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Animal Nutrition Mc Donald, Greehalgh and Warner. 1987. Animal Nutrition. Longman. تغذيه دام. Remember…. Water Carbohydrates Lipids Protein Minerals Vitamins. WATER (H 2 0). Water (H 2 O). Overlook when formulating rations—assumed animals have access to good quality water

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animal nutrition mc donald greehalgh and warner 1987 animal nutrition longman

Animal NutritionMc Donald, Greehalgh and Warner. 1987. Animal Nutrition. Longman

تغذيه دام

  • Water
  • Carbohydrates
  • Lipids
  • Protein
  • Minerals
  • Vitamins
water h 2 o
Water (H2O)
  • Overlook when formulating rations—assumed animals have access to good quality water
  • 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 h 2 o1
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
Functions of Water
  • Transport of nutrients and excretions
  • Chemical reactions and solvent properties
  • Body temperature regulation
  • Aids in cell shape maintenance
  • Lubricates and cushions joints and organs
sources of water
Sources of Water
  • Drinking water
  • Water in feed
  • Metabolic water
sources of water1
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 water2
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
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 water3
Sources of Water
  • 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
Sources of Water Loss
  • Urine
  • Feces
  • Lungs
  • Skin
  • Milk
factors affecting water intake
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
Water Absorption
  • Readily absorbed
    • Monogastrics/Ruminants: Jejunum, Ileum, Cecum, Large Intestine
    • Ruminants: Rumen and Omasum
dm in the feeds or diets
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
Feeds or diets DM for animal
  • DM content in feeds or diets for animal
  • Function ?
  • How to calculate ?
carbohydrates cho1
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 cho2
Carbohydrates (CHO)
  • Definition: Hydrates of carbon formed by combining CO2 and H2O
    • photosynthesis
types of cho
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
types of cho1
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
types of cho2
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 cho3
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
types of cho4
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
function of cho
Function of CHO
  • Source of energy
  • Source of heat
  • Building block for other nutrients
sources of cho
Sources of CHO
  • Cereal Grains
    • Most feedstuffs of plant origin are high in CHO content
cho digestion
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 digestion1
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 digestion2
CHO Digestion
  • Fermentation yields:
    • CO2
    • H2O
    • Heat (heat increment)
    • Volatile Fatty Acids (VFA) or also referred to as Short Chain Fatty Acids (SCFA)
vfa production
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
  • Acetate
    •  with higher roughage levels
    • Produced by cellulolytic & hemicellulolytic bacteria
  • Propionate
    •  with higher concentrate levels
    •  Feed efficiency
    • Ionophores increase propionate production
  • Butyrate
    • Energy source for rumen wall growth
      • Papillae growth
    • Energy source for colonic cell growth
      • monogastrics
  • Lactate(not volatile)
    • Anaerobic conditions
    •  rumen and blood pH
    • Inhibits most microbial growth
    • Acidosis situation
cho absorption
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
VFA Absorption
  • Absorbed through the rumen wall or large intestine mucosa
  • Provide energy source to the animal
  • 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
  • Triglyceride: primary storage form of lipids
  • Saturated fatty acids: contain no double bonds
  • Unsaturated fatty acids: contain 1 or more double bonds
  • Fats = solid at room temp = animal origin
    • saturated
  • Oils = liquid at room temp = plant origin
    • unsaturated
functions of lipids
Functions of Lipids
  • Dietary energy supply
  • Source of insulation & protection
  • Source of essential fatty acids (EFA)
  • Carrier for fat soluble vitamins
  • 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 C18:2
    • Linolenic C18:3
    • Arachidonic C20:4
  • 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
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
Lipid Digestion
  • Occurs in the small intestine (duodenum)
  • Bile produced by liver emulsifies fat
  • Pancreatic lipase (enzyme) breaks apart fat for absorption
lipid 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 absorption1
Lipid Absorption
  • Very efficient
    • Absorption rates range from 70-96%
  • Generally, oils (unsaturated fats) are absorbed more completely that fats (saturated fats)
  • 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
  • 2 C fragments (ketones) of fat catabolism (breakdown) build up
  • Toxic levels cause
    • Body weight loss
    • Abortion
    • Poor milk production
  • 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
  • DEFINITION: Protein are long chains of amino acids (AA)
    • Formed by peptide linkages
  • Amino group + carbon skeleton

Amino Acid (AA)

Protein (2 AA joined by peptide

bond between  carboxyl

and  amino group

  • 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
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
Essential AA
  • Phenylalanine
  • Threonine
  • Valine
  • Tryptophan
  • Isoleucine
  • Methionine
  • Histidine
  • Arginine
  • Lysine
  • Leucine
categories of protein1
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
Functions of Protein
  • Basic structural units
    • Collagen, blood, elastin
  • Body metabolism
    • Enzymes, hormones, immune system, hereditary transmission
  • Production
    • Meat, milk, skin/hair
protein deficiency
Protein Deficiency
  • Reduced growth & feed efficiency
  • Infertility
  • Reduced birth weights
  • Reduced milk production
sources of protein
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
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
monogastric protein digestion
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
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
ruminant protein digestion
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
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
Fates of Absorbed AA

1. Tissue protein synthesis

2. Synthesis of enzymes, hormones & other metabolites

3. Use for energy (inefficient energy source)

  • 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
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)
    • Calcium (Ca)
    • Phosphorus (P)
    • Sodium (Na)
    • Chloride (Cl)
    • Magnesium (Mg)
    • Potassium (K)
    • Sulfur (S)
categories of minerals1
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)
    • Cobalt (Co)
    • Copper (Cu)
    • Fluoride (Fl)
    • Iodine (I)
    • Iron (Fe)
    • Manganese (Mn)
    • Molybdenum (Mo)
    • Selenium (Se)
    • Zinc (Zn)
general mineral functions
General Mineral Functions
  • Skeletal formation and maintenance (Ca, P, Mg, Cu, Mn)
  • 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
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 deficiencies1
Macro Mineral Deficiencies
  • Fe
    • Anemia (insufficient hemoglobin)
    • Young pigs (rapid growth, low stores, low Fe in milk)
trace mineral deficiencies
Trace Mineral Deficiencies
  • Mn
    • Poor growth
    • Poultry—Perosis—deformed and enlarged hock joints
  • I
    • Goiter—swollen thyroid
trace mineral deficiencies1
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 deficiencies2
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
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
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
Mineral Absorption
  • Minerals are converted to their ionic form and absorbed in the small intestine
  • 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
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 vitamins1
Types of Vitamins
  • Water-soluble vitamins
    • Thiamine
    • Riboflavin
    • Niacin
    • Pyridoxine
    • Pantothenic acid
    • Biotin
    • Choline
    • Folic acid
    • Vitamin B12
    • Vitamin C

B Complex Vitamins

vitamin functions
Vitamin Functions
  • Reproduction
  • Fetal Development
  • Colostrum Production
  • Milk production
  • Wool
  • Egg
  • Racing
vitamin deficiencies
Vitamin Deficiencies
  • Vitamin A
    • Xerophtalmia: night blindness
    • Poor growth, reproductive failure
  • Vitamin D
    • Rickets
    • Osteomalacia
  • Vitamin K
    • Poor blood clotting/hemorrhaging
vitamin deficiencies1
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
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
Vitamin Toxicity
  • Unlikely ($)
  • Generally nontoxic
    • Exceptions:
      • A, D, Niacin, Pyridoxine, Choline
sources of vitamins
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 vitamins1
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 vitamins2
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
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
    • provide animals with nutrients to enable them to:
      • maintain grow
      • reproduce lay eggs
      • lactate produce wool
      • work
    • PROFIT – feed animals adequately & economically
    • first must understand process of digestion and absorption of nutrients from feeds
animal classification by type of food consumed
Animal Classification By Type of Food Consumed
  • Herbivore - Depends entirely on plant food

- Sheep, Cattle, Horses

  • Carnivore – Almost entirely on meat for food

- Dog

  • Omnivore – Both meat and plants for food

- Swine, Chickens, Humans

animal classification by type digestive system
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 system1
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
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 swine1
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 swine2
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
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 avian1
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?





Figure 6–4:  Digestive system of the ruminant.

digestive system parts and functions ruminants
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 ruminants1
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 ruminants2
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 ruminants3
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 ruminants4
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
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

6 major classes

  • Water
  • carbohydrates -
  • lipids -
  • proteins
  • vitamins
  • minerals



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.

  • Water
    • Functions:
      • part of metabolic reactions
      • transports nutrients
      • temperature regulation
    • moisture in feed?
      • % in grazed forages, silage, hay, corn?
  • Carbohydrates
    • Types:
      • simple = starches & sugars
      • complex = cellulose (plant cell walls = fiber)
    • Function:

source of energy

        • monogastrics – from grains or cecum (horses)
        • ruminants – from volatile fatty acids
  • Lipids (fats & oils)
    • most feeds contain 1-5% fat or oil
    • composed of 3 fatty acids & glycerol
    • Functions:
      • energy source
        • 2.25 x more energy than carbohydrates
  • 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%)


Figure 5–1:  1Mnemonic device for remembering essential amino acids 5 MATT HILL VP.


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

    • 2 classifications
      • water soluble – C & B-complex (see Fig 5-1)
        • microbes synthesize in ruminants & horses
      • 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
  • Vitamins
    • Functions:
      • enzyme cofactors; blood clotting; bone health; health of internal linings of body
      • deficiencies lead to specific disorders
  • Example Disorders:
  • blood clotting
  • = K
  • scurvy
  • = C


    • inorganic (contain no carbon); are elements

Mineral Functions

-part of some amino acids & vitamins; metabolic reactions; enzyme function; body structure; transport oxygen

Deficiency examples:

White muscle


Grass Tetany




White hair on black cattle




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
Nutrient Requirements for Maintenance, Growth, and Production
  • Feed animals to meet nutrient requirements for:
    • maintenance – (about ½ of feed meets this)
      • no growth or production
      • met before supplying any other body function
nutrient requirements for maintenance growth and production1
Nutrient Requirements for Maintenance, Growth, and Production
  • growth
    • increase number and(or) size of cells
    • protein synthesis > protein breakdown
    • build muscle, bone, connective tissue
nutrient requirements for maintenance growth and production2
Nutrient Requirements for Maintenance, Growth, and Production
  • production
    • fattening/finishing
    • reproduction
    • lactation
    • egg laying
    • work
    • wool
digestion in the ruminant1
Digestion in the Ruminant

Largest % of herbivores

  • Main fxn of complex stomach of ruminant
  • Utilize the largest CHO source in the world as an energy source
  • Produce food and other products












digestion in the ruminant2
Digestion in the Ruminant
  • Mouth
    • No upper teeth
    • Dental pad
digestion in the ruminant3
Digestion in the Ruminant
  • Mouth
    • No upper teeth
    • Dental pad
    • Particle size reduction by teeth grinding against dental pad
    • Saliva
      • Moistens food
      • More importantly provides buffer for rumen
      • Rumen microorganisms produce

Volatile Fatty ACIDS

digestion in the ruminant4
Digestion in the Ruminant
  • Esophagus –
    • Same general fxn as in monogastric
  • Complex stomach comprised of four compartments
    • Rumen
      • Contents = ~20% BW of animal
      • Volume –
        • 5 – 60 gallons liquid
        • 5 – 50 lb dry material
digestion in the ruminant5
Digestion in the Ruminant

Stomach complex con’t

  • Reticulum
  • Omassum
  • Abomasum
    • True glandular stomach
    • Lined with mucous membrane and gastric juice secreted
digestion in the ruminant6
Digestion in the Ruminant
  • Rumen/reticulum and omassum collectively term:

 Forestomachs 

    • Lining of these tissues:
      • Stratified squamous epithelium
        • “layered, scaly” epithelium
      • Not glandular
        • No secretions
digestion in the ruminant7
Digestion in the Ruminant
  • Esophageal groove (reticular groove)
    • Groove which can contract and form tube to bypass rumen/reticulum
    • Empties into omasum
    • Fxn =
      • Allow milk to pass directly to omasum and abomasum
      • Keep milk out of young ruminant’s undeveloped rumen
digestion in the ruminant8
Digestion in the Ruminant
  • Rumen - Anatomy/Function
    • Main fxn = act as site of anaerobic bacterial fermentation
      • Anaerobic microorganisms live and reproduce
      • No oxygen = anaerobic
    • Undeveloped at birth – sterile
    • Partially developed at 4-6 weeks of age
    • 1st place food goes in adult
    • Some nutrients bypass anaerobic fermentation
digestion in the ruminant9
Digestion in the Ruminant
  • Rumen wall covered with papillae
    • Small finger-like projections.
    • Increase surface area.
    • Influence by diet and season.
  • Storage of food
    • Consume large amounts can digest later.
      • Regurgitation, remastication, etc.
digestion in the ruminant10


Digestion in the Ruminant
  • Microorganisms in the rumen digest
    • CHO – cellulose and starch
      • Fermentations produces Volatile Fatty Acids

Fiber (cellulose)

Corn (starch)


digestion in the ruminant11































Digestion in the Ruminant
  • VFA’s
      • Acetate/acetic acid (2 carbons)
      • Propionate/propionic acid (3 carbons)
      • Butyrate/butyric acid (4 carbons)
  • VFA’s absorbed through rumen wall
    • Can supply 50-100% of required energy for ruminant
digestion in the ruminant12
Digestion in the Ruminant
  • Main benefit of microbial fermentation
    • Produce microbial protein as they live and reproduce





MCO protein

C skeleton


  • Utilize urea (non-protein source)
  • Utilize plant/animal protein
digestion in the ruminant13
Digestion in the Ruminant
  • Bacteria pass through rumen with feed to lower G.I. Tract
    • Protein (feed and microbial)
  • Microbial protein contains ~50% CP
    • Excellent protein source
  • Microorganism also synthesize:
    • B vitamins – thus no req’t
    • Vitamin K
  • Microorganism also contain:
    • 1 – 2 % CHO
    • 3% fat – essential FA’s present – no req’t for FA
digestion in the ruminant14
Digestion in the Ruminant
  • Rumen provides favorable environment for microbial growth due to:
    • 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
Digestion in the Ruminant - 2
  • Anatomy – continued
    • Reticulum – Honey Comb
      • Fxn – Site of microbial action & absorption of VFA’s
      • Fxn – Pacemaker for rumen contractions
        • Contractions start in reticulum spread to rumen
        • Mixes rumen contents
digestion in the ruminant 21
Digestion in the Ruminant - 2
  • Anatomy – continued
    • Reticulum – Honey Comb
        • Heavy particles move to bottom, lighter ones float
        • Lighter particles subject to ruminationRumination = regurgitation, remastication, resalivation, reglutition
digestion in the ruminant 22
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 23
Digestion in the Ruminant - 2
  • Small intestine, large intestine
    • Very similar to that for non-ruminant
  • Post Gastric Fermentation
    • Approximately 5-15% of cellulytic digestion can occur in colon and cecum
    • MCO here as well but lost in feces, lose MCO protein
    • VA’s produced and can be absorbed through L.I.
    • Primary function is still water absorption
rumination process1

8 hr

per day

Rumination Process

Define = set of steps that reduce particle size of digesta for passage to lower tract

  • Regurgitation
    • Bolus is moved by reverse contraction of esophagus from rumen to mouth
  • Remastication
    • Reduce particle size
  • Resalivation
    • Buffer
    • Nitrogen recycling
  • Reglutition
  • Process of removing gas from the rumen
    • 50 – 200 liters/day
    • Gases produced : H2 – hydrogen CO2 –carbon dioxide CH4 – methane H2S – hydrogen sulfide




  • Rumen contraction forces gas to the back and then forward
  • Gas forced up esophagus to the trachea
  • Problem = Bloat
    • Primarily caused by inability to eructate
      • Froth
      • Foam
    • Secondarily caused by something anatomically wrong
    • Commonly seen distention of left side
  • Problem = Bloat
    • Primarily caused by inability to eructate
      • Froth
      • Foam
    • Secondarily caused by something anatomically wrong
    • Commonly seen distention of left side
    • Legumes (soluble protein) – primary cause
    • “Barn door left open” – wheat pasture, lush grass
    • Treatment/prevention
      • Trochar
      • Ionphores