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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 l.jpg

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


Rumen contractions l.jpg
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


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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.


Types of ruminal contractions l.jpg
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



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  • 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


Incidence of pressure waves l.jpg
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


Neural control of reticuloruminal contractions l.jpg
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


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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


Need for eructation l.jpg

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


Mechanism of eructation l.jpg
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


Control of eructation l.jpg
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.


Bloat l.jpg
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


Feedlot bloat l.jpg
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


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  • 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


Pasture bloat l.jpg
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


Slide20 l.jpg

  • 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


Legume bloat prevention l.jpg
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


Slide22 l.jpg

  • 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


Rumination l.jpg
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


Particle size reduction l.jpg
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


Mechanism of rumination l.jpg
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


Control of rumination l.jpg
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


Rumination time l.jpg
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


Effects of diet on rumination l.jpg
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


Roughage value index l.jpg
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


Effects of rumination of the animal l.jpg
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


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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


Slide32 l.jpg

  • Energy cost Max. CWC intake/d

    • 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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