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Rumen Motility

Rumen Motility. Church: 67-106, 108-116, 468-474 Van Soest: 237-244 Ruckebusch and Thivend: 35-51; 103-119 Sjersen et al.: 155-164 Susenbeth et al. 1998. Energy Requirement for Eating in Cattle. J. Anim. Sci. 76:2701-2705. http://jas.fass.org/cgi/reprint/76/10/2701.pdf

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Rumen Motility

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  1. Rumen Motility Church: 67-106, 108-116, 468-474 Van Soest: 237-244 Ruckebusch and Thivend: 35-51; 103-119 Sjersen et al.: 155-164 Susenbeth et al. 1998. Energy Requirement for Eating in Cattle. J. Anim. Sci. 76:2701-2705. http://jas.fass.org/cgi/reprint/76/10/2701.pdf Mawuenyegah et al. 1997. Effect of Ammonia Treatment or Protein Supplementation on Rumination Behavior in Sheep Given Barley Straw. Animal Science 64(3):441-445. http://www.bsas.org.uk/Publications/Animal_Science_PDF_Back_Issues/Animal_Science_PDF_Back_Issues/ Cheng et al. 1998. A Review of Bloat in Feedlot Cattle. J. Anim. Sci. 76:299-308. http://jas.fass.org/cgi/reprint/76/1/299.pdf Majak et al. 1995. Pasture Management Strategies for Reducing the Risk of Legume Bloat in Cattle. J. Anim. Sci. 73:1493-1498. http://jas.fass.org/cgi/reprint/73/5/1493.pdf

  2. Rumen contractions • Functions • Inoculate incoming feed • Mix contents • Minimize effects of stratification • Move fermentation products to rumen wall • Particle sorting • Particle passage • Rumination • Eructation of fermentation gases • Location • Contractions are contractions of an entire sac of the reticulorumen, but are the result of muscular contraction primarily on the pillars

  3. Types of reticular contractions • Biphasic contraction • Action • Reticulum contracts to about ½ its size, relaxes, and contracts completely • Reticulo-omasal orifice is open during contraction, but closes when reticulum dilates • Assists in digesta passage from the reticulorumen • Passage more closely related to duration (r2 = .76) than amplitude (r2 = .56) or frequency (r2 = .15) • Duration • 7 to 12 seconds • Frequency • Eating – 35 to 45 seconds • Resting – 75 seconds • Triphasic contraction • Action • An extra complete contraction precedes a biphasic contraction of the reticulum • Contraction is associated with the movement of digesta up to the cardiac sphincter before rumination.

  4. Types of ruminal contractions • Primary contraction • Also called A-wave or backward moving • Action • A biphasic contraction of the reticulum • Anterior pillar contracts lifting the anterior sac. • Anterior fold rises to form barrier • Contraction moves across dorsal sac to dorsal blind sac from contraction of longitudinal pillar and dorsal coronary pillar • Dorsal blind sac contracts and dorsal sac relaxes from dorsal coronary pillar • Ventral sac contracts along longitudinal pillar • Ventral sac relaxed and Ventral blind sac contracts • Ventral contraction absent during rumination • Functions of the primary contraction • Mixing and inoculation of digesta • Particle sorting across the reticuloruminal and anterior folds • Duration of contraction • Fed animal – 30 to 50 seconds • Fasted animal – 12 to 18 seconds

  5. The primary contraction of the rumen

  6. Secondary contraction • Also called the B-wave or forward-moving contraction • Usually occurs after a primary contraction • Action • Contraction of the ventral blind sac continuing up through the dorsal blind sac using the dorsal coronary pillar • Contraction proceeds across dorsal sac forcing gas pocket to the cardiac sphincter • Function • Eructation • Duration • 30 seconds

  7. Incidence of pressure waves Contraction ActivityD DVDSVDVSV Feeding 1 27 5 56 Resting 10 35 25 22 Ruminating 22 28 37 6 Reticulum Cranial sac

  8. Neural control of reticuloruminal contractions • Nerves • Vagus nerve involved both in stimuli and inhibition • Sphlanchic nerve involved in inhibition • Stimuli for contractions • Stretch • Most common • Receptors • Low threshold receptors • Tension receptors • Stimulated by pressures greater than 4 mm Hg • Stimulate contractions • High threshold receptors • Epithelial receptors • Stimulated by pressures greater than 20 mm Hg • Inhibit contractions • Tactile stimulation • Near cardiac sphincter • Epithelial receptors • Stimulates triphasic contraction of reticulum • Low abomasal pH • Stimulates ruminal contractions • Hypoglycemia

  9. Inhibition of ruminal contractions • Abomasal distension • Hyperglycemia

  10. Factors affecting ruminal contractions • Feeding • Increases frequency and amplitude of contractions ActivityContractions/minAmplitudeP/S mm Hg Resting 1.2 18.2 - Feeding 2.0 22.1 1:1 Ruminating 1.1 10.4 - Fasting .3 Weak 5:1 • Diet • Feeding a finely ground forage • Reduced rate of contractions • Reduced amplitude of contractions • Requires 2-6 weeks to adapt • Volatile fatty acids • Acetic, propionic, and butyric acids at 90, 50, and 37 mM given separately or at 33.5, 29.3, and 21.1 mM given as a mixture will inhibit primary contraction • Metabolic problems • Hardware disease, hypocalcemia, or hyperglycemia will inhibit ruminal contractions

  11. Gas production Peak Occurs 30 min to 2 hr post-feeding 12-27 l/min Average 1-2 l/min Approximately ¼ to 1/3 of CO2 produced in rumen is absorbed into blood and removed through the lungs Only 1/5 of the CH4 is removed through the lungs Composition of rumen gas __Gas__ _%__ CO2 65.35 CH4 (variable) 27.76 N2 7.00 O2 (at wall) .56 H2 .18 H2S .01 Need for eructation

  12. Mechanism of eructation • Biphasic contraction of reticulum • Modified primary contraction of rumen • Secondary contraction of rumen • Ruminal gas pocket forced forward • Anterior fold and reticuloruminal fold rise to hold digesta away from cardiac sphincter • Cardiac sphincter relaxes allowing esophagus to fill with gas • Rapid reverse peristallsis of the esophagus • Diaphragmatic and Pharyngeal sphincters open • Nasopharyngeal sphincter closes • Epiglottis opens while thoracic muscles contract • Cause 80% of gas to enter trachea • Acts as a muffler • Animal exhales

  13. Control of eructation • Stimulus • Gaseous distension of the reticulum and rumen • Inhibition • Presence of digesta near the cardiac sphincter • Affects all three sphincters • Prevents digesta from entering lungs • Epinephrine • Histamine • Inhibition of eructation will cause the animals to bloat • Ruminal pressures will increase to 45 to 100 mm Hg.

  14. Bloat • Types of bloat • Free gas bloat • Gas pocket over the digesta is normal, but can’t be eructated because of a physical obstruction in the esophagus or anatomical abnormality • Frothy bloat • Gases form a foam over the digesta that inhibits eructation when it touches the reticular wall near the cardiac spincter • Two types • Feedlot bloat • Pasture or legume bloat

  15. Feedlot bloat • Etiology • Occurs in ruminant animals fed high grain diets particularly during adaptation to the diets • Causes • Digesta becomes viscous and gel-like that trap gas as a foam • Viscosity increased by • The presence of bacterial capsules on some gram + starch-digesting bacteria such as Streptococcus bovis and lactobacilli • Streptococcus bovis and lactobacilli only found in large numbers in animals not adapted to high grain diets • The presence of short-chain starches (dextrans) • Increased concentrations of VFAs • Reduce ruminal motility • Increased intake of a dense diet • Lowers cardiac sphincter • Increased numbers of mucinolytic bacteria • Mucin will prevent foam • Reduced outflow rate

  16. Prevention • Slowly adapt animals to high grain diets • Feed adequate fiber • Use less fermentable grains • Wheat or barley > Corn or sorghum • Steam-flaked > Coarse ground • Feed ionophores (Monensin or Salinomycin) • Decreased growth of Streptococcus bovis and lactobacilli • Decreased feed intake • Decreased methane production

  17. Pasture bloat • Occurs in ruminant animal consuming fresh legumes such as alfalfa, white clover and red clover or the small grain wheat when immature or immediately after a frost • Causes • Presence of high concentrations of soluble protein present in chloroplasts increases surface tension causing foam • Earlier research implied that a protein named ribulose-1,5-biphosphate carboxylase oxygenase (also called the 18S protein) • 3 – 6% of DM in bloat-causing legumes • Recent research shows that total soluble protein concentration is more highly related to bloat • Rapid cell wall digestion • Rapid release of chloroplasts • Rapid release of cell wall fragments that get trapped in foam • Pectin • A cell wall component in high concentration in legume cell walls • Pectin metabolism • Pectin fermented to Pectic acid (binds 2000x its weight in water increasing viscosity) • Pectic acid rapidly fermented to methane

  18. Minerals • K, Ca, Ni, Zn, and Mg stabilize foam • Frosted legumes • K is released into cytoplasm • Decreased Na:K ratio results in increased binding between proteins • Increases surface tension causing bloat • Decreased chewing • Decreased salivary mucin and Na • Mucin prevents foaming • Reduced ruminal outflow Retention time of CoEDTA, hr Nonsusceptible 8 Susceptible 12-17 • Increases concentrations of chloroplasts and chlorophyll • Saponin • Surfactant glucoside • Minor role in stabilizing foam • pH less than 6 • Stabilizes foam • Toxic factors • Amines like histamine reduce motility

  19. Legume bloat prevention • Mix grasses with legumes in pastures • Allow legumes to mature before grazing • Use of non-bloating legume species • Birdsfoot trefoil, sanfoin, crownvetch, berseem clover, and some cultivars of red clover • Produce high concentrations of tannins • Polymers of phenolic compounds • Actions • Binds proteins preventing release • Reduce rate of digestion • Feed some dry hay before putting animals on pastures • Move to new paddocks after early morning • Not related to dew • Appears related to selective retention of chloroplasts • Increase grazing pressure • Forces animals to increase consumption of stems to leaves • Close availability of water

  20. Use of surfactants • Vegetable oil • Poloxalene (Bloatguard) • Effective at 10 gm/1000 lb/day • May be used as drench, block or loose supplement • Questionable palatability • Antibiotics • Penicillin and tylosin • Prevents bloat for a short period • Bacteria adapt causing bloat • Ionophores • Decreased incidence by 50%, but didn’t prevent it • Genetic selection • After 10 years, bloat removed from herd • Phenotype difference • Increased rumen liquid volume

  21. Rumination • Functions • Rechewing to increase particle size • Saliva flow • Particle breakdown • Chewing during eating • Functions • Preparation for swallowing • Release soluble constituents • Damage plant tissues for microbial attachment • Chewing during rumination • Functions • Decrease particle size for passage • Damage plant tissues for microbial attachment • Microbial digestion • Reticuloruminal contractions

  22. Particle size reduction Alfalfa Meadow RyegrassRed cloverAlfalfahayhay ( % of intake) DM digested in RR 59.9 61.7 55.3 37.1 49.3 Soluble DM released 36.8 37.6 31.9 22.9 20.4 by chewing during eating Large particles reduced to < 1 mm by: Eating 11.8 14.0 14.5 14.3 14.4 Ruminating 12.0 13.7 16.4 26.6 38.5 (% of particle reduction) Particle reduction by 50.4 49.4 53.1 65.0 72.8 rumination

  23. Mechanism of rumination • Triphasic contraction of the reticulum • Forces digesta to cardia • Animal inhales with epiglottis closed • Produces a vacuum of 60 to 80 mm water in esophagus • Cardia opens and esophagus dilates • Negative pressure sucks digesta into esophagus • Rapid reverse peristalsis moves digesta to mouth • Bolus is rechewed • Chewing is slower and more deliberate than during eating • Digesta reinsalivated • Saliva composition is different than during eating • Parotid glands secrete more saliva during rumination than eating • Saliva from parotid glands secrete more HCO3- than other glands • Reswallowing • After reswallowing, the rumen undergoes a primary contraction to move it back in the rumen • 20 to 65% of the DM is released in a fine state and will not return to the mouth again

  24. Control of rumination • Controlled by tactile receptors (epithelial receptors) near the cardiac sphincter, reticuloruminal fold and anterior sac • Stimulated by scratching of feed against the rumen wall • Reflex is semiautomatic • Can be stopped anytime • EEG resembles sleeping

  25. Rumination time • Average times for a grazing animal • Eating – 8 hours • Ruminating – 8 hours • Resting – 8 hours • Ruminating time is quite variable • Factors affecting rumination time • Fiber content of diet • Physical form of diet

  26. Effects of diet on rumination • Increasing the proportion of grain in the diet will decrease rumination Chews/day Hay 50,100 Dried grass 36,100 Concentrate 11,000 • Increasing the maturity of the forage in a diet will increase rumination • Decreasing the particle size of the diet will decrease the rumination time • Increasing feed intake will reduce the rumination time per gm of feed consumed • Cattle ruminate less per kg NDF than sheep or goats

  27. Roughage value index Total chewing, min/kg DM Alfalfa hay, Chopped 44.3 Long 61.5 Pelleted 36.9 Oat straw 160 Cottonseed hulls 30.1 Alfalfa silage Fine chop 22.3 Medium chop 26.0 Corn-ground 5.1 Soybean meal 6.0 Minerals 0 Molasses 0 Urea 0

  28. Effects of rumination of the animal • Saliva flow • More saliva secreted during rumination than eating • Affects • Rumen pH • Fiber digestion • Microbial growth • VFA and methane production • Maintenance of intake • Structure of rumen epithelium • Prevention of liver abscess and laminitis • Liquid rate of passage • Efficiency of microbial growth within the rumen • DM intake • Ruminating time is a limiting factor controlling intake of high fiber diets Maximum time, hours Ruminating 10-11 Grazing 13 • Lower rumination efficiency (min/g CWC) limits intake of smaller and growing animals

  29. Body weight Rumination Max. CWC intake/d Animalkgkg.75min/g CWCg/kg BWg/kg.75 BW Lambs 40 16.0 2.05 5.8 14.6 Goats 39 15.6 1.30 9.4 23.7 Mature sheep 82 27.3 1.18 4.9 14.9 Calves 119 35.9 .78 5.2 17.2 Heifers 1 213 55.7 .42 5.4 20.8 Heifers 2 342 79.6 .19 7.4 31.8 Heifers 3 456 98.6 .16 6.5 29.9 Mature cows 561 115.0 .10 8.2 40.1

  30. Energy cost • Total chewing • increases maintenance cost by .24 kcal/hr/kg BW and accounts for 30% of maintenance requirement • Accounts for difference in maintenance energy requirements of cattle fed high grain or high forage diets. • Contribution of rumination to energy cost of total chewing varies Time, min/kg DM consumed FeedstuffEatingRuminating Oat straw 41-58 94-133 Medium quality hay 20-40 63-87 Good quality hay 27-31 55-74 Concentrates, pelleted 4-10 0-25 Finely ground oat straw 11-24 0-20 Finely ground hay 13 0-6

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