Exam 1 Flashcards
What defines a ruminant
Has a rumen- pregastric fermentation (pecorans) started off with headgear, multichambered stomach , mammals, ungulates, obligate herbivores
Abomasum
Gastric secretions
Cardia region
Does not secrete gastric juices
Cattle stomach size
200 Liters- have to develop it
How big is the stomach compared to the cow
Large compared to their body size
Peristaltic contraction
Occurs in tubular structures, can move in the rear towards the mouth and vice versa
Advantages of having a rumen GIT
Herbivores, makes undigestible things digestible, nutrient absorption, avoid predators
Crepuscular behavior
Active when the sun is coming up and going down
End products of fermentation
VFA’s, microbial crude protein
Reticulum
Honeycomb shape, reticular paracarditis (hardware disease)- can pierce the heart and inflames the sac around it- encases and traps materials to protect the GIT tract, site of pregastric fermentation
What is the name of the rumen and reticulum combined
Reticulorume
Reticular groove
Formed by muscular folds of the reticulum
Rumen
Primary site of fermentation, has papillae (increases surface area)
What percentage of nutrients are absorbed in the rumen
50-100% required for maintenance
Omasum
Latest developing compartment, most variable, acts as a sieve, some absorption of nutrients, lots of water absorption, influential in regulating fluid passage from the rumen
Abomasum
Gastric secretions, only compartment that produces gastric secretions, HCL, pepsin, has sphincter that regulates digestive flow
Symbiosis and the ruminant GIT- ruminants are most successful symbiote
Bacteria- ml 1x10 to the 15 , 12 species of protozoa- defaunated (no protozoa), fungi- 100,000 cell/mL
Rate of passage
Total average retention time, influences levels of intake by the physiological characteristics of feed, related to ruminal volume, chemical characteristics of feed
Rate of fermentation and influences
How quikly something can be broken down, diversity of microbes, intrinsic characteristics of feed
Rumen size is a function of what
A linear factor of body weight
Allometric scaling equation
Used to view rumen size as a function of BW, body size is linearly equated to the size of the rumen
Factors that influence fermentation products
Microbial community, residence time (related to ruminal volume), rate of fermentation
Other end products of fermentation
Methane CH3, 25X more potent at trapping solar radiation vs CO2, acetate, butyrate
Differnet grazing strategies- account for differnet rumen sizes
Browser, grazer, intermediate feeders
Browser
Small ruminants, leaves, nuts, fruits- easy to break down, detoxification, can break down carbs
Grazer
less selective, leaves, stem/stalk- breakdown of structural carbohydrates
Intermediate feeder- sheep
Some browse + leaves/stalks and stems
6 nutrients
Carbs, fats, protein, vitamins, minerals, water
Composition of gain
Protein decreases as an animal matures while fat increases (has 2.25 x cal)
Energy
Abstraaction that is defined as the ability to do work
The calorie
1,000 calories= 1kcal=1Cal, 1 Mcal=1,000 kcal= 1,000,000 cal
Heiarchy of nutrient use
Maintenace, development (maintenance of the uterus), growth, lactation, reproduction (obtaining a new pregnancy), fattening
Metabolic priority
CNS, Immunity, Reproduction, Lactation, adipose, muscle
The net energy system
Gross energy (heat of combustion), feces energy, digestible energy, gaseous energy(methane), urine energy, metabolizable energy, heat increment, net energy (used for physiological function)
Totally digestible nutrients
Sum of available energy in feed, a percentage
How to calculate TDN
Digestible carbs+ digestible protein + 2.25 x digestible fat
What is wrong with TDN
Underestimation of energy in concentrates
Carb facts- carbs are not required
major form of energy storage in plants, CHO, starches, cellulose, sugar
Functions of carbs
Source of energy and heat, building blocks for other nutrients, framework for RNA + DNA, animal body converts to fat for storage energy
Monosaccharides
6 carbon sugars- glucose, galactose, fructose, manose-
What do glucose and galactose do
Make lactose
Glycosidic bonds
used to form disaccharides, oligosaccharides, and polysaccharides
Alpha and beta bonds
Starch and cellulose
Disaccharides= 2
Sucrose, lactose, maltose (alpha linkage), cellobiose (beta linkage)
Oligosaccharides= 3-12
Readily hydrolyzed and digested- raffinose, verbacose- poorly digested by monogastric animals, cannot be enzymatically digested
Why add oligosaccharides to the diet?
Fiber like, improve gut health
Polysaccharides > 12 sugars
Starch, Amylose (900-3000, linear), Amylopectin (10,000-500,000, branched)
Forms of starch
Amylose(minimally branched plant starch), amylopectin (branched plant starch), glycogen (branched animal starch)
Cereal grains
Corn, oats, barley, wheat
Cellulose
Chain of glucose, 30% of fibrous plants, digested by microbes, lactase
What is the major energy source in forages
Cellulose
Heteropolysaccharides
Hemicellulose- easily digestible, associated with lignin, pectins- in plant cell walls
Lignin
Most signifigant factor limiting availability of plant cell wall to herbivores and microbes, non carbohydrate, increases with plant maturity, plant rigidity
How important are CHO’s to ruminants
50-80% of forages and grains are CHO’s, VFA’s from CHO fermentation can provide up to all of the energy needed
Types of VFA’s
Acetate (50% of rumen proportion by mass), propionate (10-40%), butyrate (2-7%), valerate, caproate
Where can aerobic organisms derive energy from
VFA’s- they are not fully oxidized (energy cost is considered small)
Ruminal VFA absorption
Reticulo-rumen absorbs >75% of VFA, papillae enhance absorption
Typical ruminant diets
Forage based (cow calf/stocker) grain based (dairy, feedlot)
Cutin
Waxy material, indigestible
What is acetate used for
Lipid synthesis, subcutaneous fat, metabolized first (liver)
What is propionate used for
Glucose synthesis, intramuscular fat and lactose production
What is butyrate used for
Epithelial fuel source, derived from fermentation of branched amino acids
Why do we want more propionate production
Increase circulating glucose, insulin, decrease methane production
Grain:Forage ratio
Increase rapidly fermentable carbohydrate, can reduce rumination, associated with more acid production and lower pH (ruminal acidosis)
Feed processing
Increases rates of digestion-> greater propionate digestion (grinding, flaking)
Drugs and chemicals
Ionophores (increase propionate production, ruminal fermentation, feeding frequency) Buffers (increase acid needed to lower pH, ruminal liquid dilution rate)
Lactic acidosis
abscessed ilver, coma, death, poor feed intake, reuced growth, founder
Post ruminal starch digestion
Limited compared to ruminal fermentation - can provide about 42% more energy than ruminal fermentation
Why is postruminal starch digestion limited
pancreatic amylase production BBM enzyme production, fiber is not digested in the small intestine
Ruminal pH
6.46, physically effective NDF- particle size that is greater than or equal to 1.2mm
Associative effects
Concentrate to forage ratio can have positive or negative associative effects
What is protein
An amino acid- 20 of them used in protein- alpha amino acids
What is protein used for
protein synthesis- principally feed protein for greater diet
What are excess amino acids- multiple stave hypothesis
Amount of protein that can be synthesized depends on the first limiting AA
What happens to excess amino acids
Deaminates to NH3 and excretes as urea in urine- C skeleton can be oxidized for ATP production or synthesis of glucose via glucogenesis
Amino acids deamination
Glutomate, oxaloacetate, ketoglutarate, aspartate
Crude protein system
6.25 X % nitrogen - CP assumes all proteins contain 16% nitrogen
Metabolizable protein
Protein that can be metabolized or is available to the body for protein synthesis
What does crude protein consist of
Non protein nitrogen (contributes ruminal degradable protein) and true protein (ruminally undegradable protein)
What flows out of the rumen- nitrogenous protein that can be digested
Ruminally undegradable protein and Microbial Crude Protein= metabalizable protein
Protein needs of ruminants- microbial growth can be limited when there is a limit of protein and energy
a lot of microbes even when protein limits fermentation ruminants typically absorb adequate protein (protein in ruminal microbes)
Organs important for degradation
Kidneys, salivary glands, skeletal muscle, liver- liver detoxify and creates urea (urea recycling)
What is TDNI closely correlated to
Truly fermentable organic matter
What things influence rate of disappearance - first order kinetic model
Intrinsic factors in feed, processing factors, particle size, pH of the rumen
Net protein
Teue protein from the diet that are used for protein synthesis
Biological value
Net protein/ metabolizable protein x 100
Why are ruminants so inefficent at capturing AA from diet
Limiting AA
What limits protein use by livestock
Body needs the right building blocks, if one is missing the protien cannot be made
Most effienet way to decrease nitrogen excretion
Use crystilian amino acids that have been purified by industrial methods
What should supplemental amino acids be able to avoid
Diet conditions, mastication, rumen fermentation, should be absorbable
Essential amino acids (limit physiological processes)
AA not synthesized in the body in adequate amounts to support protein synthesis
Functional amino acids (limit skeletal growth)
AA not synthesized in adequate amounts to support important physiological processes
What is milk protein most limited by
Lysine and methionine
Why dont we know about AA limits needed for growth?
We more frequently observe limits related to energy
Types of water loss
urine (7-9% DM), feces (15-19% DM), sweat (thermoregulation), OVER 50 is through respiration
Water requirements
Express water as a function of body weight
Factors that influence water intake
Temperature, availablity, dry matter intake (intake lowers with reduced DMI), stages of production (lactation), water quality
Water is what
Most esential nutrient- need for growth, reproduction, lactation
Squamous cells
have no direction
Columnar cells
have direction
How much more influential is DMI than temperature
3.5 times more influential
Finishing cattle
thermoneutral zone is 40-70 degress fairenheit-> no energetic expenditure
water sources
nautral water, grass, snow (8 inches) ,TMR, waterers
Waterers
cattle need 1 inch per head of linear trough space-> heat stressed cattle need 2-3 inches per head
Toxic compounds
heavy metals, toxic minerals
Role of vitamins and minerals
Are the least important nutrients- make people money- co-factors in enzymes
What are vitamins
Called vital-amines- essentials ones are fat or lipid soluble
Vitamin A (night vision)
Retinol. maintenance (47 IU) growth (60 IU) reproduction (84IU)
Vitamin D- calcium absorption
Cholecalciferol- beef (5.7 IU) Dairy (30 IU)
Vitamin E- immune response
alpha- tocopherol, can increase amount in times of stress
Vitamin K- blood clotting
Dicoumarul (rat poison), menaquinones, phylloquinones (green vegetables)
water soluble vitamins- not functionally required
Energy metabolism- Biotin, choline, B12, riboflavin
Calcium- overabundance can cause milk fever
Most abundant mineral in the body- membrane permeability, muscle contraction, nerve impulses, hormones, enzymes
Dietary cation anion difference
Dairy rations for dry cows
Phosphorus- found in bone
Macro-CA:P, energy, DNA,RNA, lipid membranes, don’t want an overabundance
Magnesium (macro)
Important for energy metabolism- grass tetany
Potassium
Important to muscular contraction and nerve impulses - high conentrations can cause grass tetany
Sodium and Chlorine- MACRO
Na is the major cation in the body, CL is the anion, nutrient transport, enzyme activity (facilitated, passive diffusion)- want sodium concentration
Sulfur-MACRO
Microbial efficency- important for methionine and cystine, thiamine and biotin- hydrogen sulfide Brainer/header (PEM)- interactive with diet fiber level (8%)
Chromium-MICRO
Sensetizes insulin responses Glucose tolerance factor
Cobalt-MICRO
Component of B12, fat metabolism, if deficient- poor appetite
Copper- MICRO
Important for the function of metalloenzymes in vitro
Iodine- MICRO
Essential for thyroid hormones
Iron- MICRO
Important for myoglobin and hemoglobin- can become anemic without it
Manganese- MICRO
Glucogenesis, urea cycling- if deficient inadequate skeletal growth, reduced reproductive success
Molybdenum- MICRO
Xanthine and sulfite oxidase
Selenium- MICRO
IMportant in glutathionine peroxidase- reduced immune response if deficient
Selenosis- overabundance of selenium (over 5mg/kg)
Lamness, anorexia, blind staggers, astragalus and stanleya plants
Zinc- MICRO
Important in RNA polymerase, alcohol dehydrogenase- if deficent, alopecia, decreased testicular growth
Why ruminate
Avoid predation, convert poor quality forages to high quality energy and meat/milk/wool products
Rumen digestion site
Digests structural and non structural carbohydrates, protein, makes VFA’s, methane, Co2, Branch chain VFA’s, ammonia
Small intestine digestion site
Digests lipids, proteins, non structural carbs, makes fatty acids, monosaccharides, di and tri peptides, AA
Large intestine digestion site
Digests structural carbs, non structural carbs, protein, makes VFA’s, methane, Co2, VFA, ammonia
Digestion reaction theory
Reaction rate, digesta retention time, reactor volume, cone reactants
rentention time equation
1/passage rate, passage rate is reactor volume/ digesta flow rate
Ruminal development
Rumen is not functional in neonates- newborn calves have an esophageal groove (milk bypasses rumen)- transition at 3-12 weeks of age- over 12 weeks is a functional rumen
What has to occur to develop a functional rumen
Change in compartment size, develop papillae, microbial inoculation
change in compartment size
Abomasum is largest at birth, dietary bulk and age contribute to rumen size
Develop papillae
Little impact on age, dietary bulk has little impact, fermentative end products stimulate papillary growth- butyrate
Microbial inoculation
Little amounts of microbiota present at birth, bacteria are transferred from mother+soil, protozoa are transferred from mother and herd mates
Pregastric fermentation
Ruminants spend 8-10 hours daily ruminating, energy requirment depends on forage quality
Rumination layers
Gas cap, mat layer, liquor layer
Rumination steps
Regurgitation, resalivation, remastication, redeglutition
Eructation- helps maintain homeostasis
Fermentation gases expelled through eructation and respiration (CO2 and methane) more rumination=more belching
Value of predicting DMI
Make diets that meet nutrient needs, improved marketing decisions, primary component of performance
Control of intake in ruminants- all ruminants eat to a constant energy endpoint when not limited by physical fill
Chemostatic= energy content along with other nutrient signals that contribute to hunger and satiety
Physical fill= available volume of the GIT (rumen)
Chemostatic regulation of intake
Regulated by the brain, hormones, adipocytes- the adipocytes secrete leptin and abomasum secretes guralin (leptin has a - response while guralin has a + response on food intake)
Role of insulin in intake regulation
Blocks leptin- regulates blood sugar levels- pancreas keeps making insulin and adipocytes become less insulin as their numbers increase which suppresses leptin and causes hunger
Chemostatic drivers
Hormone, plasma metabolite, metestatic fuel, adaptive neural response?
Physical fill drivers
Distension of the reticulorumen, digesta flow rate, gut motility, hypertenicity of ruminal contents
Goal for feeding ruminants
We want ruminants to eat small frequent meals
Sensory innervation on the leptin side
efferent nervous response, paracrine action
What does hepatic oxidation do
Regulates hepatocytes- important for meal intake
Hepatic oxidation theory
Regulates momentary intake ,optimizes fuel combusted and oxygen consumed, minute to minute
HOT process
Increases in ATP concentration increases in more sodium adn potassium pumps and AMPK decreases- lowers hepatocyte membrane voltage- decreases gap junctions and release of molecules- decreases firing of the vegas nerve- lowers activation of the NTS- inhibits hypothalamic feeding centers
How do ruminants and non ruminants differ
Different metabolic fuels- rely on propionate, delayed pattern of fuel absorption- rate of fermentation, passage
How proprionate affects satiety
Factors increasing proprionate affecting include feed intake and increased CHO ruminal digestion
What happens when proprionate increases
Gluconeogenesis increases and oxidation increases- increased glucose demand causes more gluconeogenesis, oxidation causes less satiety- less feed intake
What components in the equation can we we predict DMI off of
Size of the animal and metabolic body weight, net energy for maintenace requirement, feed maintenance energy
