volatile fatty acids and acetic acid were higher in both the species fed on water-soaked wheat straw. It is concluded that pre-soaking of wheat straw for 1–2 h with ordinary tap water may give an overall beneficial effect in both zebu and buffalo calves.

SUMMARYThe digestibility of protein of mixed whole rumen bacterial cells and Streptococcus bovis were determined in Bos bubalis and goats. The bacterial cells were labelled either with 35S or 14C in vitro incubation and were injected in a single dose into the rumen after protecting by formaldehyde treatment. Faeces were collected for 6 consecutive days and radioactivity excreted in the faeces was measured. The digestibility of bacterial protein ranged from 81·7 to 96·8% in both the species.

SummaryThe production rates of bacteria have been measured in the rumen of zebu calves and buffalo calves. The animals were fed green oat continuously at 2 h intervals. [35S]sodium sulphate was fed to the animals for 5 days at 2 h intervals by mixing in the feed. On the sixth day the radioactive feed was stopped and replaced by non-radioactive feed. The decline in the specific radioactivity of bacterial cells in the rumen as a function of time was taken for calculatingt/2. Simultaneously rumen volume was determined and pool size of bacterial cells was calculated in the rumen. A mathematical equation was applied to calculate the production rates of bacteria. The production rates of bacteria, on average, were 100·5 and 72·3 mg/min for buffalo calves and zebu calves, respectively.