Digestion, pastures, welfare Flashcards

Question

How would time and diet affect rumen parameters

Answer 1

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

Answer 2

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

Answer 3

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

Answer 4

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 *

Answer 5

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

Answer 6

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)

Answer 7

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 *

Answer 8

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

Answer 9

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

Answer 10

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

Answer 11

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

Answer 12

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.

Answer 13

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

Answer 14

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

Answer 15

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.

Answer 16

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.

Answer 17

Glucose can be utilised for * oxidative metabolism in tissues * glycogen synthesis and storage in the liver and muscles * pentose phosphate pathway nessary for the production of DNA nad RNA * lipogenesis in the liver and adipose tissue for energy storage as triglycerides in monogastric animals, however, **ruminants do not convert glucose into long chain fatty acids**

Answer 18

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

Answer 19

Glucose use by various tissues The central nervous system, developing foetus and lactating mammary gland have the highest requirements for glucose, so that late lactation and early lactation are critical times for the devlopment of hypoglycaemia in mammals. Hypoglycaemia in late pregnancy and early lactation can also lead to ketoacidosis and loss of the dam and progeny. Glucose use * 20% human CNS, 70% wether CNS * skeletal muscle 10-25%, smooth muscle 10% of glucose * 5% for fat synthesis and turnover * 40-70% of pregnant ewes circulating glucose used by foetus mostly erythocyte oxudation and energy to neural tissue * 60-85% used for lactose synthesis in the lactating mammary gland

Answer 20

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

Answer 21

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

Answer 22

Non associative earning Habituation * wanning of response to repeated stimulus * stimulus dose not result in an event important event over time the overall response diminishes * continuous response would waste energy and time of the animal * eg foraging bird flees first few times a human passes by Sensitization * animals response increases with each time it is exposed to a stimulus * stimulus repeatedly does result in an important event * learning to respond eg vets minor discomfort of vaccination

Answer 23

Associative learning Classical conditioning * Forms an association between a neutral stimulus (not usually affect an animal) and a stimulus that would * eg bell and salivation in dogs Operant conditioning * Forms an association between a behaviour (performed by the animal) and a consequence

Answer 24

Operant conditioning Response can be made more likely reinforced, or less likely punished Reinforcment or punishment can be either positive or negative * positive added and negative removed Examples * R+ a dog sits to get a treat * R- a horse learns to run away after slipping its collar * P+ A cat stops scratching after receiving a smack * P- A dog stops jumping for attention when it is ignored

Answer 25

Motivation = an animals internal state that drives decision making Motivations cause an animal to obtain a resource that is needed This results in two phases of behaviour Appetitive phase * searching for the resource * eg motivation to drink osmoreceptors in the hypothalamus - salty blood leads to thirst - filling of stomach and sensors on lips stop thirst prior to osmolarity of blood restored eg fistula * first is under dishinibition Consummatory phase * Consuming the resource to satisfy the motivation Inability to perfomr the consummatory phase can lead to behavioural issues

Answer 26

Animals welfare status may be indicated by ? * behavioural observation - ethogram * choices and preferneces * work an animal will do to gain a resource * work an animal will do to avoid a painful stimuli * approach avoidance * deviations of normal behaviour * interactions with humans There is no single measure that provides a definitive measure of an animals welfare

Answer 27

Sterotypic behaviour can be defined as behaviours that consist of * morphologically identical movements * that are regularly repeated * have no obvious function, or are unusual in the context of their performance * can occur in prolonged ( days or weeks) conflict or thwarting situations in which their is no chance of escape * indicative of a high level of motivation

Answer 28

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

Answer 29

GIT The primary purpose of the GIT system is to ingest and hydrolyse (or ferment) nutrients into forms that can be absorbed, metabolised and distributed to other tissues; to neutalise toxins and excrete waste. * ingestion * digestion / fermentation - hydrolytic breakdown of large molecules into smaller ones * absorption * metabolism - within enterocytes or by the liver * excretion

Answer 30

Enteric nervous system The gastrointestinal systems own (intrinsic) nervous system that is completely contained within the wall of the gastrointestinal tract * can operate independantly from input of the central nervous system * submucosal and myenteric nerve plexus connecting sensory cells with glandular and muscle cells via interneurons * submucosal plexus and myenteric plexus

Answer 31

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

Answer 32

Short / Long reflex arc of the digestive system **Long reflex arc** * integrate the central nervous system in neuronal signalling * eg central nervous system signals stomach and salivary glands a meal is on its way / increasing saliva production and stomach juices **Short reflex arc** * neuronal signalling occurs entirely within the enteric nervous system * eg stretching of the rectal wall signals to the internal spincter to relax allowing for defecation to occur

Answer 33

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

Answer 34

Cat and dog RER Resting energy requiremnet * energy requirements of a fed animal at rest in a thermoneutral environment. This measure is typically used in determining energy requirements of cats and dogs in care DER Daily energy requirement * Average daily energy expenditure of a cat or dog dependant on life stage, physiological state and activity. It is expressed as a **multiple of RER.** This measure includes all energy expended for maintenance of essential functions as well as growth, activity, gestation and lactation.

Answer 35

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)

Answer 36

A heat increment is the total amount of heat generated from its ingestion, fermenatation/digestion, excretion and the heat genertaed as a result of nutrient metabolism. eg lipid synthesis, glycogenesis, and gluconeogenesis

Answer 37

Energy systems **Net energy** * seperates the energy requirements into their fractional components maintenance (NEm), tissue gain and lactation * mainly referred to as net energy for maintenance and net energy for gain (NEg) * estimates of net energy from feed can reliable and accurately account for the energy directly available to the animal for production and maintenance * used when efficient food practices have a large impact on marginal returns * eg feed lot * complex system to apply in practice **Digestable energy** * easy to estimate in practice * dose not provide consistant and reliable of energy available from feeds for maintenance and production * dose not account for energy lost as combustable gases, heat * apparent **Metabolisable energy** * reliable reflects energy available from a feed available for maintenance and production * simple system to apply * estimates of ME are not fixed but vary with; dry matter consumed, adaption of GIT to feed, size and maturity of animal, balance of nutrients supplied by the total diet * despite this it is usual to use a single value to describe the estimeted ME from afeed using a mature steer etc.

Answer 38

Production affects maintenance ## Footnote As an animals intake of nutrients increases (or decreases) with it level of production. The size and amount of work performed by the animals GIT and accessory digestive organs also increases (or decreases) and thses changes are categorised with maintenance requirements. Note maintenance requirements are not fixed

Answer 39

Different approaches to describing the energy available from a feed Dry matter intake (DMI system) * easy system refers to maximum potential weight of dry matter of adequate digestability * expressed as a percentage of the animals live weight * frequently used in grazing systems Total digestable nutrients (TDN) * indirectly related to the digestable energy available from a feed based on approximate analysis * TDN% = (5.31 \* CP) + (0.421 \*CF) + ( 1.444\* EE) + (0.937 \* NFE) * tends to underpredict the feeding value of concentrae compared to forage * may be used to calculate the potential dry matter intake of a group of livestock Relative feed value (RFV) * A prediction of the nutritional value of a forage to grazing livestock, combines estimated intake ( based on neutal detergent fibre content of a feed) and estimated digestability (based on acid detergent fibre ADF) into a single index Relative forage index * combines preducted intake and digestability, * estimates of forgae intake are based on estimates of forgae intake and digestability based on incubating feedstuff with with rumen microorganisms in a simulated digestion. * more accurate

Answer 40

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.

Answer 41

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)

Answer 42

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

Answer 43

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.

Answer 44

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

Answer 45

Three factors affect dry matter intake * digestability * nutrient balance * availability

Answer 46

Unsaturated fats are healther than saturated fats * membranes that contain a high concentrations of saturated or trans-unsaturated fatty acids require high concentrations of cholesterol to remain fluid * and increase the amounts of VLDL which is associated with poor vascular and heart health.

Answer 47

High linoleic ratio in diet The result would be a diet that is proinflammatory * high alph linoleic may inhibit blood clotting (platelet aggregation) * high deficient in Arachidonic acid - may inhibit blood clotting and reduce the viable number of kittens born

Answer 48

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

Answer 49

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

Digestion, pastures, welfare Flashcards

(104 cards)