Digestion, pastures, welfare Flashcards
What is apparent digestability and how do we calculate it ?
Apparent digestability
Why do we use apparent digestability
- difference between faecal dry matter and ingested dry matter dosen’t accurately describe the digestability of feed
- faecal dry matter contains microbes, digestive enzymes, lipids and minerals which were not obtained fromdigestive feeds
- adjusments are required to obtain the true digestability of feed
Apparent digestability = (DM ingested * DM excreted) / DM ingested * 100
Describe the process of protein denaturisation in the stomach ?
Protein denaturation ?
- Denaturing of a protein occurs through the loss of its complex structure (quarternary, tertiary, and secondary structure to a primary polypeptide chain.
- this occurs as response to PH, heating, strong salt solution or organic solvents
- salty, acidic, environment of the stomach
- Gastric glands secrete pepsinogen which is activated to pepsin. HCL denatures protein and pepsin chops it up (hydrolyses it) into peptides
- Further the straightened peptide structure allows proteases to attach to the polypeptide chain and hydrolyse the peptide bonds.
- remaining digestion with proteases and absorption takes place in the small intestine.
What is hydrolysis ?
Hydrolysis
digestion - the chemical breakdown of a compound due to a reaction with water.
Describe protein denaturisation with the small intestine ?
Protein in the small intestine
Further digestion and absorption of proteins occurs in the small intestine
Large polypeptides - oligopeptides (intestinal lumen) - amino acids, di and tri peptides (brush border of small intestine)
Small intestine lumen
- Pancreatic acinar cells secrete the inactive forms of trypsin (trypsinogen, chymotrypsin, carboxypeptidase)
- brush border enzymes activate trypsinogen to trypsin by cleaving a polypeptide
- which activates the other proteins to oligopeptides
Small intestine brush border
- brush border enzymes aminopeptidase, carboxypeptidae, and dipeptidase which are embedded in the brush border membrane - act to hydrolyse oligopeptides to amino acids and di, tri peptides
- multiple proteases are required for the digestione of protein some in the brush border, others located in the lumen.
- Different proteases target different amino acid sequences
Provide examples of digestable and indigestable carbohydrates ?
Digestable and indigestable carbohydrates
Carbohydrates are classified by the number of sugar units linked together with glycosidic bonds
Digestable
- starch and glycogen
Indigestable
- plant cell wall
- milk oligosaccharides
Reasoning
- starch has an alpha 1-4 glycosidic bond which can be hydrolised in the small intestine hence digestable
- cellulose has a beta 1-4 glycosidic bond which is unbreakable in the small intestine (however can be broken down by microbial enzymes)
- Beta 1-4 glycosidic bonds orientate the glucose subunits up and down, which results in straight chains of glucose units which can form hydrogen bonds with adjacent cellulose chains forming a stable crystalline structure.
- cellulose is a structural carbohydrate as it is used by the plant to support its cell wall to support its weight
Describe the intial digestion of carbohydrates within the mouth and stomach ?
Digestion of carbohydrates
Polysaccharides, oligosaccharides and disaccharides must be hrodrolysed to their component monosaccharides (typically glucose, fructose and galactose) to being absorbed
Mouth (pigs and people, but not cats and dogs)
- salivary glands secrete serous saliva conatining amylase which hydrolyses alpha glycosidic between the glucose subunits of starch
- product = oligosaccharides and maltose
Stomach
- salivary amylase continues to hydrolyse starch until inactivated by HCL of the stomach
- product = oligosaccahrides and maltose
Describe the digestion of Carbohydrates in the small intrerstine ?
Digestion carbohydrates in the small intestine
small intestine lumen
- pancreatic acinar cells secrete pancreatic juice containing amylase which hydrolyses starch and oligosaccharides
- product = mostly maltose, maltotriose, dextrins and some glucose
Brush border lumen of the small intestine
- Brush border enzymes are anchored to the cell membrane
- Maltase - hydrolyses maltose and maltotriose
- Lactase - hydrolyses lactose
- Sucrase, Sucrase/isomaltase, maltase-glucoamylase - able to hydrolyse alpha 1-4 and alpha 1-6 bonds of oligosaccharides
Describe the species differences in the secretion of lactose and sucrose ?
Unique features brush border enzymes
Lactose
- is usually absent in the small intestine of adult domestic animals
- lactose feed to adult domestic monogastric dmestic animals is fermented in the large intestine which result in diarrhoea
Sucrose
- In ruminants sucrose is absent in the small intestine. Sucrose feed to ruminants is fermented in the rumen
- In horses there is sucrose in the small intestine - allows for digestion of large amounts of plant sugars (glucose, fructose) can be ingested when horses consume short pasture grasses
Describe the process of protein, carbohydrates and B group vitamins absorption ?
Protein absorption
Absorption of di, tri peptides, amino acids, sugar monomers (monosaccharides), B group vitamins and bile salts occur in the small intestine.
- monosaccharides, B group vitamins, amino acids mostly takes place in the jejenum but also in the duodenum and ilieum.
- secondary active transport
- fructose = faciliated diffusion
- bile salts and B12 are most absorbed within the jujenum by secondary active transport Na+/K+.
These nutrients diffuse across the interstitual space and into capillaries where they enter the superior mesenteric vein then the hepatic portal vein and then the liver
Describe the digestion of fats and triglycerides ?
Digestion of fat, triglycerides
small intestinal lumen
- triglycerides are insoluble in water and form droplets in aqueous solution
- bile salts and a polar and non - polar component
- absorb onto the surface of the fat droplet undergoes emulsifiction into micelles (fat droplets coated in polar salts)
- emulsification cretaes a high surface area to volume ratio and increases lipase efficiency on triacylglycerols
The action of lipases
- hydrolyses two of the ester bonds joining fatty acids to glycerol
- this produces two free fatty acids and one monoglycerol for each triglyceride
- free fatty acids and monoglycerol diffuse across the enterocyte cell membrane within the brush border
Free fatty acid and monoglycerol are reformed into tricylglycerols within the enterocyte leaving the cell via exocytosis and entering a lacteal.
Describe the intracellular / paracellular route of absorption for minerals ?
Mineral absorption
Intracellular route of absorption
- utilizes active transport mechanisms
- absorption usually total
- small and large intestine
- transporter proteins in the apical membrane and binding proteins in cytosol regulate the quantities absorbed absorbed
- Absorbs Na+, CL-, K+, HCO3 2-, PO4 3- , SO4 -2 and (Ca2+, Mg2+ and Fe2+ at low concentrations)
Paracellular route of absorption Ca2+ and Mg2+
- utilizes a concentration gradient
- ions move along a concentration gradient into the intestinal space
- jejenum and ileum site of absorption
- Claudins - tight gap junction proetins open and close gated pores for regulation of Ca2+ and Mg2+
Once minerals are absorped secretion via the kidneys becomes the primary regulating steps.
Absorption of most minerals is regulated according to the status of the animal, except Na+, CL- and K+
What are claudins, and how do they work ?
Absorption of calcium with low dietary intake ?
Absorption of calcium at low dietary intake
The cellular and plasma concentrations of Ca2+ is highly regulated
- calbindin = binding protein
- Calcitriol vitamin D3 acts to increase the production of both calcium binder and transporter proteins
- increase uptake of Ca2+ across the apical membrane
- Ca2+ is only released from the binding protein when it is positioned to be actively transported out of the enterocyte to diffuse to the capillaries
- calcium involved in neuromuscular and cellular metabolic processes
The presence absence of transporter and binding proteins regulate the uptake and intracellular transport of calcium in response to the action of Calcitriol (vitamin D3) at low dietary intakes of calcium
Describe the tight regulation of ion absorption ?
Absorption of ion ?
- absorption of iron takes place in the duodenum
- tightly controlled via intracellular route as excess iron is toxic, particularly to live paranchymal cells
Process of absorption
Unsaturated
- when iron stores are reduced iron moves across cell membranes into cappillaries where it is bound to unsaturated transferrin, which allows transport of iron to tissues.
Saturated
- When iron stores are saturated, transferrin is saturated and less transferrin is produced by the liver.
- reduced iron Fe2+ crosses the cell membrane, and is bound to apoferritin Fe3+where it migrates to the top of the villus and is sloughed of with the turnover of epithelial cells
Describe the affect of salmonella on digestion and absorption ?
Salmonella
Infection of the mucosa typically results in a loss of epithelial integrity and the leakage of salts, antibodies, fluids into the lumen of the small intestine. Enzymes associated with the brush border are lost + inflammed tissue can not absorb nutrients. The net effect is munutrition, diarrhea and dehydration. A secondary effect maybe systemic acidosis through loss of bicarbonate in feces or diarrhea.
Salmonella
- invades and multiplies in enterocytes and penetrates the lamina proper
- damage to the mucosa results in villus atrophy, malabsorption and inflammatory diarhhrea
- once past the lamina proper the organism can enter systemic circulation
- typhoid fever
Describe the effects of Giardiasis ?
Giardiasis
- causes an increase in permeability of enterocytes
- decreased activity of the intestinal brush border especially lipase and some proteases
- there is a decrease in overall absorptive area of the small intestine leading to impaired absorption of water.
- secretory and osmotic diarrhea
Describe the nutritional strategy of a bovid ?
Bovid nutritional strategy
A ruminant is to eat a small number of large meals of herbage daily
- 30% of day spent grazing
- ingesta reside in the reticular rumen for a long period allowing processing and fermentation with maximal digestion and absorption of nutrients
The physical capacity of the reticulo rumen is large and feed particles can have a long retention time in the GIT (≈50hrs)
- fecal texture moist, small size and shape of physical particles in the matter
Describe the nutritional strategy of an equid ?
Nutritional strategy of an equid
An equid eats a large amount of small meals herbage daily
- 65% of the day spent grazing
- the equid has a shorter retention time for ingesta in the hind gut (around 24 hrs)
- thourough digestion of sugar, protein and fats - digestable matter
- small amount of fermentation of fermentable plant cell wall in the hind gut
- this means the digestability of herbage is lower and faecal output is higher in equids compared to ruminants ingesting the same amount of herbages
- solid fecal matter larger particles within matter
Describe the process of fermentation in ruminants ?
Fermentation in ruminants
Bovids have a much higher reliance on fermentation to meet their needs for energy and metabolic precursers compared to equids
- fermentation in the reticulo-rumen meets 70-80% of the protein and energy requirements of a mature ruminant
- competitive adavntage over equids when there is a small mass of low quality herbage available
- extracts more energy for each unit of herbage consumed
- able to recycle crude protein mostly as urea returning to the rumen from the liver via saliva
Herbage dry matter intake by a ruminant will decrease as herbage quality increases
Describe the process of fermentation in the equid compare this to other species ?
Fermentation in the equid
Absorption of fermentation acids in the hindgut can meet 30-40% of requirements
- fermentation can not meet protein requirements, as there is no digestion and absorption of protein in the hindgut where microbial biomass is produced
- competitive adavantage over ruminants when there is a large mass of low quality herbage - can maintain a high rate of digestable and fermentable nutrients as they are able to increase their daily dry matter intake
Herbage dry matter intake by an equid can increase as herbage quality decreases.
What is the process fermentation ?
The process of fermentation
Is the extraction of energy and metabolic precursors (metabolites) from organic matter (mostly carbohydrates and proteins) by microorganisms in the absence of oxygen with the production of microbial biomass, fermentation acids, gases and heat.
Produces
- mostly produces volatile fatty acids, acetate, propionate and butyrate as well as microbial biomass
- gases CO2, CH4, H2
- heat
The process of fermentation requires
- carbohydrate source
- ammonia and amino acids
- microorganisms
- PH 5.5-7 (healthy)
- motility - mixing and moving
- rumination - eructation
Why is fermentation in the horse less efficient when compared to the ruminant ?
Rumination in the horse is less efficient because
- larger particle size
- shorter residence time of particles
- reduced PH buffering
- low availability of nitrogen compounds to support fermentation
- reduced surface area to volume ratio
Describe the species variation in hindgut anatomy ?
What are the products of fermentation ?
How would time and diet affect rumen parameters
Both time and diet affects rumen parameters how?
Note a grain based diet = high starch
Time - after a meal
- increase concentrations of volatile fatty acids
- increase ammonia N
- PH decreases shortly after a meal in rumen fluid
Diet
- grain based diet high in starch
- more total VFAs
- rate of proponate production is higher compared acetate changing the fermentation pattern
Which diet (high fibre or high starch) would support the greatest rates of productivity ?
A high starch diet eg grain
- grain based diets produce more microbial protein and volatile fatty acids per unit dry matter consumed by the animal
- animals are able to consume more of these diets compared with forage based diets
- hence feedlots base their feeds of cereal grains
When is rumen PH at its lowest, and concentrations of VFAs, lactate and ammonia at its highest ?
- 2-3 hours post feeding morning when fermentation is most active
Describe primary fermentation and seconadry fermentation ?
Primary fermentation
Primary rumen bacteria (classified according to the nutrients they break down) ferment dietary nutrients such as
- plant fibre = fibrolytic = beta glycosidic bonds cellulose
- starch = amyolytic = alpha glycosidic bonds starch sugars
- protein = proteolytic
Secondary bacteria utilize the end products of primary fertilization
- methanogens produce methane from formate CO2, and H2
- Lactate/ succinate fermenters produce propionate
All these biochemical processes produce ATP or “free” energy to support metabolic processes
Disscuss the three primary volatile fatty acids produced in the ruman, caecum and colon of hindgut fermenters ?
Fermentation produces
Three volatile fatty acids
- Acetic acid/ acetate - ketogenic/lipogenic
- Proprionic acid/ propionate - glucogenic
- butyric acid / butyrate - ketogenic/lipogenic
and small amounts of
- Proprionate, lactate and valerate are glucogenic so the bulk of glucose for ruminants on pasture based diets is derived from these volatile fatty acids
- L-lactate is either converted to acetate or propionate or is directly absorbed from the reticulo rumen hindgut
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What builds up with unhealthy rumen fermentation patterns at low rumen fluid PH ?
D- lactic acid
Is the form of lactate associated with grain poisoning lactic acidosis.
- formed by the fermentation of starch by streptococcus bovis
- D- lactate is porrly absorbed and its concentration can build up in the reticulo-rumen hindgut resulting in lactic acidosis
- slowly it is metabolised by lactate fermenting microorganisms to L-lactate, acetate and propionate; which are readily absorbed across the rumen wall
- lactate is an organic acid, but is not categorised as a volatile fatty acid
Describe absorption from the reticulo rumen and large interstine ?
Absorption in the reticulo rumen and large intestine
- absorbs VFA, minerals, water ammonia
- only undissolved protonated form of VFA will be absorbed
- rate of VFA absorption increases as PH drops
- VFA 70-85% absorbed reticulo-rumen - 10-15% large intestine
- acetate enters the circulation through the portal vein unchaneged immediately available for metaboloic processes
- butyrate is mostly converted to B-OH in epithelial cells and enters the circulation as ketone bodies
- propionate is mostly converted to glucose in the liver
- methane readily absorbed - into the lipid bilayer of epithelial cells
- methane excreted as expiration (not burps or farts)
Why is it important for the rumen to have well vascularised papillae, and what factors promote the formation of these papillae ?
Why is the rumen well vascularised ?
- increases rate of VFA absorption
- which increases the capacity of the rumen to fermentic matter
- which potentially increases dry matter intake and productivity
What factors promote the formation of these papillae
- sufficient roughage in the diet (scratch factor)
- stimulates their growth and maintenance of normal rumen fluid PH and fermentation pattern
*
Describe the metabolism of acetate ?
Acetate
Acetate is the most abundant metabolite derived from fermentation in foregut and hind gut fermenters
- ketogenic and lipogenic
- 2 carbon acid
- not glucogenic
- it is the primary carbon source to meet energy requirements and for lipogenesis in herbivores
Describe the metabolism of propionate and butyrate ?
Describe the metabolism of propionate and butyrate
Propionate
- primary source of glucose for all ruminants
- 3 carbon acid glutogenic
Butyrate
- important source of energy for GIT processes as well as for fat synthesis
- 4 carbon acid ketogenic and lipogenic
Why will a deficiency of CO in the diet of ruminants result in ill thrift, but not equids ?
CO deficiency in ruminants and equids
- Because cobalt deficiency results in a deficiency of vitamin B12 for microorganisms of ruminants and therefore the ruminant animal
- B12 is is a cofactor in methyl transfer reactions
- A deficiency disrupts metabolic processes that utilise methyl transfer including amino acid and fatty acid metabolism
- conversion proprionate to glucose in ruminants leading to ill thrift
Equids
- equids typically derive preformed B12 from the diet directly
- a deficiency in of cobalt CO dose not affect their supply of this vitamin
Comparison of motility in the rumen-reticulum of the steer and horse hindgut?
Gut motility
Horse
- mixing via segmentation (shuttle contractions)
- peristalsis and antiperistalsis occuring concurrently with mass movements fill and empty caecum colon
- significant sorting of particles where the gut narrows (red arrows)
- no mechanical diminution of particles
Ruminant
- motility includes mixing, sorting and mechanical diminuation by rechewing through rumination
- nutrient rich fluids may be directed straight to the omasum as to not undergo fermentation
- rumination uses antiperistalsis and perstalsis in the reticulo rumen as well as sequenced contractions in the reticulo rumen
Why is good dentition and time a horse spends feed so important to gastrointestinal tract function when compared to a ruminant ?
dentition and time to chew
- the horse has a single opportunity to grind ingested feed into small particles with a large surface area
- where as the ruminant can process feed as many times as is required to make the particles small enough to leave the rumen.
Describe the normal physiological reticulo-rumen parameters, and what mechanisms maintain these parameters ?
Normal physiological reticulo-rumen parameters
- anearobic - scaveneged quickly by some species of bacteria
- PH 5.5 -6.5, carbonic acid, bicarbonate and buffers in saliva
- osmotic pressure similar to blood
- temperature 39 degrees one above core body tempeature
- microbial population - protozoa, bacteria and fungi
- ruminal contractions - long forage in the diet stimulates contractions. 4-8 strong contractions every 5 mins when feed
Maintenance of these parameters eg rumen fluid PH 5.5 - 6.5
- high rtae of salivary flow well buffered due to high concentrations of bicarbonate and phosphate
- high rate of absorption organic acids comapred to the absorption of the conjugate organic salts across the rumen wall
Describe abnormal hindgut chemical parameters for horses in heavy work ?
Abnormal parameters of horses in heavy work fed concentrates.
Idications theres a problem with digestion
- high content of starch
- high concentration of D lactate due to rapid fermentation of starch making it through the small intestine to the large intestine
- low PH indicating high amounts of starch in faeces
- mucous on faeces, diarrhea and colic
Normal faeces parameters
- mildly acidic to neutral PH
- low dry matter high moisture content (firm moist faeces)
- low strach and nitrogen contents
- high concentration of acetate compared to propionate and butyrate
- low concentration of L and D lactate
Overview Unit 2 lecture 3
Summary of proteins, fats and carbohydrtaes
Summary of vitamins, minerals and pathogens ?
Provide a summary of metabolised nutrients ?
What are nutrient reserves ?
Nutrient reserves
a supply of nutrient not immediately utilised but availble if required
- when ATP, glucose levels are high in plasma the body is stimulated to produce glycogen, creatine phosphate and triglycerides
- lipids are stored as triglycerides in adipocytes with no storage of non esterfied fatty acids or ketones
- Ca and P is not stored in bone but may be mobilised if required - muscle function
- protein is not stored in muscle but may be mobilised if required to provide amino acids for critical protein dependant processes such as glucogenesis.
Discuss water metabolism ?
Water metabolism
metabolic water assumes oxidation of 100g protein, 600g carbohydrate and 100g fat
- water is availble to animals through ingested water (water in food and drinking water), and from metabolic wtaer
- ingested water supplies the majority of the animals needs
- metabolic water is produced by oxidation of metabolites 42 grams of water per 100 grams of protein, 60 grams water per 100g carbohydrate and 100 grams of water per 100 grams of fat oxidised.
- fat thee fore produces the most water and energy per unit dry matter
Water balance in most animals is typically regulated between the amount ingested and excreted as urine.
How does insulin and glucagon maintain plasma glucose concentrations ?
Maintenance of plasma glucose concentrations?
Insulin
- anabolic
- increases triglyceride synthesis
- increase glucose uptake to many cells
- decreases lipolysis
- increase amino acid uptake in many cells
- reduces the concentration of glucose, FFA and amino acids in plasma
- GLUT4 insulin dependant directs glucose to glycogen synthesis
Glucagon
- catabolic
- stimulates liver glycogenolysis
- stimulates hormone sensitive lipase
- increases the concentration of glucose and FFA in plasma
Describe the metabolism of glucose after a feed in pigs ?
Recover glucose metabolism in the post absorptive pig ?
Describe the composition of muscle throughout the digestive tract ?
Summary post absorptive use of glucose ?
What is the difference between an innate and learned behaviour ?
Innate/learned behaviour
Innate
- dose not require learning
- fully functional first time performed
- nest building/ suckling
Learnt behaviour
- This is the modification of behaviour as a result of experience
- allows for adjustment
- non associative
- associative
- insight reasoning
- imprinting
What are the interstitual cells of Cajal ?
The interstitual cells of Cajal
Are pacemaker cells located between the circular and longitudinal muscle layers along the length of the gastrointestinal tract
- regulate the onset of the slow wave peristaltic activity in the GIT tract
- signals from the GIT tract and CNS can increase the intensity and timming of peristaltic waves in the GIT, to bring about contractions resulting in motility.
- below that required to produce an action potential
- spontaneously produce a slow wave electrical
What are sphincters and where are they located within the gastrointestinal tract ?
Sphincters
Sphincters control the movement of material from one part of the GIT to another, and usually prevent the backward movement of material. This ensures that sections of the GIT tract with seperate chemistry and function are seperated into compartments.
- upper oesophageal sphincter
- lower oesophageal sphincter’pyloric sphincter
- ileocaecal valve
- anal sphincter
Describe the general structure of the wall of the small intestine ?
General structure of the intestinal tract
Mucosal layer
- epithelium columnar epithelial cells
- laminar propar connective tissue - contains (blood + lymph vessel) bruuners glands in the duodenum and peyers patches in the jujenum
- muscularis mucosa - smooth muscle
Submucosa
- connective tissue contains tubular glands, blood and lymph vessels
- submucosal plexus - nerve cells that provide neural input into glandular tissue
Muscularis Externa
- consist of an inner circular layer, and an outer longitudinal layer of muscle fibres
- contraction of circular muscle causes the lumen to narrow
- contraction of longitudinal muscle causes the lumen to expand
- myenteric plexus - nerve cells that communicate with the submucosal plexus
Serosa
- thin layer of connective tissue covered by a single layer of cuboidal epithelial cells called visceral peritoneum
Why would we want to express the nutrient content of a feed or feed ingrediant based on its dry matter content?
Base nutrient content upon dry matter content ?
- moisture content is highly variable
- moisture dilutes the nutrient content or energy content of that feed or feed ingredient
How do we measure metabolic energy, how do you interconvert calories and joules ?
Measuring metabolic energy
- 1 cal = 4.18 joules
- 1 joule (J) = 0.24 calories
- 1000,000 jouls = 1000KJ
- Production animal nutrition in Australia, UK and Europe use SI unit of the joule (J)
What is Gross energy GE, apparent digestable energy (DE), metalisable energy (ME) and net energy (NE) ?
Categories applied to defining nutrient and metabolisable energy requirements of animals ?
Recover the summary of Lecture one unit three ?
What are digestable carbohydrates ?
Digestable carbohydrates
Amylose how dose its structure vary
- linear only alpha 1-4 glycosidic bonds
- glycogen and amylopectin found in animals have alpha 1-6 glycosidic bonds, which may also be broken down by enzymes in the small intestine.
What is an undigestable carbohydrate ?
Undigestable carbohydrate
- Carbohydrate that is not digested and absorbed in the small intrstine is termed fibre
- energy from fibre is available to animals using fermentation
- fibre is not easy to define, highly chemically diverse
Soluble fibre = soluble when boiled in water (pectin from fruit, oligosaccharides from milk etc)
Insoluble fibre = is not soluble when boiled in water (cellulose, hemicellulose)
Identify the key plant cell wall fibre categories ?
Define neutral detergent fibre, and how do we calculate the NDF ?
Neutral detergent fibre
It is all the structural components of a plant except the glue like pectins
- cell wall and vascular bundles of cellulose, hemicellulose and lignins
- can be used a s predictor of maximum of dry matter intake (KG DM/day) as it is directly related to its capacity to fill the rumen to its dry matter capacity
- NDF increases as forages mature
Calculate
- boil with neutral detergent fractions to seperate soluble cell contents and pectin
- NDF than boiled in acid PH detergent to seperate dissolve hemicellulose, cellulose and lignin as the remaining solid component is known as the ADF (acid detergent fibre)
- note forgaes are typically low in pectin so this will not usually affect the calculation
Provide a summary of carbohydrates unit 3 ?
What is an essential amino acid, conditionally essential amino acid and dispensable amino acid ?
What is an amino acid profile, and how can this be used to meet an animals needs ?
Amino acid profile
- cereal grains have a low lysine content relative to lysine in animal tissue
- beans, pulses have a low methionine content relative to methione in animals tissues
A complete food ration for a monogastric animal will usually use a combinatin of cereal grains and beans, to provide a balanced amount of lysine and methione and other essential amino acids.
The combination of sweet corn (maize) with beans forms the basis of many dishes to meet the essential needs of amino acids.
Provide a definition of crude proetin, true protein, non proetin nitrogen, metalisable proetin, rumen degradable protein, undegradable dietary protein ?
Provide a summary of protein utilisation lecture three unit three ?
What is a tiller, culm, rhizome and stolon ?
Describe the quality of pasture as affected by maturity ?
Describe phase one to four of plant growth ?
Tropical grass phases
- Phase one = early rapid growth
- Phase two = begining to grow stem, mostly green
- Phase three = Flowering and seed set, 10-30% green
- Phase four = senescence no growth no green
Describe pasture productivity through the four phases of pasture growth ?
What factors affect dry matter intake ?
Three factors affect dry matter intake
- digestability
- nutrient balance
- availability
Describe condition A and B of land condition ?
Describe C and D condition of the ABCD land condition framework ?
Identify three essential fatty acids ?
Describe linoleic acid and its benefits for the body ?
Describe the summary of fats unit three ?
Describe ash and mineral elements in foods ?
Define a macromineral and micromineral ?
Macromineral and micromineral
Macromineral
- Ca, P, MG, S, Na, K and CL
- which are needed in g/day amounts and play a structural or functional role
- bones teeth, energy exchange (ATP), electrolytes, membrane potentials
Microminerals
- B, CO, Cr
- which are needed in ♦g/day (small amounts), and usually participate in chemical reactions or have a metabolic signalling role
Identify vitamins and their categories ?
Overview of vitamins and mineral summary ?
Disruption of key metabolic processes via a loss of minerals and vitamins ?
Describe the role of copper in livestock and signs of deficiency ?
Copper
Signs of deficiency
- lambs uncoordinated gate + increased incidence of fractures
- cattle loss of pigments, infertility, lameness sudden heart failure
- prevention includes the use of copper oxide needles/ wire delivered in gelatine capsules into the rumen
Copper
- cofactor electron transport chain
- production of myelin
- production of progesterone
- production of melanins
Describe the role of selenium in livestock production ?
Describe the role of vitamin A in animal production
Describe the role of vitamin B1 in production animals ?
