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At least 109 records · Page 6Linked to original sources

Forage intake, ruminal dry matter disappearance, and ruminal blood volatile fatty acids for steers in 18 and 32 degrees C temperatures.

Six steers with rumen cannulas and exteriorized carotid arteries were fed chopped alfalfa, orchardgrass, or tall fescue hay in ambient temperatures (18 and 32 degrees C) using a factorial arrangement of forage and temperature with repeated measurements. Arterial blood, venous blood, and rumen fluid were sampled for VFA at 0, 2, 4, and 7 h after forage was offered. Rate of digestion of plant cell wall was determined by in vitro methods. Rate of ingesta and particulate passage was determined by 144Ce marker. Volatile fatty acid concentrations in blood plasma and rumen fluid were not related to forage voluntary intake. Voluntary forage intake was related to calculated ruminal disappearance of cell wall (r2 of .94). Elevated ambient temperature, 32 degrees C, depressed voluntary forage intake but did not increase ruminal or blood VFA concentrations.

Animal Feed↗

Lactation response to ruminally protected methionine and lysine at two amounts of ruminally available nitrogen.

Sixty multiparous Holsteins were used in a 200-d continuous lactation trial designed to measure the response to a mixture of ruminally protected Met and Lys. Response to AA was determined at two dietary concentrations of degraded protein designed to provide 85 and 100% of NRC recommended amounts. This difference in degraded protein content was achieved by addition of urea. Diets without urea supported lactation as well as diets with added urea in early lactation. In midlactation, urea addition was detrimental to yields of milk and milk protein; addition of AA prevented this negative effect. In early lactation, AA addition raised milk protein concentration and yield by 1 g/kg of milk of 37 g/d and did not interact with urea. Increases in protein concentration in response to AA addition were similar in early and late lactation and corresponded to changes in the casein fraction of milk. These results support previous work showing the importance of adequate absorbable Lys and Met to maximize the protein content of milk. The results suggest that interactions may occur between ruminal ammonia production and AA supply.

Ammonia↗

Internal vomiting in the ruminant: effect of apomorphine on ruminal pH in sheep.

Five sheep, with a rumen fistula inserted, were each injected (IV) with apomorphine (18 mg) and ruminal pH was measured every 5 minutes during a 1-hour period. During the base-line period (30 minutes) that preceded apomorphine injection, pH was constant in individual sheep and te group mean (+/- SD) was 7.1 +/- 0.35. After apomorphine was injected, group mean was 6.9, 6.0, 6.3, 6.3, 6.3, 6.4, 6.4, 6.5, 6.7, 6.9, 6.9, and 7.1 at 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, and 60 minutes, respectively. The pH reduction of ruminal content was recorded in 4 of the sheep. Maximal reduction occurred in the 10-minute period after apomorphine was injected. The pH returned to control value within 40 to 50 minutes after injection. Vomitus was not expelled through the mouth by any of the sheep. It was concluded that expulsion of acidic abomasal contents back into the preabomasal compartment (internal vomiting) was the cause of acidification of the rumen after apomorphine was injected.

Animals↗

Fermentation of cellulose and production of cellulolytic and xylanolytic enzymes by anaerobic fungi from ruminant and non-ruminant herbivores.

Four anaerobic fungi were grown on filter paper cellulose and monitored over a 7-8 days period for substrate utilisation, fermentation products, and secretion of cellulolytic and xylanolytic enzymes. Two of the fungi (N1 and N2) were Neocallimastix species isolated from a ruminant (sheep) and the other two fungi were Piromyces species (E2 and R1) isolated from an Indian Elephant and an Indian Rhinoceros, respectively. The tested anaerobic fungi degraded the filter paper cellulose almost completely and estimated cellulose digestion rates were 0.25, 0.13, 0.21 and 0.18 g.l-1.h-1 for strains E2, N1, N2, R1, respectively. All strains secreted cellulolytic and xylanolytic enzymes, including endoglucanase, exoglucanase, beta-glucosidase and xylanase. Strain E2 secreted the highest levels of enzymes in a relatively short time. The product formation on avicel by enzymes secreted by the four fungi was studied. Both in the presence and absence of glucurono-1,5-delta-lactone, a specific inhibitor of beta-glucosidase, mainly glucose was formed but no cellobiose. Therefore the exoglucanase secreted by the four fungi is probably a glucohydrolase.

Anaerobiosis↗

The activities of 2-oxoglutarate dehydrogenase and pyruvate dehydrogenase in hearts and mammary glands from ruminants and non-ruminants.

1. The activities of 2-oxoglutarate dehydrogenase (EC 1.2.4.2) were measured in hearts and mammary glands of rats, mice, rabbits, guinea pigs, cows, sheep, goats and in the flight muscles of several Hymenoptera. 2. The activity of 2-oxoglutarate dehydrogenase was similar to the maximum flux through the tricarboxylic acid cycle in vivo. Therefore measuring the activity of this enzyme may provide a simple method for estimating the maximum flux through the cycle for comparative investigations. 3. The activities of pyruvate dehydrogenase (EC 1.2.4.1) in mammalian hearts were similar to those of 2-oxoglutarate dehydrogenase, suggesting that in these tissues the tricarboxylic acid cycle can be supplied (under some conditions) by acetyl-CoA derived from pyruvate alone. 4. In the lactating mammary glands of the rat and mouse, the activities of pyruvate dehydrogenase exceeded those of 2-oxoglutarate dehydrogenase, reflecting a flux of pyruvate to acetyl-CoA for fatty acid synthesis in addition to that of oxidation via the tricarboxylic acid cycle. In ruminant mammary glands the activities of pyruvate dehydrogenase were similar to those of 2-oxoglutarate dehydrogenase, reflecting the absence of a significant flux of pyruvate to fatty acids in these tissues.

Acetyl Coenzyme A↗

Comparison of ruminal and post-ruminal digestion of a concentrate feed in the young calf.

Pre-ruminant calves were pair-fed a concentrate feed in either liquid form (LC) from a nipple bottle or in dry form (DC). We then studied the effects of these two forms of feed on body weight gain, feed utilization, digestibility, digestive enzyme secretion and volatile fatty acids in the rumen liquor. The live weight gain of calves receiving the liquid concentrate was depressed by 34 p. 100. The digestibility of total dry matter, protein, starch and energy was lower in the LC than in the DC group. The daily amounts of trypsin, chymotrypsin and amylase excreted in the faeces were similar in both groups. Lipase secretion was significantly increased in the LC group. Due to a 2.7-fold increase in the amount of faeces excreted, faecal digestive enzyme concentration was depressed in the LC group. Feeding dry concentrate to young calves reduced the pH in the rumen liquor and markedly increased the concentration of volatile fatty acids, especially C2, C3 and C4. The processes occurring in the rumen increased the digestibility of the concentrate protein by about 60 p. 100 and that of starch by 20 p. 100.

Amylases↗

[Consumption and ruminating behavior in sheep. 5. Continuous registration and recording of consumption and rumination dependent jaw movements in sheep based on acceleration measurements].

A method of the registration of the feed intake and ruminating behaviour of sheep which uses piezoelectric converters was tested. The appliance-technological solution and the feasibility and routine measurings are described. It showed that measurings on the basis of acceleration registration produced similar results as the 'halter method with plate feelers' used so far and that disturbance of the test animals is reduced.

Animal Feed↗

Isolation and characterization of a bacteriocin (Butyrivibriocin AR10) from the ruminal anaerobe Butyrivibrio fibrisolvens AR10: evidence in support of the widespread occurrence of bacteriocin-like activity among ruminal isolates of B. fibrisolvens.

Forty-nine isolates of Butyrivibrio fibrisolvens and a single isolate of Butyrivibrio crossotus were screened for the production of inhibitors by a deferred plating procedure. Twenty-five isolates produced factors which, to various degrees, inhibited the growth of the other Butyrivibrio isolates. None of the inhibitory activity was due to bacteriophages. The inhibitory products from 18 of the producing strains were sensitive to protease digestion. Differences in the ranges of activity among the Butyrivibrio isolates and protease sensitivity profiles suggest that a number of different inhibitory compounds are produced. These findings suggest that the production of bacteriocin-like inhibitors may be a widespread characteristic throughout the genus Butyrivibrio. The bacteriocin-like activity from one isolate, B. fibrisolvens AR10, was purified and confirmed to reside in a single peptide. Crude bacteriocin extracts were prepared by ammonium sulfate and methanol precipitation of spent culture supernatants, followed by dialysis and high-speed centrifugation. The active component was isolated from the semicrude extract by reverse-phase chromatography. Tricine-sodium dodecyl sulfate-polyacrylamide gel electrophoresis confirmed that the peptide was purified to homogeneity, having an estimated molecular mass of approximately 4,000 Da. The N terminus of the peptide was blocked. A cyanogen bromide cleavage fragment of the native peptide yielded a sequence of 20 amino acids [(M)GIQLAPAXYQDIVNXVAAG]. No homology with previously reported bacteriocins was found. Butyrivibriocin AR10 represents the first bacteriocin isolated from a ruminal anaerobe.

Amino Acid Sequence↗

[An in-vitro method of ruminal juice cultivation, suitable for the comparison of various sources of nonprotein nitrogen for ruminants].

The method of cultivating rumen fluid in buffer with nutrient admixture under CO2 atmosphere is described. The method serves for the comparison and description of the properties of NPN sources for ruminants. Its applicability is demonstrated on the example of urea. During incubation, all parameters of the medium remain within an admissible range. Considering the analyses of the incubation medium, i. e. determination of the pH value, ammonia, urea, volatile fatty acids, total protein, and redox potential, it is recommended to monitor the course of fermentation for six hours and to take samples in the intervals of 0, 1, 2, 4 and 6 hours.

Animal Feed↗

A sandwich-ELISA for the diagnosis of Peste des petits ruminants (PPR) infection in small ruminants using anti-nucleocapsid protein monoclonal antibody.

A sandwich ELISA test using PPR specific monoclonal antibody (clone 4G6) to an epitope of nucleocapsid protein has been developed. The test uses polyclonal sera to capture the antigen from clinical samples (swabs and tissues). Captured antigens from clinical samples are detected using PPR specific monoclonal antibody. The test is specific to PPR as it failed to detect rinderpest vaccine virus (RBOK strain). Varieties of clinical samples originating from laboratory experiments (n = 231) and from field (n = 259) were employed to test the efficacy of sandwich-ELISA test. The test compared very well with an internationally accepted commercial Immune-capture ELISA kit, which uses biotinylated monoclonal antibody against the nucleocapsid protein. On a parallel testing using 490 clinical samples, 4G6 MAb based sandwich ELISA had an overall relative diagnostic specificity of 92.8% and diagnostic sensitivity of 88.9% compared to the commercial kit. The newly developed test is free from prozone phenomenon. PPR outbreaks from various parts of India have been confirmed using the test. Findings suggested that the newly developed ELISA is suitable for PPR diagnosis under field conditions.

Animals↗