Rumen

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Robert C. Backus - One of the best experts on this subject based on the ideXlab platform.

  • The primary-secondary Rumen contraction and gas expulsion in sheep (Ovis aries).
    Comparative Biochemistry and Physiology Part A: Physiology, 2003
    Co-Authors: Laura E Peruzzo De Na Ville, Harry W Colvin, Robert C. Backus
    Abstract:

    Abstract 1. 1. Sheep Rumens were insufflated with nitrogen to 5, 10, 15 and 20cm HOH pressure and sustained at each pressure for 5 min. 2. 2. Measurements included Rumen motility, reticuloRumen myoelectrical activity, eructation frequency and volume, and changes in tracheal pressure. 3. 3. Associated with elevated intraRumen pressure was a previously unreported type of Rumen contraction on which gas expulsion occurred, the primary-secondary contraction. 4. 4. Gas expulsion volume was similar on primary-secondary and secondary contractions. 5. 5. The maximum Rumen contraction rate per min was 4–5 for secondaries and 1–2 for primary-secondaries. 6. 6. Irrespective of the sustained initial pressure, resting intraRumen pressure was reached within 5 min.

  • Elevated intra-Rumen pressure and secondary Rumen contractions in sheep (Ovis aries)
    Comparative Biochemistry and Physiology Part A: Physiology, 2003
    Co-Authors: Sandra A Mercer, Harry W Colvin, Robert C. Backus
    Abstract:

    Abstract 1. 1. Sheep Rumens were insufflated with nitrogen to 5, 10, 15, and 20cm water pressure and sustained at each pressure for 10 min. 2. 2. Measurements included Rumen motility, reticuloRumen myoelectric activity, eructation frequency and volume, changes in tracheal pressure and Rumen contraction amplitude. 3. 3. As intra-Rumen pressure increased, contractions designated as special secondary contractions appeared. 4. 4. At a pressure of approximately 15 cm water, most of the special secondary contractions became regular secondaries; therefore, the special secondaries were called pro-secondary contractions. 5. 5. Increased intra-Rumen pressure was associated with respiratory distress. The recovery phase following Rumen insufflation was accompanied by hyperpnea.

  • The effect of elevation of intraRumen pressure by nitrogen insufflation on eructation in cattle (Bos taurus).
    Comparative Biochemistry and Physiology Part A: Physiology, 1993
    Co-Authors: Robert C. Backus, Harry W Colvin, Edward J. Depeters
    Abstract:

    Abstract 1. 1. The in traRumen pressure (IRP) of eight calves was elevated for 10 min by nitrogen insufflation to pressures of 5, 10, 15 and 20 cm H2O. 2. 2. Rumen motility was evaluated by recording reticuloRumen myoelectrical activity and changes in luminal pressure, while eructation was determined from anterior tracheal and face mask gas expulsion. 3. 3. The elevation of IRP increased primary Rumen contraction frequency slightly and secondary Rumen contraction frequency as much as 3-fold. 4. 4. Rumen gas was expelled only during Rumen contractions and virtually always during secondary Rumen contractions. 5. 5. Cattle do not exhibit the primary-secondary contraction previously identified in sheep and their Rumen motility appears to be less sensitive than sheep to increases in IRP.

Harry W Colvin - One of the best experts on this subject based on the ideXlab platform.

  • The primary-secondary Rumen contraction and gas expulsion in sheep (Ovis aries).
    Comparative Biochemistry and Physiology Part A: Physiology, 2003
    Co-Authors: Laura E Peruzzo De Na Ville, Harry W Colvin, Robert C. Backus
    Abstract:

    Abstract 1. 1. Sheep Rumens were insufflated with nitrogen to 5, 10, 15 and 20cm HOH pressure and sustained at each pressure for 5 min. 2. 2. Measurements included Rumen motility, reticuloRumen myoelectrical activity, eructation frequency and volume, and changes in tracheal pressure. 3. 3. Associated with elevated intraRumen pressure was a previously unreported type of Rumen contraction on which gas expulsion occurred, the primary-secondary contraction. 4. 4. Gas expulsion volume was similar on primary-secondary and secondary contractions. 5. 5. The maximum Rumen contraction rate per min was 4–5 for secondaries and 1–2 for primary-secondaries. 6. 6. Irrespective of the sustained initial pressure, resting intraRumen pressure was reached within 5 min.

  • Elevated intra-Rumen pressure and secondary Rumen contractions in sheep (Ovis aries)
    Comparative Biochemistry and Physiology Part A: Physiology, 2003
    Co-Authors: Sandra A Mercer, Harry W Colvin, Robert C. Backus
    Abstract:

    Abstract 1. 1. Sheep Rumens were insufflated with nitrogen to 5, 10, 15, and 20cm water pressure and sustained at each pressure for 10 min. 2. 2. Measurements included Rumen motility, reticuloRumen myoelectric activity, eructation frequency and volume, changes in tracheal pressure and Rumen contraction amplitude. 3. 3. As intra-Rumen pressure increased, contractions designated as special secondary contractions appeared. 4. 4. At a pressure of approximately 15 cm water, most of the special secondary contractions became regular secondaries; therefore, the special secondaries were called pro-secondary contractions. 5. 5. Increased intra-Rumen pressure was associated with respiratory distress. The recovery phase following Rumen insufflation was accompanied by hyperpnea.

  • The effect of elevation of intraRumen pressure by nitrogen insufflation on eructation in cattle (Bos taurus).
    Comparative Biochemistry and Physiology Part A: Physiology, 1993
    Co-Authors: Robert C. Backus, Harry W Colvin, Edward J. Depeters
    Abstract:

    Abstract 1. 1. The in traRumen pressure (IRP) of eight calves was elevated for 10 min by nitrogen insufflation to pressures of 5, 10, 15 and 20 cm H2O. 2. 2. Rumen motility was evaluated by recording reticuloRumen myoelectrical activity and changes in luminal pressure, while eructation was determined from anterior tracheal and face mask gas expulsion. 3. 3. The elevation of IRP increased primary Rumen contraction frequency slightly and secondary Rumen contraction frequency as much as 3-fold. 4. 4. Rumen gas was expelled only during Rumen contractions and virtually always during secondary Rumen contractions. 5. 5. Cattle do not exhibit the primary-secondary contraction previously identified in sheep and their Rumen motility appears to be less sensitive than sheep to increases in IRP.

B W Mcbride - One of the best experts on this subject based on the ideXlab platform.

  • methanogens methane producers of the Rumen and mitigation strategies
    Archaea, 2010
    Co-Authors: Sarah E Hook, Andredenis G Wright, B W Mcbride
    Abstract:

    Methanogens are the only known microorganisms capable of methane production, making them of interest when investigating methane abatement strategies. A number of experiments have been conducted to study the methanogen population in the Rumen of cattle and sheep, as well as the relationship that methanogens have with other microorganisms. The Rumen methanogen species differ depending on diet and geographical location of the host, as does methanogenesis, which can be reduced by modifying dietary composition, or by supplementation of monensin, lipids, organic acids, or plant compounds within the diet. Other methane abatement strategies that have been investigated are defaunation and vaccines. These mitigation methods target the methanogen population of the Rumen directly or indirectly, resulting in varying degrees of efficacy. This paper describes the methanogens identified in the Rumens of cattle and sheep, as well as a number of methane mitigation strategies that have been effective in vivo.

  • long term monensin supplementation does not significantly affect the quantity or diversity of methanogens in the Rumen of the lactating dairy cow
    Applied and Environmental Microbiology, 2009
    Co-Authors: Sarah E Hook, Korinne S Northwood, Andredenis G Wright, B W Mcbride
    Abstract:

    A long-term monensin supplementation trial involving lactating dairy cattle was conducted to determine the effect of monensin on the quantity and diversity of Rumen methanogens in vivo. Fourteen cows were paired on the basis of days in milk and parity and allocated to one of two treatment groups, receiving (i) a control total mixed ration (TMR) or (ii) a TMR with 24 mg of monensin premix/kg of diet dry matter. Rumen fluid was obtained using an ororuminal probe on day −15 (baseline) and days 20, 90, and 180 following treatment. Throughout the 6-month experiment, the quantity of Rumen methanogens was not significantly affected by monensin supplementation, as measured by quantitative real-time PCR. The diversity of the Rumen methanogen population was investigated using denaturing gradient gel electrophoresis (DGGE) and 16S rRNA clone gene libraries. DGGE analysis at each sampling point indicated that the molecular diversity of Rumen methanogens from monensin-treated cattle was not significantly different from that of Rumen methanogens from control cattle. 16S rRNA gene libraries were constructed from samples obtained from the Rumen fluids of five cows, with a total of 166 clones examined. Eleven unique 16S rRNA sequences or phylotypes were identified, five of which have not been recognized previously. The majority of clones (98.2%) belonged to the genus Methanobrevibacter, with all libraries containing Methanobrevibacter strains M6 and SM9 and a novel phylotype, UG3322.2. Overall, long-term monensin supplementation was not found to significantly alter the quantity or diversity of methanogens in the Rumens of lactating dairy cattle in the present study.

  • Comparison of techniques for measurement of Rumen pH in lactating dairy cows
    J. Dairy Sci., 2004
    Co-Authors: Todd F. Duffield, A Fairfield, Peter Dick, Jeff Aramini, R Bagg, G Vessie, J Wilson, Jan C. Plaizier, B W Mcbride
    Abstract:

    Subacute Rumen acidosis is thought to be a common condition in early lactating dairy cattle; however, diagnosis is difficult. There are currently only two techniques available for measuring Rumen pH under field conditions: Rumenocentesis and oral stomach tube. Sixteen Rumen-fistulated cows were sampled in four sites of the Rumen (cranial-ventral, caudal-ventral, central, and cranial-dorsal) with a Rumen cannula. Rumen pH results were compared to those obtained at the same time with Rumenocentesis and with an oro-ruminal (Geishauser) probe. Rumen fluid was obtained between 6 and 12 wk of lactation. Samples were analyzed for pH, lactate, bicarbonate, sodium, potassium, and chloride. Rumen pH results were also compared to those obtained from 24-h continuous Rumen pH measurement using indwelling Rumen pH probes. Oro-ruminal probe samples had the highest pH values and the highest bicarbonate concentrations. Rumenocentesis samples had the lowest pH values and the lowest bicarbonate concentrations. Small differences in electrolyte concentrations were noted among Rumen fluid collection techniques in the different Rumen sites. The highest correlations of Rumen pH were obtained between Rumenocentesis and Rumen cannulation (cranial-ventral), and between Rumen cannulation (cranial-ventral) and the 24-h indwelling pH meter. Compared with samples obtained from the cranial-ventral Rumen, Rumenocentesis was more sensitive than the oro-ruminal probe in the measurement of low Rumen pH; both techniques were moderately specific. The most accurate field technique was Rumenocentesis. Improved field techniques are required for better on-farm diagnosis of subacute Rumen acidosis.

Laura E Peruzzo De Na Ville - One of the best experts on this subject based on the ideXlab platform.

  • The primary-secondary Rumen contraction and gas expulsion in sheep (Ovis aries).
    Comparative Biochemistry and Physiology Part A: Physiology, 2003
    Co-Authors: Laura E Peruzzo De Na Ville, Harry W Colvin, Robert C. Backus
    Abstract:

    Abstract 1. 1. Sheep Rumens were insufflated with nitrogen to 5, 10, 15 and 20cm HOH pressure and sustained at each pressure for 5 min. 2. 2. Measurements included Rumen motility, reticuloRumen myoelectrical activity, eructation frequency and volume, and changes in tracheal pressure. 3. 3. Associated with elevated intraRumen pressure was a previously unreported type of Rumen contraction on which gas expulsion occurred, the primary-secondary contraction. 4. 4. Gas expulsion volume was similar on primary-secondary and secondary contractions. 5. 5. The maximum Rumen contraction rate per min was 4–5 for secondaries and 1–2 for primary-secondaries. 6. 6. Irrespective of the sustained initial pressure, resting intraRumen pressure was reached within 5 min.

Sandra A Mercer - One of the best experts on this subject based on the ideXlab platform.

  • Elevated intra-Rumen pressure and secondary Rumen contractions in sheep (Ovis aries)
    Comparative Biochemistry and Physiology Part A: Physiology, 2003
    Co-Authors: Sandra A Mercer, Harry W Colvin, Robert C. Backus
    Abstract:

    Abstract 1. 1. Sheep Rumens were insufflated with nitrogen to 5, 10, 15, and 20cm water pressure and sustained at each pressure for 10 min. 2. 2. Measurements included Rumen motility, reticuloRumen myoelectric activity, eructation frequency and volume, changes in tracheal pressure and Rumen contraction amplitude. 3. 3. As intra-Rumen pressure increased, contractions designated as special secondary contractions appeared. 4. 4. At a pressure of approximately 15 cm water, most of the special secondary contractions became regular secondaries; therefore, the special secondaries were called pro-secondary contractions. 5. 5. Increased intra-Rumen pressure was associated with respiratory distress. The recovery phase following Rumen insufflation was accompanied by hyperpnea.