Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Ruminant”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,045 records · Page 58Linked to original sources
PubMed1997

The effect of nisin and monensin on ruminal fermentations In vitro.

When mixed ruminal bacteria and alfalfa were incubated in vitro, monensin and nisin both inhibited methane production so long as the concentrations were greater than 1 microM. Monensin- and nisin-dependent methane depressions caused a decrease in the acetate to propionate ratio (4.5 to 3.0). Total volatile fatty acid production was decreased by both monensin and nisin addition at concentrations greater than 2 microM. Starch-digesting ruminal bacteria were initially inhibited by monensin and nisin, but this effect disappeared after two to four transfers. Nisin always inhibited cellulolytic bacteria, but the nisin-dependent inhibition of cellulose digestion was no greater than the inhibition caused by monensin. Monensin and nisin also inhibited amino acid degradation, and nisin was more effective than monensin in controlling the growth of Clostridium aminophilum, an obligate amino acid-fermenting ruminal bacterium that can tolerate low concentrations of monensin. Because nisin was as potent as monensin, bacteriocins such as nisin may have potential as feed additives.

Acetates↗
PubMed1998

Effects of chlorhexidine diacetate on ruminal microorganisms.

The objectives of this study were to examine the effects of chlorhexidine diacetate on growth and L-lactate production by Streptococcus bovis JB1 as well as the effects of this antimicrobial compound on the mixed ruminal microorganism fermentation. Addition of 1.8 microM chlorhexidine diacetate to glucose medium resulted in a lag in growth by S. bovis JB1, and growth was completely inhibited in the presence of 3.6, 9.0, and 18 microM chlorhexidine. When 6.2 microM chlorhexidine diacetate was added to glucose medium after 2 h of incubation, glucose utilization and L-lactate production by S. bovis JB1 were reduced. Phosphoenolpyruvate-dependent phosphorylation of 14C-glucose by toluene-treated cells of S. bovis JB1 was inhibited by increasing concentrations (1.8 to 18 microM) of chlorhexidine, whereas only the 18 microM concentration reduced the membrane potential (delta psi). Chlorhexidine diacetate was a potent inhibitor of L-lactate and methane production from glucose fermentation by mixed ruminal microorganisms. However, because chlorhexidine also decreased acetate and propionate concentrations and increased ammonia concentrations in mixed-culture incubations, this antimicrobial compound may have limited application as a ruminant feed additive.

Animals↗
PubMed1999

The ability of "low G + C gram-positive" ruminal bacteria to resist monensin and counteract potassium depletion.

Gram-negative ruminal bacteria with an outer membrane are generally more resistant to the feed additive, monensin, than Gram-positive species, but some bacteria can adapt and increase their resistance. 16S rRNA sequencing indicates that a variety of ruminal bacteria are found in the "low G + C Gram-positive group," but some of these bacteria are monensin resistant and were previously described as Gram-negative species (e.g., Selenomonas ruminantium and Megasphaera elsdenii). The activity of monensin can be assayed by its ability to cause potassium loss, and results indicated that the amount of monensin needed to catalyze half maximal potassium depletion (K(d)) from low G + C gram-positive ruminal bacteria varied by as much as 130-fold. The K(d) values for Butyrivibrio fibrisolvens 49, Streptococcus bovis JB1, Clostridium aminophilum F, S. ruminantium HD4, and M. elsdenii B159 were 10, 65, 100, 1020, and 1330 nM monensin, respectively. B. fibrisolvens was very sensitive to monensin, and it did not adapt. S. bovis and C. aminophilum cultures that were transferred repeatedly with sub-lethal doses of monensin had higher K(d) values than unadapted cultures, but the K(d) was always less than 800 nM. S. ruminantium and M. elsdenii cells were highly resistant (K(d) > 1000 nM), and this resistance could be explained by the ability of these low G + C Gram-positive bacteria to synthesize outer membranes.

Anaerobiosis↗
PubMed2000

Isolation and identification of ruminal methanogens from grazing cattle.

To obtain information on the diversity of ruminal methanogens in grazing animals, three ruminal methanogens from grazing cattle were characterized and identified. Two of the isolates were rod-shaped, with one staining Gram-positive and being non-motile (BRM9), and the other (BRM16) staining Gram-negative and being motile. These isolates grew only on H(2)/CO(2) and formate, and optimally at 38 degrees C and pH 6.5-7.0. The third isolate (CM1) was non-motile, pseudosarcina-shaped, and grew on H(2)/CO(2), acetate, and methyl-containing compounds, with optimal growth at 40 degrees C and pH 6.5. DNA was prepared from the three isolates, and their 16S rRNA genes were sequenced. Phenotypic data and comparisons of nearly complete 16S rDNA sequences showed that BRM9, BRM16, and CM1 are strains of Methanobacterium formicicum, Methanomicrobium mobile, and Methanosarcina barkeri respectively. To the best of our knowledge, this is the first information on ruminal methanogens in cattle maintained under grazing management.

Animal Husbandry↗
PubMed1998

Generic relationship between calcium intake and radiostrontium transfer to the milk of dairy ruminants.

The hypothesis is tested that there is a generic relationship between the calcium intake and the transfer of radiostrontium to milk which can be used for all dairy ruminants. In addition to the daily calcium intake, the relationship also requires values for the strontium to calcium observed ratio, which describes the discrimination in transfer of the two elements to milk (a value of 0.11 is used), and the calcium concentration in milk. The relationship had previously only been validated for dairy cattle as there were insufficient data for other ruminant species. Here, we present recently available data for dairy goats, and also a limited amount of data for sheep derived from the literature. From the comparison between these data and predicted values, we conclude that it is possible to derive a generic model of the transfer of radiostrontium to the milk of dairy ruminants.

Animals↗
PubMed1982

Management of chronic rumination with a contingent exercise procedure employing topographically dissimilar behavior.

Walking was employed as a functionally incompatible activity in a contingent exercise procedure to manage chronic rumination in a 10 year old mentally retarded male. The high frequency ruminative behavior was rapidly reduced once the topographically dissimilar activity was introduced as a contingency. On the first day the contingent exercise procedure was used in conjunction with a differential reinforcement of other behavior (DRO) 30-sec schedule. Thereafter the contingent exercise was used alone. The ruminative behavior appeared to be under the control of the contingency and remained at essentially a zero rate during the 4 month extended observation period as well as throughout the 6 month follow-up.

Behavior Therapy↗
PubMed1987

Elimination of rumination by controlled eating and differential reinforcement.

The purpose of the present study was to examine the effectiveness of a controlled eating technique and a procedure which combined controlled eating with differential reinforcement of other behavior (DRO) for the reduction of rumination in an obese, 23-year-old, severely retarded and autistic male. The controlled eating technique resulted in a 75 per cent reduction in the rate of rumination while controlled eating with DRO resulted in an overall 95 per cent reduction. A six month follow-up showed that the participant's ruminative behavior had declined to zero.

Adult↗
PubMed1989

Behaviour therapy and obsessional ruminations: can failure be turned into success?

This paper considers the possible reasons for the relative failure of behavioural treatment for 'ruminations' (obsessional thoughts without overt compulsive behaviour). It is argued that this problem is due to an inadequate conceptualisation of the nature of ruminations and that as a result, exposure and response prevention have not been applied effectively. Effective treatment of ruminations requires systematically applied exposure in conjunction with the identification and prevention of covert compulsive behaviours. The practical problems of implementing 'covert exposure and response prevention' are considered and a form of habituation training is described, which is designed to overcome these inadequacies. A series of single case studies using this technique is presented.

Adult↗
PubMed1995

The rumination syndrome: clinical features rather than manometric diagnosis.

BACKGROUND/AIMS: Rumination is infrequent in adults of normal mental capacity. Upper gastrointestinal manometry reportedly confirms the diagnosis. Clinical characteristics, treatment(s), and outcomes of these patients are unclear. METHODS: We assessed 38 adults and adolescents with rumination between 1987 and 1994. Esophagogastroduodenal manometric recordings (n = 36; 3-hour fasting and 2-hour postprandially) were reviewed; follow-up information was obtained from mailed questionnaires. RESULTS: Patients saw a mean of five physicians and had symptoms for a mean of 2.75 years before diagnosis. Features included daily, effortless regurgitation of undigested food starting within minutes of meals. Weight loss was substantial (mean, 29 lb) in 42% of patients. Seventeen percent of female patients had a history of bulimia. Manometry confirmed the clinical diagnosis in 33% but was otherwise normal in all. Of 16 patients who responded to our questionnaires of 29 with > 6 months of follow-up (average, 35 months), 12 reported subjective improvement. In 14, the behavior persists. CONCLUSIONS: The rumination syndrome is underdiagnosed. With typical clinical features, gastroduodenal manometry seems unnecessary to confirm the diagnosis. Diagnosis and reassurance are important in management to avoid unnecessary tests and treatments.

Adolescent↗
PubMed1993

Influences of extracellular matrix components on the growth and differentiation of ruminal epithelial cells in primary culture.

Primary cultures of ovine ruminal epithelial cells were made to study the influence of collagen types I and IV out of medium supplementation with various hormones and Na-n-butyrate on cell morphology and growth characteristics. Both collagen type I and type IV led to increased cell proliferation with the stimulatory effect being more pronounced in collagen IV. In cultures grown on collagen I, both non-stratified and stratified colonies were found, whereas cultures grown on collagen IV showed predominantly stratified growth. Cells in both stratified and non-stratified colonies were positive for cytokeratin antibody. In non-stratified colonies, positive staining with fibronectin antibodies (FN-15) was found in a network over and around the cells. It is suggested that the non-stratified ruminal epithelial cells are in some respects similar to a 'non-differentiating keratinocyte' strain, derived from newborn foreskin epidermis. Cells in stratified colonies bound Ulex europaeus (UEAI) lectin which has been shown to be specific for differentiated epithelial cells in ruminal mucosa. Supplementation of culture medium with glucagon and insulin increased the total cell-overgrown area of collagen I cultures, whereas this effect was absent in cultures grown on collagen IV. In both cultures grown on collagen I or IV, hydrocortisone led to an increase in total cell-overgrown area, whereas Na-n-butyrate inhibited proliferation.

Animals↗
PubMed1995

Protection of goats against rinderpest by vaccination with attenuated peste des petits ruminants virus.

The ability of the attenuated peste des petits ruminants vaccine virus to protect small ruminants against virulent rinderpest virus was investigated. Out of four susceptible goats that were infected with the highly virulent Saudi strain of rinderpest virus by intranasal ioculation, three developed mild clinical signs of disease and infected susceptible in-contact goats and cattle with rinderpest virus. However, four goats which had been vaccinated with the attenuated peste des petits ruminants virus resisted challenge with virulent rinderpest virus and did not infect susceptible in-contact animals.

Animals↗
PubMed1995

In vitro survival of the BS isolate of Chlamydia psittaci (ovis) in ruminal and abomasal contents.

The ability of the pathogenic BS isolate of Chlamydia psittaci (ovis) to survive after inoculation into ruminal or abomasal contents, and chlamydial transport medium held at 39 degrees C, was assessed by taking hourly samples which were cultured in mitomycin-treated McCoy cells. The chlamydiae survived for nine hours in the ruminal contents, eight hours in the abomasal contents and for 12 hours in transport medium, when the experiment was concluded. There was a steady decrease in the numbers of the organism in the ruminal and abomasal contents as their pH decreased, but the numbers in the transport medium also decreased without a corresponding change in pH. It is therefore possible that ewes may become infected with C psittaci (ovis) orally via the gastrointestinal tract.

Abomasum↗
PubMedDate not supplied

The pathogenesis and immunology of bluetongue virus infection of ruminants.

Bluetongue (BLU) virus is transmitted from infected to susceptible ruminants by hematophagous vector midges (Culicoides species). Cattle are important reservoir hosts of the virus because infection typically is asymptomatic and characterized by prolonged cell associated viremia, and because at least some species of insect vector preferentially feed on cattle. Interaction of BLU virus with the cell membrane of erythrocytes in infected cattle likely facilitates both prolonged viremia as well as infection of the insect vector. BLU disease is most common in sheep and some wildlife species. A variety of host, agent and environmental factors clearly can influence expression of disease in these species. The pathogenesis of BLU virus infection of cattle and sheep is remarkably similar, thus the basis for expression of disease in sheep but not cattle remains to be firmly established. Some difference in susceptibility of endothelial cells to infection in the two species is one potential explanation. Ruminants develop a variety of antiviral responses after BLU virus infection. Antibodies to outer capsid protein VP2 are responsible for virus neutralization, and confer resistance to reinfection with the homologous serotype of BLU virus. Antibodies to epitopes on proteins which are common to all viruses of the BLU serogroup form the basis of current diagnostic serologic tests. Cell mediated responses have been incompletely characterized, in part because BLU virus replicates within dividing lymphocytes and virus-mediated cytolysis inhibits in vitro blastogenesis. Immunological competence of ruminants to BLU virus arises prior to midgestation, and suggestions that persistent immune tolerant BLU virus infection occurs after in utero exposure of cattle have not been substantiated and are not consistent with recent findings.

Animals↗
PubMed1989

Reticulo-ruminal motility in cattle (Bos indicus) and water buffaloes (Bubalus bubalis) fed a low quality roughage diet.

1. The effect of A and B sequence contractions of the reticulo-rumen on passage rate of digesta was compared in buffaloes and cattle fed low quality rhodes grass. 2. Both species ate the same amount per unit body weight but buffaloes spent 53% more time ruminating than cattle. 3. Buffaloes had fewer A and B sequence contractions each day and the rate of these contractions during eating, ruminating and at rest were slower. 4. A larger pool of fine feed particles in the rumen of buffaloes, generated by extra ruminating activity was associated with the 30% shorter mean residence time of particulate matter in the forestomach compared with cattle. 5. It is concluded that the difference in the number and frequency of contractions between the species was insufficient to affect passage rate of digesta from the stomach.

Animals↗
PubMed1989

Changes in the functions of the intestinal brush border membrane during the development of the ruminant habit in lambs.

1. Brush border membrane vesicles were prepared from lamb enterocytes. These were used to study the changes in the enzyme contents and the transport capacities which occur during the change from a milk to a roughage diet. 2. Na+-dependent transport of D-glucose was present in all regions of the small intestine of pre-ruminant lambs and absent in ruminants. 3. Na+-dependent transport of L-proline was present in all regions of the small intestine irrespective of the age of the animal. 4. Phosphate transport was seen only in the presence of a transmembrane pH gradient (acid outside). The transport was not stimulated by either Na+ or K+. The transport capacity increases 2-fold as the animal becomes ruminant. 5. The activities of lactase and maltase diminished with age. Alkaline phosphatase and aminopeptidase N activities remain constant. Sucrase activity cannot be detected in lambs of any age.

Alkaline Phosphatase↗
PubMed1991

Comparison of different media for the isolation of small ruminant strains of Mycobacterium paratuberculosis.

Two different egg based media, with and without the incorporation of sodium pyruvate, were used to isolate M. paratuberculosis from sheep, goat and cattle samples obtained at our laboratory for two years. Both media were adequate for bovine material, with a slightly improved isolation rate for Herrold's egg yolk medium incorporating sodium pyruvate; however, most of the small ruminant strains grew only on Löwenstein-Jensen medium without sodium pyruvate. Those results point out the need to use different media when working with small ruminant samples and provide further evidence for the existence of different varieties of M. paratuberculosis causing paratuberculosis in cattle and in small ruminants.

Animals↗
PubMed1992

A competitive ELISA using anti-N monoclonal antibodies for specific detection of rinderpest antibodies in cattle and small ruminants.

A competitive ELISA (C-ELISA) using monoclonal antibodies (mAbs) which bind to the nucleo-protein (NP) of rinderpest virus (RPV) for detection of RPV antibodies in cattle and small ruminant sera is described. Unlike virus neutralisation test (VNT), this test using mAb IVB2-4, can detect specific RPV antibodies without showing a cross-reaction with antibodies to peste-des-petits ruminants-virus (PPRV); by contrast, when mAb VE4-1 is used the test detects both RPV and PPRV antibodies, including low levels of antibodies that can be found in sera containing maternal antibodies. Although antibodies to the PPRV 75-1 strain are also detected with mAb 51-5-6, the test is suitable for assessing the immune status of cattle against the Rinderpest Old Kabete (RBOK) strain. The results from a panel of sera with a known status of vaccination provide evidence for a highly significant correlation between C-ELISA and VNT. This test may be a useful tool for a standardized and accurate determination of the immunity status of both cattle and small ruminants.

Animals↗
PubMed1995

Effects of exogenous somatotropin on whole-body glycemic response to insulin in young preruminant and ruminant lambs.

The purpose of this study was to determine the effects of exogenous recombinant bovine somatotropin (bST) treatment on whole-body glycemic responsiveness and sensitivity to exogenous insulin in preruminant and ruminant lambs. Twelve milk-fed (MF) and 12 ruminating (RUM) wether lambs weighing 20 +/- 0.6 kg were assigned to one of four treatment groups: MF control, MF plus bST, RUM control, and RUM plus bST. Lambs received a daily subcutaneous injection of 160 micrograms of sometribove (recombinant methionyl bST) bST/kg live weight or the equivalent volume of sterile water (control) for 10 d. The MF lambs had higher plasma insulin and nonessential fatty acids and lower acetate concentrations than RUM lambs (all P < 0.05). Plasma insulin-like growth factor concentrations were similar in both. The administration of bST raised plasma insulin-like growth factor-1 (P < 0.001) and insulin (P < 0.05) in MF and RUM lambs, but with greater effect in MF lambs (P < 0.01 and P < 0.1, respectively). Six successive dose-incremented insulin challenges (50, 100, 200, 300, 500, and 700 mU/kg body weight) were performed two per day on Days 8, 9, and 10 of treatment. Dose-response curves for absolute decline in glucose concentration from preinjection baseline to nadir were used to characterize whole-body responsiveness and sensitivity (ED50) to insulin. Somatotropin treatment increased insulin ED50 values 64 and 70% (P < 0.07) in RUM and MF lambs, respectively, suggesting that sensitivity to insulin was reduced. Insulin ED50 values were 40% higher in MF than in RUM lambs (P < 0.05). Insulin clearance rates increased with each dose increment to 300 mU/kg body weight (P = 0.001) and were 50% lower in bST-treated MF lambs than in all other treatment groups (P < 0.05). Results suggest that somatotropin modulates the insulin control of glucose homeostasis similarly in preruminant and ruminant lambs by decreasing sensitivity but not maximum responsiveness.

Aging↗