Rumen fermentation is the largest commercial fermentation process. It occurs in the rumens of ruminant animals like cows and goats. The rumen contains billions of microbes that break down plant fibers in feed into volatile fatty acids and microbial protein. This symbiotic relationship provides nutrients to both the microbes and the ruminant animal. Key features of rumen fermentation include attachment of microbes to feed particles, the four steps of rumination, and roles of different microbial populations like bacteria and protozoa.
Carbohydrate digestion and metabolism in Ruminants Carbohydrate Digestion...Dr. Rahul kumar Dangi
The rumen of such animals will have higher amylolytic bacteria than cellulolytic bacteria present in the rumen of roughage- and pasture-fed animals.
Factors such as the forage:concentrate ratio, the physical form of the diet (ground vs. pelleted), feed additives, and animal species can affect the rumen fermentation process and VFA production.
Molar ratios of VFAs are dependent on the forage:concentrate ratio of the diet. Cellulolytic bacteria tend to produce more acetate, while amylolytic bacteria produce more propionic acid.
Typically three major VFA molar ratios are 65:25:10 with a roughage diet and 50:40:10 with a concentrate-rich diet.
Changes in VFA concentration can lead to several disorders of carbohydrate digestion in ruminants.
Rumen acidosis occurs when animals are fed high-grain-rich diets or when animals are suddenly changed from pasture- or range-fed to feedlot conditions
Very little digestion occurs in the mouth in farm animals.
The small intestine is the site of carbohydrate digestion in monogastrics.
Pancreatic amylase acts on alpha 1,4 links, and other disaccharidases and remove disaccharide units.
The end product (mainly glucose) diffuses into the brush-border using ATP-dependent glucose transporters.
Undigested (fiber, nonstarch polysaccharides [NSP]) in the hindgut can serve as an energy source for hindgut microbes in monogastrics.
Ruminant carbohydrate digestion is very different from monogastrics. First, there is no amylase secreted in the saliva and then most carbs are fermented in the rumen by microbial enzymes.
Carbohydrates are fermented to volatile fatty acids (VFAs) in the rumen. These include acetic acid, propionic acid, and butyric acid.
VFAs are absorbed through the rumen wall into the portal vein and are carried to the liver.
Ratios of the VFAs change with the type of diet. Roughage diets favor microbes that produce more acetic acid, whereas concentrate diets favor microbes that produce more propionic acid.
Carbohydrate fermentation disorders in ruminants include rumen acidosis (grain overload), when cattle are fed high-starch-based cereal or grain-rich diets or when there is a sudden change from pasture to feedlot FIBROUS CARBOHYDRATES
Cellulose and hemicellulose bound with lignin in plant cell walls or fiber. Provide bulk in the rumen. Fermented slowly.
The lignin content of fiber increases with plant maturity and the extent of cellulose and hemicellulose fermentation in the rumen decreases.
Fiber in the form of long particles essential to stimulate rumination. Which enhances the breakdown and fermentation of fiber and stimulates ruminal contraction, and increases the flow of saliva to the rumen.
Saliva contains sodium bicarbonate (baking soda) and phosphate salts which help to maintain pH of the rumen close to neutral.
Rations lacking fiber generally result in a low percentage of fat in the milk and contribute to digestive disturbances (e.g., displaced abomasum, rumen acidosis).
Non-fibrous carbohydrat
Carbohydrate digestion and metabolism in Ruminants Carbohydrate Digestion...Dr. Rahul kumar Dangi
The rumen of such animals will have higher amylolytic bacteria than cellulolytic bacteria present in the rumen of roughage- and pasture-fed animals.
Factors such as the forage:concentrate ratio, the physical form of the diet (ground vs. pelleted), feed additives, and animal species can affect the rumen fermentation process and VFA production.
Molar ratios of VFAs are dependent on the forage:concentrate ratio of the diet. Cellulolytic bacteria tend to produce more acetate, while amylolytic bacteria produce more propionic acid.
Typically three major VFA molar ratios are 65:25:10 with a roughage diet and 50:40:10 with a concentrate-rich diet.
Changes in VFA concentration can lead to several disorders of carbohydrate digestion in ruminants.
Rumen acidosis occurs when animals are fed high-grain-rich diets or when animals are suddenly changed from pasture- or range-fed to feedlot conditions
Very little digestion occurs in the mouth in farm animals.
The small intestine is the site of carbohydrate digestion in monogastrics.
Pancreatic amylase acts on alpha 1,4 links, and other disaccharidases and remove disaccharide units.
The end product (mainly glucose) diffuses into the brush-border using ATP-dependent glucose transporters.
Undigested (fiber, nonstarch polysaccharides [NSP]) in the hindgut can serve as an energy source for hindgut microbes in monogastrics.
Ruminant carbohydrate digestion is very different from monogastrics. First, there is no amylase secreted in the saliva and then most carbs are fermented in the rumen by microbial enzymes.
Carbohydrates are fermented to volatile fatty acids (VFAs) in the rumen. These include acetic acid, propionic acid, and butyric acid.
VFAs are absorbed through the rumen wall into the portal vein and are carried to the liver.
Ratios of the VFAs change with the type of diet. Roughage diets favor microbes that produce more acetic acid, whereas concentrate diets favor microbes that produce more propionic acid.
Carbohydrate fermentation disorders in ruminants include rumen acidosis (grain overload), when cattle are fed high-starch-based cereal or grain-rich diets or when there is a sudden change from pasture to feedlot FIBROUS CARBOHYDRATES
Cellulose and hemicellulose bound with lignin in plant cell walls or fiber. Provide bulk in the rumen. Fermented slowly.
The lignin content of fiber increases with plant maturity and the extent of cellulose and hemicellulose fermentation in the rumen decreases.
Fiber in the form of long particles essential to stimulate rumination. Which enhances the breakdown and fermentation of fiber and stimulates ruminal contraction, and increases the flow of saliva to the rumen.
Saliva contains sodium bicarbonate (baking soda) and phosphate salts which help to maintain pH of the rumen close to neutral.
Rations lacking fiber generally result in a low percentage of fat in the milk and contribute to digestive disturbances (e.g., displaced abomasum, rumen acidosis).
Non-fibrous carbohydrat
Formulating Diets for Groups of Lactating CowsDAIReXNET
Dr. Bill Weiss of The Ohio State University presented this material for DAIReXNET on February 26, 2015. For the full presentation, please visit our archives at http://www.extension.org/pages/15830/archived-dairy-cattle-webinars
Manipulations of rumen function that can augment livestock productivity are;
Correction of concentrate to roughage ratio
Feed bypass or escaped nutrients
Defaunation of rumen
Use of yeast as probiotics
Use of anaerobic fungi
Use of other feed additives
This slides contains information on precision feeding in dairy cattle and requirement of energy, protein, fat, minerals and vitamins of a dairy cattle during lactation. Precision feeding protects reproductive health and milk production while reducing the nutrient loss in manure.
Only 25-35% of the N in feed goes into milk, with the rest excreted in feces and urine.
Dairy diets often have 120-160% of the P and that the excess is excreted in the manure.
Cost of feed can be reduced.
Precision feeding helps to improve water quality
Improving the efficiency of use of feed N.
Reduce SARA condition.
Controlled-release urea in dairy cattle feed.
Straw treatment-Ammoniation.
Reducing Enteric Methane Losses from Ruminant Livestock.
Phase feeding in dairy cattle.
Feeding bypass fat in early lactation.
Use of chelated minerals in dairy animals.
Nutraceuticals in dairy animal precision feeding.
10. Use of area specific mineral mixture to precise dairy animal nutrition.
11. TMR in precision nutrition.
12. Manipulation of dietary CAD.
Five distinct feeding phases can be defined to attain optimum production, reproduction and health of dairy cows:
Early lactation—0 to 70 days (peak milk production) after calving (postpartum).
Peak DM intake—70 to 140 days (declining milk production) postpartum.
Mid and late lactation—140 to 305 days (declining milk production) postpartum.
Dry period—60 days before the next lactation.
Transition or close-up period—14 days before to parturition.
Feed top quality forage.
Make sure the diet contains adequate amounts of CP, DIP and UIP.
Increase grain intake at a constant rate after calving.
Consider adding fat (0.4-0.6 kg/cow/day) to diets.
Allow constant access to feed.
Minimize stress conditions.
Limit urea to 80-160g/day.
Buffers, such as Na bicarbonate alone or in combination with Mg oxide (rumen pH)
In Transition period
Increase grain feeding, so cows are consuming 4.5-6 kg grain/day at calving (1% of B.wt)
Increase protein in the ration to between 14 - 15 % of the ration DM
Limit fat in the ration to 0.1kg. High fat feeding will depress DM intake.
Maintain 2.5-4kg of long hay in the ration to stimulate rumination.
Feed a low-Ca ration (< 0.20%, reduce Ca intake to 14 to 18 g/d)
Also, feed a diet with a negative dietary electrolyte balance (-10 to -15meq/100 g DM) may alleviate milk fever problems
Niacin (to control ketosis) and/or anionic salts (to help prevent milk fever) should be included in the ration during this period.
Far Off To Fresh Cow- Opportunities to Improve Transition PerformanceDAIReXNET
Dr. mike Overton presented this information for DAIReXENT on Monday, March 18, 2013. For more information, please see our archived webinars page at www.extension.org/pages/15830/archived-dairy-cattle-webinars.
Formulating Diets for Groups of Lactating CowsDAIReXNET
Dr. Bill Weiss of The Ohio State University presented this material for DAIReXNET on February 26, 2015. For the full presentation, please visit our archives at http://www.extension.org/pages/15830/archived-dairy-cattle-webinars
Manipulations of rumen function that can augment livestock productivity are;
Correction of concentrate to roughage ratio
Feed bypass or escaped nutrients
Defaunation of rumen
Use of yeast as probiotics
Use of anaerobic fungi
Use of other feed additives
This slides contains information on precision feeding in dairy cattle and requirement of energy, protein, fat, minerals and vitamins of a dairy cattle during lactation. Precision feeding protects reproductive health and milk production while reducing the nutrient loss in manure.
Only 25-35% of the N in feed goes into milk, with the rest excreted in feces and urine.
Dairy diets often have 120-160% of the P and that the excess is excreted in the manure.
Cost of feed can be reduced.
Precision feeding helps to improve water quality
Improving the efficiency of use of feed N.
Reduce SARA condition.
Controlled-release urea in dairy cattle feed.
Straw treatment-Ammoniation.
Reducing Enteric Methane Losses from Ruminant Livestock.
Phase feeding in dairy cattle.
Feeding bypass fat in early lactation.
Use of chelated minerals in dairy animals.
Nutraceuticals in dairy animal precision feeding.
10. Use of area specific mineral mixture to precise dairy animal nutrition.
11. TMR in precision nutrition.
12. Manipulation of dietary CAD.
Five distinct feeding phases can be defined to attain optimum production, reproduction and health of dairy cows:
Early lactation—0 to 70 days (peak milk production) after calving (postpartum).
Peak DM intake—70 to 140 days (declining milk production) postpartum.
Mid and late lactation—140 to 305 days (declining milk production) postpartum.
Dry period—60 days before the next lactation.
Transition or close-up period—14 days before to parturition.
Feed top quality forage.
Make sure the diet contains adequate amounts of CP, DIP and UIP.
Increase grain intake at a constant rate after calving.
Consider adding fat (0.4-0.6 kg/cow/day) to diets.
Allow constant access to feed.
Minimize stress conditions.
Limit urea to 80-160g/day.
Buffers, such as Na bicarbonate alone or in combination with Mg oxide (rumen pH)
In Transition period
Increase grain feeding, so cows are consuming 4.5-6 kg grain/day at calving (1% of B.wt)
Increase protein in the ration to between 14 - 15 % of the ration DM
Limit fat in the ration to 0.1kg. High fat feeding will depress DM intake.
Maintain 2.5-4kg of long hay in the ration to stimulate rumination.
Feed a low-Ca ration (< 0.20%, reduce Ca intake to 14 to 18 g/d)
Also, feed a diet with a negative dietary electrolyte balance (-10 to -15meq/100 g DM) may alleviate milk fever problems
Niacin (to control ketosis) and/or anionic salts (to help prevent milk fever) should be included in the ration during this period.
Far Off To Fresh Cow- Opportunities to Improve Transition PerformanceDAIReXNET
Dr. mike Overton presented this information for DAIReXENT on Monday, March 18, 2013. For more information, please see our archived webinars page at www.extension.org/pages/15830/archived-dairy-cattle-webinars.
Manipulation of rumen function to augment livestock productivityUCV&AS IUB
Manipulations of rumen function that can augment livestock productivity are;
Correction of concentrate to roughage ratio
Feed bypass or escaped nutrients
Defaunation of rumen
Use of yeast as probiotics
Use of anaerobic fungi
Use of other feed additives
rumen, microbes of the rumen, bacteria of the rumen, process in ruminant animals, gut of ruminant animals, bacterial concentrations in ruminant animals, bacterial fluctuations in ruminant animals
Embracing GenAI - A Strategic ImperativePeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
Acetabularia Information For Class 9 .docxvaibhavrinwa19
Acetabularia acetabulum is a single-celled green alga that in its vegetative state is morphologically differentiated into a basal rhizoid and an axially elongated stalk, which bears whorls of branching hairs. The single diploid nucleus resides in the rhizoid.
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
Biological screening of herbal drugs: Introduction and Need for
Phyto-Pharmacological Screening, New Strategies for evaluating
Natural Products, In vitro evaluation techniques for Antioxidants, Antimicrobial and Anticancer drugs. In vivo evaluation techniques
for Anti-inflammatory, Antiulcer, Anticancer, Wound healing, Antidiabetic, Hepatoprotective, Cardio protective, Diuretics and
Antifertility, Toxicity studies as per OECD guidelines
Synthetic Fiber Construction in lab .pptxPavel ( NSTU)
Synthetic fiber production is a fascinating and complex field that blends chemistry, engineering, and environmental science. By understanding these aspects, students can gain a comprehensive view of synthetic fiber production, its impact on society and the environment, and the potential for future innovations. Synthetic fibers play a crucial role in modern society, impacting various aspects of daily life, industry, and the environment. ynthetic fibers are integral to modern life, offering a range of benefits from cost-effectiveness and versatility to innovative applications and performance characteristics. While they pose environmental challenges, ongoing research and development aim to create more sustainable and eco-friendly alternatives. Understanding the importance of synthetic fibers helps in appreciating their role in the economy, industry, and daily life, while also emphasizing the need for sustainable practices and innovation.
Macroeconomics- Movie Location
This will be used as part of your Personal Professional Portfolio once graded.
Objective:
Prepare a presentation or a paper using research, basic comparative analysis, data organization and application of economic information. You will make an informed assessment of an economic climate outside of the United States to accomplish an entertainment industry objective.
Introduction to AI for Nonprofits with Tapp NetworkTechSoup
Dive into the world of AI! Experts Jon Hill and Tareq Monaur will guide you through AI's role in enhancing nonprofit websites and basic marketing strategies, making it easy to understand and apply.
Safalta Digital marketing institute in Noida, provide complete applications that encompass a huge range of virtual advertising and marketing additives, which includes search engine optimization, virtual communication advertising, pay-per-click on marketing, content material advertising, internet analytics, and greater. These university courses are designed for students who possess a comprehensive understanding of virtual marketing strategies and attributes.Safalta Digital Marketing Institute in Noida is a first choice for young individuals or students who are looking to start their careers in the field of digital advertising. The institute gives specialized courses designed and certification.
for beginners, providing thorough training in areas such as SEO, digital communication marketing, and PPC training in Noida. After finishing the program, students receive the certifications recognised by top different universitie, setting a strong foundation for a successful career in digital marketing.
2. Rumen Fermentation
World’s largest
commercial
fermentation space
100 billion liters or
rumen volume in
domestic animals
1010 to 1012 cells/mL
Rumen capacity ranges
from less than 1 liter (1
quart) in a duiker to 200
liters (50 gallons) in a
cow
3. Ruminants
Continuous culture fermenters
Input and output
Lignocellulosic substrates (forages)
digested
Cellulase complex
Hemicellulases
Nitrogen capture (NPN)
8 x 1015 mouths to feed
Because of these microbial enzymes, ruminants can utilize feedstuffs
that provide little to no nutritional benefit to non-ruminants
4. Four Steps of Rumination
Regurgitation
Reverse peristalsis carries food to mouth
Remastication
Liquid squeezed from bolus and
swallowed
Bolus chewed
Reinsalivation
Adding more saliva
Redeglutition
Swallowing bolus and liquids
5. Rumination
Allows animal to forage and eat food rapidly,
and then store for later digestion
Reduces particle size
Only small particles leave reticulorumen
Increases surface area for microbial
attachment and digestion/fermentation
Breaks down impervious plant walls
Further stimulation of saliva flow (saliva serves
to buffer rumen)
6. Rumination Time
Average times for a grazing animal
Eating – 8 hours
Ruminating – 8 hours
Resting – 8 hours
Ruminating time is quite variable (high
variation)
Reducing forage:concentrate decreases rumination
Reducing particle size of forage decreases time
spent ruminating
7. Mechanism of Rumination: Regurgitation
Stimulus – digesta in fiber mat scratching surface
near cardiac sphincter
Contraction of the reticulum forces digesta to cardia
Animal inhales with epiglottis closed to produce a
vacuum
Cardia sphincter opens and esophagus dilates
Negative pressure (vacuum) sucks digesta into esophagus
Rapid reverse peristalsis moves digesta to mouth
8. Mechanism of Rumination: Remastication,
Reinsalivation, and Redeglutition
Bolus is rechewed
Chewing is slower and more deliberate than during
initial eating phase
Digesta reinsalivated
Parotid glands secrete more saliva during rumination
than eating
Saliva from parotid glands secrete more NaHCO3- than
other glands
Reswallowing
After reswallowing, the rumen contracts to move
swallowed bolus into the rumen
10. Reducing Particle Size of
Ingested Feeds
Chewing during eating (minimal)
Preparation for swallowing
Release soluble constituents
Damage plant tissues for microbial attachment
Chewing during remastication (extensive)
Decrease particle size for passage
Damage plant tissues for microbial attachment
Microbial digestion
Reticuloruminal contractions
11. Rumen Contractions
Inoculate incoming feed with microbes
Mix contents
Minimize effects of stratification
Move fermentation products (VFA’s) to
rumen wall
Particle sorting and passage of small
particles to omasum
Rumination
Eructation of fermentation gases
12. Need for Eructation
Peak gas production Composition of rumen
occurs 30 min to 2 hr post- gas
feeding (12-27 liters/min)
Average is 1-2 liters/min
Approximately 30% of CO2 __Gas__ _%__
produced in rumen is CO2 65.35
absorbed into blood and CH4 (variable) 27.76
removed through the lungs N2 7.00
Remainder is eructated
O2 (at wall) .56
Only 20% of the CH4 is
removed through the lungs H2 .18
80% eructated H2S .01
13. Control of Eructation
Stimulus
Gaseous distension of the reticulum and rumen
Esophagus dilates & animal belches
12-30 L per minute for cattle
3-17 times per minute
Inhibition
Presence of digesta near the cardiac sphincter
Affects all three sphincters
Protective mechanism to prevent digesta from entering lungs
Epinephrine – fight or flight response
Inhibition of eructation will cause the animals to bloat
Ruminal pressures will increase up to 100 mm Hg
Stable froth or foam formed in rumen
14. Feed the Microbes, Let the Microbes Feed the Ruminant!
Feed In
VFA
Microbial Protein
Vitamins
The nutrients presented to the
animal after ruminal fermentation
are very different than those entering
the rumen as feed
15. Rumen Digestion and Fermentation
CO2
VFA
Degradable Rumen Microbial cells
Feed microbes NH3
CH4
Heat
Long-chain
fatty acids
H2S
Products in red are used by the host animal
Products listed in black and green are not useable by the animal
Products listed in green are the primary energy losses from the rumen
17. Rumen Microorganisms
Nutritional Requirements
CO2
Energy
End products from digestion of structural carbohydrates
Fermentation of sugars
Nitrogen
Ammonia (majority of nitrogen needs)
Amino acids (cellulolytic bacteria)
Minerals
Co, S, P, Na, K, Ca, Mg, Mn, Fe, Zn, Mo, Se
Vitamins
None required in mixed cultures of bacteria
18. Symbiotic Relationship
Microbes provide to the ruminant
Digestion of cellulose and hemicellulose
Provision of high quality protein
Production of VFA
Provision of B vitamins
Detoxification of toxic compounds
19. Digestion of Cellulose and
Hemicellulose
Cellulases are all of microbial origin
Without microbes, ruminants would not be
able to use forage crops such as pasture,
hay or silage
20. Provision of High Quality Protein
50-80% of absorbed N is from microbes
Improved microbial efficiency will provide
more microbial protein
Can get over 3 kg of microbial protein per
day in cattle
High biological value protein source
Amino acid pattern is very similar to that
required by the ruminant animal
21. Microbes As A Feed Source
Microbes as a feed source
Bacteria and protozoa washed out of the
rumen to omasum and into the abomasum
Acidic environment kills microorganisms
Digested and absorbed the same as any other
feed source in stomach and small intestine
Provide amino acids and some energy
22. Energy
Sources of energy leaving rumen:
VFA 70%
Microbial cells 10%
Digestible unfermented feed 20%
No glucose available for the ruminant
Concentration of VFA
in rumen = 50 to 125 uM/ml
23. Provision Of B Vitamins
Meets the ruminant’s requirements
under most conditions
Some supplementation of specific vitamins,
such as niacin, may be beneficial in early
lactation dairy cows
24. Detoxification Of Toxic Compounds
Many potential toxins are de-toxified by
rumen microbes
Example:
Mimosine in Leucaena causes problems
Poor growth, reproduction and hair loss
Hawaiian ruminants, but not those from Australia,
have microbes that degrade mimosine so Leucaena
could be fed
Transferred rumen fluid obtaine from Hawaiian
cattle to Australia
Inoculated rumens of Australian cattle
Fed Leucaena safely to Australian ruminants!
25. Symbiotic Relationship
Ruminants provide to microbes
Housing
Garbage removal
Nutrients
Optimal environment for growth
26. Housing
Reliable heat (39 ± 2°C)
Fluid environment (requires free water intake)
85 to 90% water
Guaranteed housing for 18 to 96 hours
depending on diet and type of animal
Straw-fed water buffalo – longest rumen residence
time for microbes
Small selective browsers (mouse deer or duiker) –
shortest residence time for microbes
27. Garbage Removal
Absorption of VFA
Energy to ruminant
Eructation
CO2 and CH4
Passage of indigestible residue and
microbes to lower GI tract
Rumen mixing to separate and settle small
particles
28. Nutrients
Substrates come from feedstuffs that
animal consumes
Saliva provides urea (N source for
bacteria)
29. Optimal Environment For Growth
Reduced environment (little to no oxygen)
Strict anaerobic microbes in rumen interior
Functional anaerobes near rumen wall
pH 6.0 to 7.0
Saliva contains bicarbonate and phosphate
buffers
Cows produce up to 50 gallons of saliva daily
Continuously secreted
More added during eating and rumination
Cow ruminates 10-12 hours/day
Decreases in particle size of forage reduce need for
rumination, decrease chewing time, decrease saliva
production, and rumen pH plummets
30.
31. Optimal Environment (pH)
If pH 5.7 rather than 6.5
50% less microbial synthesis
Cellulolytic bacteria function best at pH ~6.8
Rate of structural carbohydrate use is decreased
Amylolytic bacteria function best at pH ~5.8
More lactate and less acetate is produced
Further downward pH spiral
In concentrate selectors (like deer), parotid
salivary glands are 0.3% of body weight
32. Symbiotic Relationship
Microbes provide to the ruminant
Digestion of cellulose and hemicellulose
Provision of high quality protein
Production of VFA
Provision of B vitamins
Detoxification of toxic compounds
Ruminants provide to microbes
Housing
Garbage removal
Nutrients
Optimal environment for growth
33. Microbes
% of mass Generation No./mL
interval
Bacteria 60-90 20 min 25-80
billion
Protozoa 10-40 8-36 h 200-500
thousand
Fungi 5-10 24 h minimal
34. Rumen Microbes
Bacteria
>200 species with many subspecies
25 species at concentrations >107/mL
1010 to 1012 cells/mL
99.5% obligate anaerobes
35. Environmental Niches for Bacteria
Groups of bacteria in the rumen
Free-living in the liquid phase
Loosely associated with feed particles
Firmly adhered to feed particles
Associated with rumen epithelium
Attached to surface of protozoa and fungi
Bacteria attached to rice straw
in water buffalo rumen
36. Benefits of Bacterial Attachment
Allows bacteria to colonize the digestible surface of
feed particles
Brings enzymes (from microbes) and substrate (from
feedstuff) together
Protects microbial enzymes from proteases in the rumen
If attachment prevented or reduced, digestion of
cellulose greatly reduced
Retention time of microbes in the rumen is increased to
prolong digestion
Reduces predatory activity of protozoa
Over-feeding fat to ruminants can coat forages, reducing
bacterial attachment
37. Microbial Populations
Cellulolytic bacteria (fiber digesters)
Digest cellulose and hemicellulose
Require pH 6-7
Utilize N in form of NH3
Require S for synthesis of sulfur-containing amino
acids (cysteine and methionine)
Produce acetate, propionate, little butyrate,
CO2
Predominate in rumens of cows fed roughage
diets
38. Microbial Populations
Amylolytic bacteria
Digest starches and sugars
Require pH 5-6
Utilize N as NH3 or peptides
Produce propionate, butyrate and lactate
Predominate in rumens of cows fed grain diets
Rapid change to grain diet causes lactic acidosis
(rapidly decreases pH)
39. Microbial Populations
Methane-producing bacteria
Produce methane (CH4)
Utilized by microbes for energy
Represent loss of energy to animal
Released by eructation
40. Rumen Microbes
Protozoa
Large (20-200 microns) unicellular
organisms
Ingest bacteria and feed particles
Engulf feed particles and digest
carbohydrates, proteins and fats
Numbers affected by diet
42. Rumen Microbes
Fungi
Existence known for about 25 years
Numbers usually low
Digest recalcitrant fiber
Protozoal organisms
attached to red clover
in rumen of steer 24
hours after feeding
43. Dietary Factors That Reduce
Microbial Growth
Rapid, dramatic ration changes
Takes 3-4 weeks for microbes to stabilize
Restricted amounts of feed
Excessive unsaturated fat
Bacteria do not use fat for energy
Inhibit fiber digestion and microbial growth
Different types of fat have different effects
44. Dietary Factors That Reduce
Microbial Growth
Excessive non-structural carbohydrate
Lowers rumen pH (rumen acidosis)
Slug feeding
Feed barley or wheat (rapidly fermented)
To prevent acidosis, must balance lactate users
and producers
45. Dietary Factors That Maximize
Microbial Growth
Maximum dry matter intake
Balanced carbohydrate and protein
fractions at the same time
Bacteria need both energy and N for amino
acid synthesis
Gradual ration changes
Feed available at all times
Maintains stable rumen pH