Transcript Functions of the Rumen

Animal Nutrition
Mc Donald, Greehalgh and Warner. 1987. Animal
Nutrition. Longman
‫تغذيه دام‬
Remember…
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Water
Carbohydrates
Lipids
Protein
Minerals
Vitamins
WATER (H20)
Water (H2O)
• Overlook when formulating rations—assumed
animals have access to good quality water
– EXTREMELY IMPORTANT
• Cheapest & most abundant nutrient
• May lose 100% of body fat, 50% of body protein
and live
• Lose 10% of body water, dehydration occurs
and may result in death
Water (H2O)
• 65-85% of body weight at birth
• 45-60% of body weight at maturity
• Many tissues contain 70-90% water
Functions of Water
1. Transport of nutrients and excretions
2. Chemical reactions and solvent
properties
3. Body temperature regulation
4. Aids in cell shape maintenance
5. Lubricates and cushions joints and
organs
Sources of Water
1. Drinking water
2. Water in feed
3. Metabolic water
Sources of Water
1. Drinking
– Pigs = 1.5-3 gal/hd/day
– Sheep = 1-3 gal/hd/day
– Cattle = 10-14 gal/hd/day
– Horses = 10-14 gal/hd/day
– Poultry = 2 parts water:1 part feed
Sources of Water
2. Water contained in feeds
• Highly variable in feedstuffs
• Grains = 9-30% water
• Forages
– Hay <5%
– Silage 65-75%
– Lush young grass >90%
Calculating Water Content of
Feedstuffs
• 100 lbs of silage (65% moisture) contains
how much actual feed?
• 100 lbs * .65 = 65 lbs of water
• 100 lbs – 65 lbs = 35 lbs of feed
Sources of Water
3. Metabolic Water
- Results from the oxidation of organic
nutrients in the tissues
- 1 g of carbohydrates = .6 g of water
- 1 g of protein
= .4 g of water
- 1 g of fat
= 1 g of water
-
May account for 5-10% of total water
intake
Sources of Water Loss
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Urine
Feces
Lungs
Skin
Milk
Factors Affecting Water Intake
• Temperature & humidity
• Dietary factors
– High moisture feeds reduce drinking
– Fiber, DM intake, salt, and protein
increase drinking
• Lactating vs dry
• Water quality
Water Absorption
• Readily absorbed
– Monogastrics/Ruminants: Jejunum, Ileum,
Cecum, Large Intestine
– Ruminants: Rumen and Omasum
Dry Matter (DM)
Bahan Kering (BK)
DM in the feeds or diets
• DM content in feeds or diets
• How to analyze ?
• How to calculate ?
• What is its effect on feed quality (nutrient
content and preservation)?
• What kind of nutrients contained in the
feeds or diets?
• Remember !!!!
− DM content and Feed Price?
− DM content and Feed Handling?
Feeds or diets DM for animal
• DM content in feeds or diets for animal
• Function ?
• How to calculate ?
CARBOHYDRATES (CHO)
Carbohydrates (CHO)
• Primary component found in livestock feeds
– 70% of DM of forages
– 80% of DM of grains
• Serve as source of energy or bulk (fiber) in the
diet
– Not ESSENTIAL nutrients
• Synthesized by animals
Carbohydrates (CHO)
• Definition: Hydrates of carbon formed by
combining CO2 and H2O
– photosynthesis
Types of CHO
• Monosaccharides: 1 sugar molecule
– Glucose
• Primary sugar body uses for fuel
– Fructose
• Found in honey (75%), fruits, and cane sugar
• Sweetest sugar
• Present in low concentrations in animal
feedstuffs
Monosaccharide (Glucose)
Types of CHO
• Disaccharides: 2 sugar molecules linked by a
glycosidic bond
– Lactose (galactose + glucose)
• Milk sugar
– Sucrose (fructose + glucose)
• Table sugar
• Present in higher concentrations in animal
feedstuffs
Disaccharide (Sucrose)
Types of CHO
• Oligosaccharides: group of CHO
consisting of 2-10 sugar groups
• Present in feed ingredients
– Fructooligosaccharides (Inulin): present
Jerusalem artichokes
– Galactooligosaccharides: present in
soybeans
Types of CHO
• Oligosaccharides
– Not hydrolytically digested or digested
by the action of mammalian enzymes
– Fermented by beneficial bacteria
present in GIT
– “Functional Feed Ingredient”: foodstuffs
which, apart from their normal nutritional
value, are said to help promote or
sustain healthiness
• PREBIOTIC
Soybean Oligosaccharides
Fructooligosaccharides (Inulin)
Types of CHO
• Polysaccharides: many sugar
molecules linked by a glycosidic bond
– Starch: storage form in plants
– Cellulose: most abundant CHO in nature
– Hemicellulose: principle component of
plant cell wall
Polysaccharides
Function of CHO
• Source of energy
• Source of heat
• Building block for other nutrients
Sources of CHO
• Cereal Grains
– Most feedstuffs of plant origin are high in
CHO content
CHO Digestion
• Dietary CHO must be converted to be absorbed
– Simple sugars (monosaccharides)
• How?
– Action of amylase enzyme
• Salivary amylase (swine, poultry)
• Intestinal amylase
– Action of other disaccharidases
• Produced by mucosal lining of duodenum
CHO Digestion
• Mammals do not produce enzymes
necessary to digest oligosaccharides and
celluloses (fibrous feedstuffs)
– Digestion occurs as result of bacterial
fermentation
• Where?
– Rumen
– Large Intestine (cecum and colon)
CHO Digestion
• Fermentation yields:
– CO2
– H 2O
– Heat (heat increment)
– Volatile Fatty Acids (VFA) or also referred
to as Short Chain Fatty Acids (SCFA)
VFA Production
• Serve as 70 - 80% of energy
requirement in ruminants
– VFA’s produced in rumen
• Serve as ~16% of Maintenance energy
requirement in swine
– VFA’s produced in large intestine
VFAs
• Acetate
–  with higher roughage levels
– Produced by cellulolytic & hemicellulolytic
bacteria
VFAs
• Propionate
–  with higher concentrate levels
–  Feed efficiency
– Ionophores increase propionate
production
VFAs
• Butyrate
– Energy source for rumen wall growth
• Papillae growth
– Energy source for colonic cell growth
• monogastrics
VFAs
• Lactate (not volatile)
– Anaerobic conditions
–  rumen and blood pH
– Inhibits most microbial growth
– Acidosis situation
CHO Absorption
• Once simple sugars are formed, they are
absorbed rapidly by small intestine
• Then monosaccharides diffuse into the
portal vein which transports them to sites
of metabolism
VFA Absorption
• Absorbed through the rumen wall or large
intestine mucosa
• Provide energy source to the animal
LIPIDS
Lipids
• Insoluble in water but soluble in organic
solvents
• Dense energy source:
– 1 g fat = 9.45 kcal GE
– 1 g protein = 4.5 kcal GE
– 1 g CHO = 4.2 kcal GE
• Thus, fat produces 2.25 times the energy
than CHO
Lipids
• Triglyceride: primary storage form of
lipids
• Saturated fatty acids: contain no
double bonds
• Unsaturated fatty acids: contain 1 or
more double bonds
Lipids
Lipids
• Fats = solid at room temp = animal
origin
– saturated
• Oils = liquid at room temp = plant
origin
– unsaturated
Functions of Lipids
• Dietary energy supply
• Source of insulation & protection
• Source of essential fatty acids (EFA)
• Carrier for fat soluble vitamins
Lipids
• Essential fatty acids (EFA): Those
fatty acids that an animal requires,
but which it cannot synthesize in
adequate amounts to meet the
animal’s need
– Linoleic
– Linolenic
– Arachidonic
C18:2
C18:3
C20:4
EFA
• Physiological needs:
– Cell membrane structure
– Synthesis of prostaglandins which
control blood pressure and smooth
muscle contractions
• Deficiency:
– Scaly, flaky skin (Poor feather growth)
– Poor growth
Sources of Lipids (EFA)
• Most feeds contain low levels
– > 10%
• Unprocessed oil seeds (soybean, cottonseed,
sunflower seed) contain up to 20% fat
• Traditionally, if additional fat is needed it is
added to the diet
– Animal fats
– Vegetable oils
Lipid Digestion
• Occurs in the small intestine (duodenum)
• Bile produced by liver emulsifies fat
• Pancreatic lipase (enzyme) breaks apart
fat for absorption
Lipid Absorption
• Monoglycerides (MG)—absorbed into SI
mucosal cells
• Free Fatty Acids (FFA)—absorbed into SI
mucosal cells or enter blood circulation
directly
Lipid Absorption
• Very efficient
– Absorption rates range from 70-96%
• Generally, oils (unsaturated fats) are
absorbed more completely that fats
(saturated fats)
Ketosis
• Disorder of metabolism
– Insufficient energy intake in high producing
animals (e.g. Dairy cattle in early lactation and
sheep in late pregnancy)
– Results in catabolism (breakdown) of body
energy (fat) reserves
Ketosis
• 2 C fragments (ketones) of fat catabolism
(breakdown) build up
• Toxic levels cause
– Body weight loss
– Abortion
– Poor milk production
PROTEINS
Proteins
• Principal constituent of organs and soft
tissues
• Highest concentration of any nutrient,
except water, in the body of all living
organisms and animals
• Required for life
Proteins
• DEFINITION: Protein are long chains of
amino acids (AA)
– Formed by peptide linkages
• Amino group + carbon skeleton
Proteins
Amino Acid (AA)
Protein (2 AA joined by peptide
bond between  carboxyl
and  amino group
Proteins
• Dietary requirements highest in young,
growing animals and declines at maturity
• Large molecules that vary greatly in in
size, shape, and function
– MW = 5000 to millions
Categories of Protein
1. Essential Amino Acids (EAA):
– required in the diet
– cannot be synthesized at a rate sufficient to
meet the nutritional requirements
Essential AA
• PTV TIM HALL (KNOW!)
•
Phenylalanine
•Threonine
• Histidine
•Valine
• Arginine
• Lysine
•
Tryptophan
• Isoleucine
• Methionine
• Leucine
Categories of Protein
2. Nonessential AA
– animal can produce enough to meet it’s
requirements
3. Semi-essential AA
– Animal can not always produce enough to
meet its requirements
Functions of Protein
• Basic structural units
– Collagen, blood, elastin
• Body metabolism
– Enzymes, hormones, immune system,
hereditary transmission
• Production
– Meat, milk, skin/hair
Protein Deficiency
• Reduced growth & feed efficiency
• Infertility
• Reduced birth weights
• Reduced milk production
Sources of Protein
• Most common feedstuffs contain some
protein (the quality is another issue)
• KEY: to combine feedstuffs into the diet
so that AA requirements are met
– e.g. Using a corn-soybean meal diet for pigs
Protein Digestion
• Proteins must be broken down into AA for
absorption in the GIT
– Exception! Early in life (> 48 h after birth)
proteins from milk (immunoglobulins) can be
absorbed intact across the intestinal
epithelium
Protein Digestion/Absorption
in Monogastrics
Monogastric Protein Digestion
• Stomach: HCl unfolds (denatures) proteins
and activates pepsinogen secreted by
stomach to pepsin
– Pepsin begins protein digestion to peptides
(short-chain proteins)
• Small intestine: enzymes (trypsin) break
peptides into AA
Monogastric Protein
Absorption
• AA are absorbed in anterior part of the
small intestine
– Jejunum and ileum
• AA are absorbed and transported to tissue
via blood
Protein Digestion and
Absorption in Ruminants
Ruminant Protein Digestion
• In rumen, microbes break down protein to
peptides and AA and then degraded
further to ammonia, VFAs, and carbon
dioxide
• Ammonia and/or NPN (urea) + CHO
source form microbial proteins
Ruminant Protein Absorption
• Protein can be absorbed through rumen
wall as ammonia
• Microbial proteins pass to the lower
intestine where they are converted to AA
and absorbed
Fates of Absorbed AA
1. Tissue protein synthesis
2. Synthesis of enzymes, hormones & other
metabolites
3. Use for energy (inefficient energy source)
MINERALS
Minerals
• Inorganic components of the diet
• Can not be synthesized or decomposed by
chemical reactions
• Total mineral content is called “ash”
• Makes up 3-5% of the body weight
Categories of Minerals
• Macro Minerals: Minerals normally present at
greater levels in animal body or needed in large
amounts in the diet (found in concentrations >
100 ppm)
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Calcium (Ca)
Phosphorus (P)
Sodium (Na)
Chloride (Cl)
Magnesium (Mg)
Potassium (K)
Sulfur (S)
Categories of Minerals
• Micro (Trace) Minerals: Minerals normally present at low
levels in animal body or needed in small amounts in the
diet (found in concentrations < 100 ppm)
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Cobalt (Co)
Copper (Cu)
Fluoride (Fl)
Iodine (I)
Iron (Fe)
Manganese (Mn)
Molybdenum (Mo)
Selenium (Se)
Zinc (Zn)
General Mineral Functions
• Skeletal formation and maintenance (Ca, P, Mg,
Cu, Mn)
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Protein synthesis (P, S, Zn)
Oxygen transport (Fe, Cu)
Fluid balance—osmotic pressure (Na, Cl, K)
Acid-base balance regulation (Na, Cl, K)
Activators or components of enzyme systems
(Ca, P, K, Mg, Fe, Cu, Mn, Zn)
• Mineral-Vitamin relationships (Ca, P, Co, Se)
Macro Mineral Deficiencies
• Ca and P
– Inadequate bone mineralization
• Rickets (young)
• Osteomalacia (adult)
– Phytate P—bound and unavailable to nonruminants
• Mg
– Grass tetany-convulsions, coma, death
• Likely in grazing, lactating females in early spring or fall
• Mg is there in the plant, just in bound form due to lack of sunlight
Macro Mineral Deficiencies
• Fe
– Anemia (insufficient hemoglobin)
– Young pigs (rapid growth, low stores, low Fe
in milk)
Trace Mineral Deficiencies
• Mn
– Poor growth
– Poultry—Perosis—deformed and enlarged
hock joints
• I
– Goiter—swollen thyroid
Trace Mineral Deficiencies
• Cu
– Fading hair coat color (depigmentation)
– Low Cu utilization may result when excess Mo or Zn
• Zn
– Parakeratosis (dermatitis-thickening of skin)
– Poor hair or feather development
– Exacerbated by high Ca
Trace Mineral Deficiencies
• Se
– White muscle disease-nutritional muscular
dystrophy
• Muscle appears white due to Ca-P deposits
– Due to low concentration of Se in soil
Mineral Toxicities
• Usually not a problem ($)
• NaCl can be for swine and poultry
– Levels above 8%--causes nervous disorders
• Cu a big problem for sheep and young animals
– Mineral mixes for other species/age groups used
• Se has a small margin between requirement (0.3
ppm) & toxicity (8 ppm)
– Plants grown in regions of high soil Se
Sources of Minerals
• Forages usually considered good sources
of minerals
– Largely dependant on soil conditions
• Grains are fair source of P, but low in
other minerals
• Mineral premixes
• Mineral blocks
Mineral Absorption
• Minerals are converted to their ionic form
and absorbed in the small intestine
Vitamins
• Organic substances required by the animal in
very small amounts
• Necessary for metabolic activity but not part of
body structure
• Content varies greatly in the feed
• Requirements depend on species
– Monogastrics = a lot b/c cannot synthesize
– Ruminants = few vitamins due to microbial synthesis
Types of Vitamins
• Fat-soluble vitamins
– Vit A (carotene): vision
– Vit D: Ca, P absorption
– Vit E (tocopherol): antioxidant
– Vit K (menadione): blood clotting
• Short shelf life (3-4 months)
• Need lipids for absorption
• Destroyed by heat, minerals
Types of Vitamins
• Water-soluble vitamins
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Thiamine
Riboflavin
Niacin
Pyridoxine
Pantothenic acid
Biotin
Choline
Folic acid
Vitamin B12
Vitamin C
B Complex Vitamins
Vitamin Functions
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Reproduction
Fetal Development
Colostrum Production
Milk production
Wool
Egg
Racing
Vitamin Deficiencies
• Vitamin A
– Xerophtalmia: night blindness
– Poor growth, reproductive failure
• Vitamin D
– Rickets
– Osteomalacia
• Vitamin K
– Poor blood clotting/hemorrhaging
Vitamin Deficiencies
• Vitamin C
– Scurvy: slow wound healing, spongy gums,
swollen joints, anemia
• B Complex Vitamins
– Reduced growth/poor appetite
– Dermatitis
– Muscular incoordination
Most likely deficient…
• In practical situations:
– Ruminants: A, E, D (limited circumstances)
– Swine: riboflavin, niacin, pantothenic acid,
choline, B12, A, D, and sometimes E
– Poultry: All vitamins except Vitamin C,
inositol, and PABA
Vitamin Toxicity
• Unlikely ($)
• Generally nontoxic
– Exceptions:
• A, D, Niacin, Pyridoxine, Choline
Sources of Vitamins
• A: green, leafy forages, corn, fish oil
• D: fish oils, sun-cured hay
• E: seed germ oils, green forage or hay
• K: green forage, fish meal, synthetic menadione
Sources of Vitamins
• B Vitamins: green forages usually
– Niacin: present in grains, but unavailable to
nonruminants
• B12: protein feeds of animal origin, fermentation
products
• C: citrus fruits, green, leafy forages, well-cured
hay
Sources of Vitamins
• Most nonruminants rations contain a
vitamin premix
– Consume basically no forages and B vitamins
are poorly available from cereal grains
Vitamin Absorption
• Most vitamins are absorbed in the upper
portion of the small intestine
• Water soluble vitamins are rapidly
absorbed
• Fat soluble vitamin absorption relies on fat
absorption mechanisms
Nutrition
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Nutrition
–
provide animals with nutrients to enable them to:
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maintain
reproduce
lactate
work
grow
lay eggs
produce wool
PROFIT – feed animals adequately & economically
first must understand process of digestion and
absorption of nutrients from feeds
Animal Classification By Type of Food
Consumed
•
Herbivore - Depends entirely on plant food
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•
Carnivore – Almost entirely on meat for food
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•
Sheep, Cattle, Horses
Dog
Omnivore – Both meat and plants for food
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Swine, Chickens, Humans
Animal Classification By Type Digestive
System
•
Major differences in anatomy and
physiology of digestive tracts of different
species
•
Affects nature of digestive processes and
the kind of feed that can be utilized by the
animal
•
Based upon type of digestive tract, 4
different classifications can be made.
Animal Classification By Type Digestive
System
Monogastrics – Major Category
• 1. Simple Stomach – Pigs, Humans, Dogs
• 2. Avian – Chickens, Turkeys
• 3. Pseudo Ruminants – Horses, Rabbits
Ruminants – Cattle, Sheep, Goats
Swine: - “Simple stomach”, Limited capacity
-Chemical secretions and enzymes are
critical for digestion
-limited microbial action, limited fiber
digestion
Figure 6–3: Swine digestive tract.
Digestive System Parts and Functions Swine
• Mouth – Initial breakdown of food, mechanical, amylase in
saliva, some lipase
• Stomach – Initial digestion of food, broken to smaller particles
-Hydrochloric acid – HCl, breaking of bonds
-Pepsin – proteins to polypeptides
Digestive System Parts and Functions Swine
•Small Intestine – Further breakdown and absorption of food
Pancreatic Enzymes
-Lipase - fats to fatty acids and glycerol
-Trypsin - polypeptides to peptides
-Chymotrypsin – peptides to amino acids
-Amylase – starch to disaccharides
-Sucrase, Maltase, etc. – disaccharides to monosaccharides
Reduced particles are absorbed into the bloodstream across wall of
the small intestine. Diffusion = passive, Transport = active.
Digestive System Parts and Functions Swine
•Cecum/Large Intestine – limited plant fiber digestion
-microbes present produce the enzyme cellulase
-cellulase breaks down cellulose (one type of plant fiber)
-very inefficient system in monogastrics (except horses)
Avian – monogastric,
similar to others except:
-different anatomy since
no teeth to chew food
-Limited capacity
-Chemical secretions and
enzymes are critical for
digestion
-Limited microbial action
-Limited fiber digestion
Figure 6–7: Digestive system of the avian.
Digestive System Parts and Functions Avian
• Beak – procure food
• Crop – feed directly here from esophagus
-feed stored and soaked with water
• Proventriculus – True “stomach” in Avian species, adds and
mixes in:
-Hydrochloric acid – HCl, breaking of bonds
-Pepsin – proteins to polypeptides
Digestive System Parts and Functions Avian
•Gizzard – Contains grit, food is crushed and ground to smaller
particles by strong muscular contractions.
•Small Intestine – Same as swine
•Cecum/Large Intestine – Same as swine
Ruminants: 4 compartment “stomach”
-Designed for fiber digestion with a high capacity
-microorganisms in rumen to digest fiber – symbiotic relationship
Capacities of different parts?
80%
8%
9%
Figure 6–4: Digestive system of the ruminant.
5%
Digestive System Parts and Functions Ruminants
Mouth – like swine, no enzymes
Stomach compartments
1. Reticulum (honeycomb)
- hardware disease?
2. Rumen (fermentation vat)
Digestive System Parts and Functions Ruminants
Functions of the Rumen:
•
Vat contains slurry of fluid, grain (bottom), boluses of forage
and microorganisms
•
Microorganisms are bacteria and protozoa, type changes with
type of feed consumed (grain vs forages)
•
In animals consuming forages, microbes present will break
down the plant fiber and:
- Produce energy to be absorbed through the rumen as
VFAs
- Synthesize more microbes (comprised mainly of
protein) that are digested as a source of protein for the
animal
- Synthesize ALL essential amino acids and B Vitamins
Digestive System Parts and Functions Ruminants
Functions of the Rumen - continued:
•
Major VFAs are Acetate, Propionate and Butyrate
•
Process of digestion of food by microbes is fermentation
•
Rumination is regurgitation of forage boluses from rumen
and reticulum
•
Eructation is the belching of gases (CO2 and Methane)
produced by the fermentation process – bloat
Digestive System Parts and Functions - Ruminants
Is the rumen
functional in
newborn
ruminants???
Figure 6–5: Side view (right side) of the rumen.
Digestive System Parts and Functions Ruminants
Stomach compartments - continued
3. Omasum (manyplies)
- adds water to or absorbs water from rumen
contents
4. Abomasum (true stomach)
-performs very similar functions as in monogastric
animals
Digestive System Parts and Functions Ruminants
•Small Intestine – Similar to swine
•Cecum/Large Intestine – Similar to swine
Pseudo Ruminants: Monogastric, single compartment stomach
• have a greatly enlarged cecum.
• have a large amount of “hind – gut” fermentation.
•
digest fiber, can use forages as part of diet
Digestive System Parts and Functions Horses
Functions of the Cecum
•
microbes present break down the plant fiber:
- Produce energy to be absorbed through the cecum as VFAs
– less efficient than rumen
-
Synthesize more microbes, vitamins and amino acids, not digested
and used since cecum is downstream of digestive organs (stomach
and small intestine) – Some are absorbed
-
Require higher quality feed and forage
Nutrients
6 major classes
1.
2.
3.
4.
5.
6.
Water
carbohydrates lipids proteins
vitamins
minerals
Energy
Figure 5–1: The essential nutrients.
1Mnemonic device for remembering essential amino acids 5 MATT HILL VP.
2For poultry, two additional amino acids are needed: glycine and proline.
3Arachidonic acid can be synthesized from linoleic acid if it is available so it is
only essential if linoleic acid is absent or in short supply.
4Authors vary on whether or not to list sulfur as a macromineral or
micromineral. The discrepancy arises because only a very small amount of
inorganic S is needed but the sulfur-containing amino acids (organic S) are
needed in larger quantities.
Nutrients
1. Water
–
Functions:
a. part of metabolic reactions
b. transports nutrients
c. temperature regulation
–
moisture in feed?
• % in grazed forages, silage, hay, corn?
Nutrients
2. Carbohydrates
a. Types:
• simple = starches & sugars
• complex = cellulose (plant cell walls = fiber)
b. Function:
source of energy
• monogastrics – from grains or cecum (horses)
• ruminants – from volatile fatty acids
Nutrients
3. Lipids (fats & oils)
–
–
–
most feeds contain 1-5% fat or oil
composed of 3 fatty acids & glycerol
Functions:
a. energy source
• 2.25 x more energy than carbohydrates
Nutrients
4. Proteins
–
25 amino acids are building blocks of animals
–
10 essential amino acids – not synthesized by body
tissues
• Provided by microbial synthesis in ruminants
• Must be in diet of all monogastrics
• 1st limiting = LYSINE
–
only nutrient containing nitrogen (16%)
Nutrients
Figure 5–1: 1Mnemonic device
for remembering essential
amino acids 5 MATT HILL VP.
Nutrients
Function of Proteins
•
supply amino acids for body proteins
- muscle; bone; connective tissue; hormones;
enzymes; antibodies; milk components; cell repair
small amounts for specific body
functions
a. 2 classifications
1. water soluble – C & Bcomplex (see Fig 5-1)
– microbes synthesize in
ruminants & horses
2. fat soluble – A, D, E, K
– A & E required in
diets of all animals
– D – produced by
effects of sun on skin
– K – synthesis by
rumen/cecum
microbes
Nutrients
5. Vitamins
b. Functions:
1. enzyme cofactors; blood clotting; bone health;
health of internal linings of body
2. deficiencies lead to specific disorders
Example Disorders:
blood clotting
=K
scurvy
=C
6. Minerals
–
inorganic
(contain no
carbon); are
elements
Nutrients
Mineral Functions
-part of some amino acids & vitamins; metabolic
reactions; enzyme function; body structure; transport
oxygen
Deficiency examples:
White muscle
=selenium
Grass Tetany
=magnesium
Rickets
=calcium
White hair on black cattle
=copper
Anemia
=iron
Retained Placenta
=selenium and Vitamin E
• Slides after this point not used in 2002
lectures.
• STUDENTS – you are not responsible for
the information beyond this point on the
exam.
Figure 5–9: Schematic diagram for partitioning energy values of feeds.
(Source: Adapted from Wagner, 1977. Used with permission.)
Nutrient Requirements for
Maintenance, Growth, and Production
•
Feed animals to meet nutrient requirements
for:
1. maintenance – (about ½ of feed meets this)
•
•
no growth or production
met before supplying any other body function
Nutrient Requirements for
Maintenance, Growth, and Production
2. growth
– increase number and(or) size of cells
– protein synthesis > protein breakdown
– build muscle, bone, connective tissue
Nutrient Requirements for
Maintenance, Growth, and Production
3.
production
– fattening/finishing
– reproduction
– lactation
– egg laying
– work
– wool
Digestion in the Ruminant
Digestion in the Ruminant
Largest % of herbivores
I. Main fxn of complex
stomach of ruminant
•
•
Utilize the largest CHO
source in the world as an
energy source
Produce food and other
products
Anatomy
Large
Intestine
Cecum
Esophagus
Rumen
Mouth
Reticulum
Small
Intestine
Abomasum
Omasum
Digestion in the Ruminant
A. Mouth
1. No upper teeth
2. Dental pad
Digestion in the Ruminant
A. Mouth
1. No upper teeth
2. Dental pad
3. Particle size reduction by teeth grinding
against dental pad
4. Saliva
1. Moistens food
2. More importantly provides buffer for rumen
3. Rumen microorganisms produce
Volatile Fatty ACIDS
Digestion in the Ruminant
B. Esophagus –
A. Same general fxn as in monogastric
C. Complex stomach comprised of four
compartments
1. Rumen
a. Contents = ~20% BW of animal
b. Volume –
•
•
5 – 60 gallons liquid
5 – 50 lb dry material
Digestion in the Ruminant
Stomach complex con’t
2. Reticulum
3. Omassum
4. Abomasum
a. True glandular stomach
b. Lined with mucous membrane and gastric juice
secreted
Digestion in the Ruminant
D. Rumen/reticulum and omassum
collectively term:
 Forestomachs 
– Lining of these tissues:
•
Stratified squamous epithelium
– “layered, scaly” epithelium
•
Not glandular
– No secretions
Digestion in the Ruminant
E. Esophageal groove (reticular groove)
1. Groove which can contract and form tube to
bypass rumen/reticulum
2. Empties into omasum
3. Fxn =
a. Allow milk to pass directly to omasum and
abomasum
b. Keep milk out of young ruminant’s undeveloped
rumen
Digestion in the Ruminant
III.
Rumen - Anatomy/Function
A.
Main fxn = act as site of anaerobic bacterial
fermentation
1.
2.
Anaerobic microorganisms live and reproduce
No oxygen = anaerobic
B.
Undeveloped at birth – sterile
C.
Partially developed at 4-6 weeks of age
D.
1st place food goes in adult
E.
Some nutrients bypass anaerobic fermentation
Digestion in the Ruminant
F. Rumen wall covered with papillae
1. Small finger-like projections.
2. Increase surface area.
3. Influence by diet and season.
G. Storage of food
1. Consume large amounts can digest later.
– Regurgitation, remastication, etc.
Digestion in the Ruminant
IV. Microorganisms in the rumen digest
CHO – cellulose and starch
a.

Fermentations produces Volatile Fatty Acids
Fiber (cellulose)
Corn (starch)
MO’s
VFA’s
Digestion in the Ruminant
b.
VFA’s
a.
b.
c.
H
Acetate/acetic acid (2 carbons)
Propionate/propionic acid (3 carbons)
Butyrate/butyric acid (4 carbons)
OH
H C C
H
c.
H
H C
O
H
H
OH
C C
H
H
H C
O
H
H H
OH
C C C
H H
O
VFA’s absorbed through rumen wall
Can supply 50-100% of required energy for ruminant
Digestion in the Ruminant
d. Main benefit of microbial fermentation
•
Produce microbial protein as they live and
reproduce
Urea
Protein
NH3
MCO protein
C skeleton
VFA’s
AA
•
•
Utilize urea (non-protein source)
Utilize plant/animal protein
Digestion in the Ruminant
e. Bacteria pass through rumen with feed to lower
G.I. Tract
– Protein (feed and microbial)
f. Microbial protein contains ~50% CP
•
Excellent protein source
g. Microorganism also synthesize:
1. B vitamins – thus no req’t
2. Vitamin K
h. Microorganism also contain:
1. 1 – 2 % CHO
2. 3% fat – essential FA’s present – no req’t for FA
Digestion in the Ruminant
V.
Rumen provides favorable environment for
microbial growth due to:
a.
b.
c.
d.
e.
f.
Buffered pH
Temperature maintained at 101 to 103
degrees
Primarily a liquid media
Food supply replenished daily
End products of digestion removed
Anaerobic
Digestion in the Ruminant - 2
Anatomy – continued
I.
Reticulum – Honey Comb
A.
1.
Fxn – Site of microbial action & absorption of VFA’s
2.
Fxn – Pacemaker for rumen contractions
a. Contractions start in reticulum spread to rumen
b. Mixes rumen contents
Digestion in the Ruminant - 2
Anatomy – continued
I.
A.
Reticulum – Honey Comb
c. Heavy particles move to bottom, lighter ones float
d. Lighter particles subject to rumination
Rumination = regurgitation, remastication,
resalivation, reglutition
Digestion in the Ruminant - 2
• Omasum – “many piles”, lamina propia
–
–
–
–
Fxn is unclear
Some water and VFA absorption
Some mechanical digestion from lamina
Regulates particle size flowing to abomasum/S.I.
• Abomasum
– True stomach
– Secretions
• HCI – denatures protein, but also kills MCO
• Mucin, pepsin, etc
Digestion in the Ruminant - 2
d. Small intestine, large intestine
– Very similar to that for non-ruminant
e. Post Gastric Fermentation
1. Approximately 5-15% of cellulytic digestion can
occur in colon and cecum
2. MCO here as well but lost in feces, lose MCO
protein
3. VA’s produced and can be absorbed through L.I.
4. Primary function is still water absorption
Rumination Process
Rumination Process
Define = set of steps that reduce particle size of
digesta for passage to lower tract
1. Regurgitation
a. Bolus is moved by reverse contraction of esophagus
from rumen to mouth
2. Remastication
a. Reduce particle size
3. Resalivation
a. Buffer
b. Nitrogen recycling
4. Reglutition
8 hr
per day
Eructation
1. Process of removing gas from the rumen
a. 50 – 200 liters/day
b. Gases produced :
H2 – hydrogen
CO2 – carbon dioxide
CH4 – methane
H2S – hydrogen sulfide
Eructation
c. Rumen contraction forces gas to the back and
then forward
d. Gas forced up esophagus to the trachea
Eructation
2. Problem = Bloat
a. Primarily caused by inability to eructate
a. Froth
b. Foam
b. Secondarily caused by something
anatomically wrong
c. Commonly seen distention of left side
Bloat
Eructation
2. Problem = Bloat
a. Primarily caused by inability to eructate
a. Froth
b. Foam
b. Secondarily caused by something anatomically
wrong
c. Commonly seen distention of left side
d. Legumes (soluble protein) – primary cause
e. “Barn door left open” – wheat pasture, lush grass
f. Treatment/prevention
a. Trochar
b. Ionphores