Physiology > Ruminant Physiology > Flashcards

Ruminant Physiology Flashcards

(52 cards)

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1
Q

Special features of ruminants

A
  • able to utilize forages other mammals cannot digest
  • forestomachs
  • esophageal and reticulo-omasal groove to bypass rumen
  • no upper incisors or canine teeth (dental pad)
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2
Q

Members of ruminant class

A
  • cattle
  • sheep
  • goats: low fiber, discriminant/browser
  • camelids (pseudoruminant)
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3
Q

Location of forestomach

A
  • rumen/reticulum is on the left side
  • omasum is in the middle
  • abomasum is on the right side
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4
Q

Advantages

A
  • break down cellulose to usable nutrients
  • allows synthesis of high biological value protein: low biological plant protein, non-protein nitrogen, nitrogenous end product (urea)
  • production of all B vitamins
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5
Q

Disadvantages

A
  • regular food intake at regular intervals
  • long hours chewing: food ingestion (4-7 hrs/day), chewing cud (8 hrs/day)
  • keep rumen fermentation vat balanced: large quantities of alkaline saliva, constant mixing, release of gas products
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6
Q

Rumen layers

A
  • gas
  • fiber mat/raft
  • fluid slurry (small particles)
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7
Q

Roughages

A

Cellulolytic

  • cellulose: glucose
  • hemicellulose: xylose
  • pectin: galactose
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8
Q

Legumes

A

Cellulolytic

- able to fix nitrogen (high protein)

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9
Q

Grains

A

Amylolytic

  • starches
  • simple sugars
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10
Q

Requirements for fermentation

A
  • regular addition of fresh food
  • presence of suitable microbes
  • steady removal of end products: gas, VFA, simple compounds, undigestible material
  • continuous mixing
  • propulsion of fine particles and fluid
  • anaerobic
  • stability: temperature, osmotic pressure, redox and pH
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11
Q

Protozoa

A
  • live in fiber mat
  • very sensitive to change
  • feed on bacteria, plant starch and PUFAs
  • provide high biological value protein
  • prefer pH of 6.2
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12
Q

10^10 bacteria/gram rumen content

A 
Cellulolytic bacteria
- pH of 6.2
Amylolytic bacteria
- pH of 5.8
Lactobacillus spp.
- takes over at pH <5.8
- lactic acid producing (creates rumen acidosis)
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13
Q

Rumen dysfunction

A
  • normal rumen pH 5.5-7.0
  • rapid feed changes
  • oral antibiotics
  • die off of normal rumen fauna
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14
Q

Rapid feed changes cause

A
  • acute acidosis/grain overload: pH < 5.0
  • subactue acidosis/SARA: pH < 5.5
  • takes 2 weeks for rumen fauna to adjust
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15
Q

Products of fermentation

A
  • gases: methane (CH4 and CO2) is eructated
  • volatile fatty acids: absorbed across rumen wall
  • microbial and protozoal protein and lipids: passed thru to abomasum
  • ammonia: absorbed across rumen wall
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16
Q

Volatile fatty acids

A
  • acetate: ketogenic
  • butyrate: ketogenic
  • propionate: glucogenic
  • ketone bodies: acetone, acetoacetate, betahydroxybutyrate
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17
Q

Is glucose available for absorption?

A

NO

  • blood glucose levels in ruminants is lower
  • insulin is lower
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18
Q

Acetic acid

A
  • minimal liver use
  • oxidized throughout most of the body to generate ATO
  • major source of acetyl CoA for synthesis of lipids
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19
Q

Proprionic acid

A
  • major liver use: removed from portal blood by liver
  • serves as a major substrate for gluconeogenesis
  • critical to the ruminant because almost no glucose reaches the small intestine for absorption
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20
Q

Butyric acid

A
  • comes out of the rumen as the ketone beta-hydroxybutyric acid
  • oxidized in many tissues for energy production
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21
Q

How long does it take to fast a ruminant

Study These Flashcards
A

24-48 hrs of no food, 12 hrs no water

22
Q

High fiber diets produce more _____

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A

Acetate and butyrate

- higher butterfat in milk

23
Q

High grain diets produce more ______

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A

Proprionate

- higher milk volume but lower butterfat

24
Q

Protein metabolism

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A

Broken down to simplest form (ammonia)

  • deamination of plant proteins
  • urea from diet and saliva
  • may feed up to 30% urea in diet (NPN)
  • utilization of urea requires adequate energy in form of VFA or starch
25
Gas production
Up to 40 L/hour 204 hours after a meal
26
Green house gases
- water vapor, carbon dioxide, methane, nitrous oxide, and ozone - carbon dioxide, CH4, and N2O - fossil fuel combustion, iron and steel prodution, cement manufacturing and municipal solid waste combustion
27
Methane makes up _____ of green house gases
7.9%
28
_______ has decreased, but milk production has increased 4 x per cow
Number of dairy cows | - working on feed additive to decrease methane
29
Rumen motility/rumination
- mixes rumen fermentation vat continuously - allows for regular release of gas (eructation) - allows for cud chewing: reduces particle size and increases saliva flow - filters fluid and particulate matter thru to omasum and abomasum
30
Innervation of forestomachs
``` Parasympathetic - vagus, CN 10 - promotes rumination, cud chewing Sympathetic - thoracic ganglia to celiac - decreases motility Nervous cows - drip/drool saliva - decrease (increase/hypermotile) rumen contractions ```
31
Types of rumen contractions
- primary: mixing and cud chewing - secondary: eructation - primary and secondary: cud chewing with eructation
32
Reticulum
- catches solid material - source of Hardware disease - prevention via magnet - other dietary indiscretions include: plastic bags, placenta, other
33
Omasum
- very fine particles - large surface area - absorption of VFAs, electrolytes and water - minor fermentation - regulates propulsion into abomasum - episodic slow contractions independent of reticular contractions
34
Abomasum
- true glandular stomach - pepsinogen and HCl secretion - average pH 3 - motility present but not well defined in fundic area - peristalsis of pyloric area at 6/minute
35
Differences in ruminants
- fasting for surgery | - blood glucose not as high (45-75 mg/dl)
36
Special features of calves
- are nonruminants at birth - reticulorumen is undeveloped - lack sucrase and secrete limited amylase - cannot digest plant proteins, unsaturated fats - dependent on milk sugars, glucose, milk protein and fat - liquid diets composed of milk, milk replacers, fermented colostrum - esophageal groove
37
Requirements for ruminal development
- establishment of bacteria in the rumen - liquid in the rumen (water) - outflow of material from the rumen (muscular action) - absorptive ability of the tissue - substrate
38
Development of rumination
- cud chewing has been observed at 7 days - by 2 months the calf can be weaned - by 4 to 6 months the rumen is fully functional - by 9 months the rumen is the same proportion of body weight as adult
39
Esophageal groove closure
Milk bypasses rumen - goes to abomasum - muscular groove seals rumen opening - stimulated by suckling - chemcially closed by sodium chloride solution, sugar solution, sodium bicarb
40
Ruminal drinkers
- failure of esophageal groove to close - over feeding - mismothering/starvation - putrefaction of rumen contents - treatment: modified feeding schedule, small amounts often, probiotics
41
Beginning rumination
- need fresh water to provide ample liquid for the rumen - bacteria needed to produce VFA (early bacteria are aerobic, similar to adults by 2 weeks) - substrate - volatile fatty acids (coarse material or high fiber placed in rumen have no effect on development) --> dilute solutions of VFA placed in rumen stimulate development - development of the rumen wall and papillae depend on grain intake
42
Important points
- calves need access to drinking water | - offer small amounts high quality calf starter daily (1 cup replaced daily if not eaten)
43
Salivary glands
``` Major - parotid (3rd cheek tooth): serous - mandibular: mixed - sublingual: mixed Minor - buccal, lingual, palatine: mucous Production: lysozyme, no amylase Volume: up to 200 L/day (100-150) ```
44
Composition of saliva
Isotonic to plasma - alkaline pH 8.1 - Na: 170 mEq/L - K: 13 mEq/L - HCO3: 48 mEq/L - Cl: 11 mEq/L - PO4 - nitrogen (77% as urea)
45
Functions of saliva
- moistens food/aids in deglutition - buffers acid production in rumen - provides nitrogen for microbial production of amino acids - protects against protein deficiency
46
Do ruminants produce saliva with atropine?
Yes, continuously
47
Clinical issues
- high grain diets decrease cud chewing and salivation (decreases buffering) - salivation issue with general anaesthesia - nervous animals: excessive drooling
48
Problems with swallowing
- choke - listeria: interferes with hypoglossal nerve - trauma/fractures of jaw - serious ECF, electrolyte and bicarb loss
49
Rumen
- fermentation | - absorption of VFAs, ammonia
50
Reticulum
- keeps large particles from entering omasum | - eructation and cud chewing
51
Omasum
- continues fermentation | - absorbs VFAs
52
Abomasum
- acid secreting for digestion | - true stomach
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