What 5 things affect the productivity of animals?
Genetic factorsFeeding - DietEnvironmentManagementDisease
What acts as a buffer for rumen pH?
Saliva - produced by chewing and ruminating
What is needed in a ruminant diet?
Fibre - cut 2-4cm
What is essential for cows when chewing?
Comfort - most chewing done when lying down
What three things are required in a cow diet?
EnergyProteinMinerals
How much trough space should be allowed per cow?
At least 60cm
How is the amount cows are actually eating measured?
Dry Matter basis - must know content of all feeds in the diet
How can the dry matter intake for cows be calculated?
(0.025*body weight)+(0.1*milk yield)
How can silage be spoiled?
Anaerobic - air enters causing secondary fermentation and moulds can produce mycotoxins
What are some problems that should be looked for when assessing dairy cow feeding?
Insufficient feeding spaceRough edges of troughs, rails etc.Extremes of hot, cold, rain, light etc.Slippery floorsSelf feeding from silage faceVery tight packed silageElectric fences
What can clover rich pastures cause in cows?
Bloat - magnesium deficiency
What can be fed before turning out to grass each day to supplement grazing?
Buffer feed - silage, hay or TMR to supplement grass to prevent over eating of hungry cows
How should you observe cow comfort?
Undisturbed in straw yards or cubicles
What percent of cows should be lying and ruminating?
60%
What percent of cows should be lying down 1 hour before feeding?
85%
What would cause milk fat to drop significantly?
If concentrates:forage ratio is greater than 60:40
What can spring grass be low in?
Fibre
What percent should milk fat be at?
4.20%
What may low bulk milk fat indicate?
SARA
What percent should milk protein be?
3.40%
When does milk protein drop?
After period of inadequate energy intake
What should be done to investigate feed?
Look at itSmell itHandle itAsk about it (more than one person)
What are the 5 scoring levels for dung?
1 - loose and watery2 - custard and splatters far3 - ideal - slow hand clap that doesn’t stick to boots4 - thick and heavy forming a stack that sticks to boots5 - stiff dung where boot leaves impression
What is the critical time to check dry cows?
6 weeks either side of calving - poor DMI will lead to metabolic disease, poor milk production and poor fertility
What should remain constant in the dry cow?
Body condition score - dry off in the same condition that the cow should calve at
What make fatty liver and other metabolic problems more likely in dry cows?
Trying to lose weight causing excessive fat mobilisation
Describe assessing the metabolic profile in dairy cows
Planned regular blood tests that look at a number of metabolitesNeeds to be done on a regular, planned basisSample about 4 times a year at crucial times
Which cows should not be included in the metabolic profiling of cows?
Sick, unhealthy or poor production cows
What are some common errors with sampling cows for metabolic profiles?
Cows sampled calved more than 20 daysFailure to include some lactation 1 cows in each groupSampling immediately after a major management changeIncluding problem or poor cows
What is used to measure feed intake of production animals?
Wet weight or dry matter per unit of metabolic weight
Why is it impotant to measure feed intake of production animals?
Maximise intake for productionOptimise intake for economicsBalance intake and expenditure for weight controlReduce or minimise intake for weight lossAlso a guide to health/behaviour
Which volatile fatty acid is a problem with poorly fermented feeds?
Butyrate
Which two volatile fatty acids can cause depression of food intake?
Acetate and propionate
What are some examples of factors that decrease voluntary feed intake?
Body fatPregnancyInert fillDiet neutral detergent fibre
What effect does water drunk with dry food have on voluntary feed intake?
Little effect - water in material can have a significant effect
How can the water within plant material affect the feed intake of animals?
Contains soluble fibre or non-starch polysaccharides - these slow down passage of feed through the intestine
What is the nutritional value of feed dependent on?
Rate of feeding
Describe inert fill
Filling the rumen with an inert object to reduce intakeIntake drops and flow rate increases but not enough to match intake drop - feed is not fermented to the same degree
What is the main factor that affects rumen outflow rate?
Particle size reaching the omasum
What affects the particle size of food reaching omasum?
Ease of feed breakdown by chewing and fermentation
What disturbs the outflow rate from the rumen?
Ruminal acidosis
Describe the glucostatic theory of post digestive feedback
Glucoreceptors in CNS sensitive to rate of glucose useLow glucose use excite neural activity leading to hunger and food intake, high use has the opposite effectPeripheral arterio-venous glucose differences are an index of use rates by receptors in CNS
What is the main source of glucose in farm animals?
Hepatic gluconeogenesis from amino acids and propionic acid
What level is ruminant plasma glucose concentration compared to non-ruminants?
One half
How sensitive is the ruminant CNS to changes in blood glucose?
Not very - insensitive
What is the hepatic oxidation theory of post digestive feedback?
ATP levels in the liver detemine vagal stimulation with low levels stimulating hunger centre
What are the three sources for ATP in the liver?
Volatile fatty acidsBeta-hydroxybutyric acidNon-essential fatty acids
Describe the thermostatic theory of post digestive feedback
Animals eat to maintain body temperature but not good in ruminants as rumen is exothermicMost animals eat to avoid hypothermiaPoultry the relationship between intake and maintenance of body temperature is good
Describe the lipostatic theory of post digestive feedback
Control of mammalian energy balance, body weight and composition involves a hypothalamic feedback loopBody fat reserves modulate food intake and energy expenditure with the greater the fat store the lower the appetiteLeptin is produced by fat tissue with the more fat the more leptin and has negative effects on feed intakes
What is the cow’s metabolism completely devoted to?
Support of mammary metabolism
What does the energy deficit of cows cause a reduction in?
Plasma leptin
How could a reduction in leptin benefit early lactating dairy cows?
Promotes a faster increase in feed intake and diverts energy from non-vital functions such as reproduction
Give some examples of what the amount animals eats depends on
WeightAgeGrowth rateHealthEnvironmentNon production activityStressPalatabilityFood typeWaterAvailability
What is the dry matter intake of a dairy cow calculated as?
2.5% of body weight + 10% of milk yield
What is a good estimate of the DMI for most adult animals?
2% of body weight
What are the two sources of energy in forages?
Cell contents - sugars,starches, proteins etc. >90% digestible and rapidly availableCell walls - cellulose, lignin hemicellulose etc. - 40-70% digestible and more slowly available
Which part of the forage is neutral detergent fibre part of?
Cell walls
What is neutral detergent fiber most useful in?
Balancing rumen-healthy rations and predicting how much forage a cow can consume
What is the best single measure of forage quality?
Neutral detergent fibre
What is the acid detergent fibre value used for?
Predicting the energy content of forages as it is inversely related to digestiblity
What is the maintenance feed intake for a dairy cow?
65MJ for a 650kg Holstein
What is the feed intake requirement for milk production?
5MJ/litre
What are the pregnancy requirements for feed intake?
40MJ required at term
What do tannins lead to if eaten in large quantities by a ruminant?
Precipitating the enzymes secreted by microbial bacteria and reduce fermentation in the rumen thus reducing DMI
Describe the actions of protease inhibitors in ruminants
Inhibit activity of trypsin, chemotropism and other proteasesFound in beans and peas but also in cereals, potatoes and other productsPresence results in impaired growth and poor food utilization longer transit times and lower intake
What do lectins/humagglutinins result in?
Poor food utilization and impaired growth
What effects have been demonstrated by glucosinolates?
Thyroid function effects
What are glucosinolates found in?
Cabbage and related species especially oilseed rape
What is the relationship between silage quality and pH?
Positive at low pHNegative at high pH
What is pica?
Depraved appetite
What does pica include?
Persistent licking, chewing or eating of wood, soil, rags, bones etc.
Which type of cattle is pica mainly a problem in?
Outdoor cattle
What may sporadic cases of pica indicate?
Primary or secondary brain disorderToxicityMetabolic disease
Why may herd outbreaks of pica arise?
ParasitismMineral deficiencyUnder nutrition
Which cows does slurry drinking occur in?
Herd problem in calved cows wintered indoors or in yards
Why is slurry/urine drinking undesirable?
Can spread infectious agents
What are some suggested causes of slurry/urine drinking?
Metabolic disorders associated with high milk yield and low roughage intakeSubclinical ketosisSubclinical acidosisMineral deficiency
When does magnesium deficiency arise in ruminants?
High demand is combined with decreased intake
How much regulation is there of magnesium?
Little homeostatic regulation
What two things can magnesium deficiency cause?
StaggersGrass tetany
What are the clinical signs of magnesium deficiency?
HyperaesthesiaEars twitchingSensitive to sound/hand clapStaggers and collapsesChamping of jawsSudden death
What are the clinical signs for sub acute magnesium deficiency?
Slow onset over 3-4 daysSpasmodic urination and defecationMuscle tremorStaggering gait
What are the clinical signs for chronic magnesium deficiency?
Few signsPoor appetiteDepressed milk yieldIncreased heart rate
What are the causes for magnesium deficiency in ruminants?
Low magnesium levels in the dietPoor feed intakesPoor absorption of magnesium
What level of magnesium should it not drop below?
<0.5 mmol/l
Describe the treatment for magnesium deficiency
URGENTBottle Ca borogluconate with Mg hypophosphate, i/v, slowlyMagnesium sulphate 25% s/c only
How can magnesium deficiency be prevented?
Magnesium alone is not very palatableMgO in concentrates, mix with molassesMg bolus oralMg tablets/flakes added to drinking waterAvoid K fertilizer when hypomagnesium is a known problem
What does calcium deficiency cause?
Bovine parturient paresisHypocalcaemiaAcute flaccid paralysisMilk fever
What is the normal level of calcium within the blood?
2.3 to 3.2 mmol/l
Where is calcium absorbed from?
GIT, kidney and bone
What does calcium require as a co-factor at several stages?
Magnesium
What are the subclinical signs of calcium deficiency?
HypersensitivityAble to standExcitableTremorsEar twitchingAtaxiaBloat/gas in gut
What levels of blood calcium cause subclinical signs?
1.8-2.3 mmol/l
What levels of blood calcium cause moderate clinical signs of calcium deficiency?
1.2-1.8mmol/l
What are the clinical signs presenting with moderate clinical calcium deficiency?
RecumbentDepressedDry muzzleCold extremitiesBloat/gas in gutNo defecationDelayed/absent pupil responses
What levels of blood calcium cause severe clinical signs of calcium deficiency?
Reduced consciousnessLateral recumbencyUnresponsive to stimuliMuscle flaccidityReduced cardiac outputBloatDeath
Describe the treatment for calcium deficiency
URGENT20% Ca borogluconate 400ml40% Ca borogluconate 400mlLow volume treatments Maxacal 100mlAlso some mixed with Mg, P and glucoseI/V slow while monitoring heart rateS/C deposit to prevent recurrence
What is the cause of calcium deficiency in ruminants?
Demand is not met by supplyKidney absorptionGIT absorptionBone reserves
How can calcium deficiency be prevented?
Low calcium in dry cow rationHigh calcium in milking cow rationMagnesium supplyDCAB - dietary cation anion balanceDrench at calvingBolus just before calving
What are the three things that make cows more at risk of calcium deficiency?
OlderFatterChannel breeds
How can you detect phosphorus deficiency in cows?
Local conditionHappy downerNo response to Ca/MgFoston I/V
What are the cations and anions in the balanced diet?
Cations: Na and KAnions: Cl and S
How should DCAB ions be analyzed?
mmol/kg dry matter
What is the formula used to measure ion levels in a DCAB feed?
(Na+K)-(Cl+S)
What level should DCAB be lower than?
-200 mmol/kg dry matter
What can anionic salts do?
Not very palatable and reduce DMI - can cause negative energy balance, fatty liver and metabolic problems
How can anion levels be monitored?
Monitor urine pH - aim for 5.5-6.5If drops to 5.0-5.5 too many anions are being absorbedCheck several cows every week
What are the examples of important macro elements?
CalciumMagnesiumPhosphorous
What does calcium deficiency cause in cattle?
Milk fever
What does magnesium deficiency cause in cattle?
Staggers
What are the examples of trace elements?
CobaltCopperSelenium (Vitamin E)IodineIronMolybdenumZinc
What are trace elements?
Elements essential for normal function
What are grazing livestock dependent on for nutrients?
Soil/plants
What are the two methods of providing mineral supplementation?
Additional feedAdding into concentrates
When are supplementations frequently given?
When not needed or without any evidence for need
WHat can unnecessary supplementation result in?
WasteExpensesHarm to animals
What is poor production/fertility often blamed on?
Trace Element DeficiencyProblem usually caused by husbandry/management or disease
What is the main difference between primary and secondary deficiencies?
Primary - soil/plant deficiencySecondary - lack of absorption in the animal
What can copper deficiency be related to as a secondary deficiency?
Excess molybdenym, sulfur or iron as they bind copper in the rumen
Why is local knowledge important for determining trace element deficiencies?
Deficiencies are common in certain geographical areas - knowing what’s local can help diagnose
What is cobalt an essential component of?
Vitamin B12 - involves in glucose pathway
What is seen with cobalt deficiency?
Poor thrift in growing animals - usually seen in lambs
What species is cobalt deficiency most diagnosed in?
Sheep
What are the clinical signs for cobalt deficiency in sheep?
Non-specificPoor thrift in weaned lambsLethargyPoor growth ratesPoor appetitePoor BCSPale mm (anaemia in late stages)Eye discharges
How can cobalt deficiency be diagnosed?
Vitamin B12 assay on blood samplesUrine - MMALiver samples - Vit. B12 from abattoirSupplementation trial - over 8-10 weeks compare to controlsPCV
What are the clinical signs of cobalt deficiency on PME?
Non-specificEmaciationBone marrow hypoplasiaLiver enlarged in severe cases
What is the treatment for cobalt deficiencies?
Vit. B12 injection with cobalt sulphate oral drench
Monthly drenching with cobalt
Cobalt oxide boluses
What can be a problem with using cobalt oxide boluses in sheep?
Sheep can cough them up again
What do selenium and vitamin E protect against?
Free radicals
What are selenium and vitamin E?
Cellular antioxidants
What can Se/Vit. E deficiency cause?
Membrane damage and tissue necrosis
Which muscles and cells are particularly susceptible to Se/Vit E deficiency?
Skeletal Cardiac Respiratory RBC
What are the names of some clinical diseases caused by Se/Vit. E deficiency?
White muscle disease Stiff lamb disease Nutritional muscular dystrophy
Describe clinical Se/Vit. E deficiency
White muscle disease Congenital causing stillbirths/neonatal deaths Sudden onset of stiffness Affected lambs bright but appear in pain Have lowered head carriage Deteriorate and remain recumbant Muscles painful and swollen Associated with recent stress
Describe sub-clinical Se/Vit. E deficiency
Poor growth rates Embryonic death (ewes) Increased disease susceptibility Reduced milk production Increased retained foetal membranes
How can Se/Vit. E deficiency be diagnosed?
Clinical signs Glutathione Peroxidase decreased in blood Creatine Kinase increased in early stages Vit. E assay in blood Histopath. on cardiac muscle
Describe the treatment/control of Se/Vit. E deficiency
Se injection Vit. E injection Correct supplementation of pregnant ewe/cows ration Drenching of growing lambs Boluses
What should you beware of when treating Se/Vit E deficiency?
Toxicity
What trace element is an essential part of many enzymes?
Copper
Give some examples of enzymes that copper is an essential part of
Cytochrome oxidase (myelin formation) Caeruloplasmin (iron release into plasma) Lysyl oxidase (elastin and collagen synthesis) Tyrosinase (pigmentation)
What are the clinical signs presenting with Cu deficiency?
Growing cattle
- Poor thrift
- Diarrhoea
- Poor coat colour
Lambs and adult deer
- Swayback
Uncommon
- Bone fragility
What is copper deficiency often in association with?
Poor nutrition
What is a very serious and common problem in sheep relating to trace elements?
Coppper toxicity
What are the clinical signs of Cu toxicity?
Depression Anorexia Haemolysis Haemoglobinuria Jaundice
What would be found on investigation of copper toxicity?
AST>1000 U/l serum Low PCV Gastroenteritis Swollen dark grey kidneys (Gun Metal Kidneys) Liver enlarged and friable Cu assays of kidney >3000 umol/kg DM
What is iodine required for?
Synthesis of thyroid hormone
What are the two presentations of iodine deficiency?
Clinical - goitre in new-born Sub-clinical - increased perinatal mortality
What proportion of the herd is usually affected by trace element deficiencies?
More than 1 animal Sometimes a history of deficiency in the area
What is usually a good sign of trace element deficiencies in young animals?
Poor growth
What is usually more useful than testing soil or plants for trace element deficiency?
Testing the animal itself
What are the four methods of supplementing trace elements in farm animals?
Oral dosing Injection Slow release rumen capsule Addition to fertiliser
What do you need to beware of when supplementing trace elements?
Copper and selenium toxicity
What should you monitor when using supplementation of trace elements?
Effectiveness
What four things should cause you to suspect trace element deficiencies in farm animals?
More than 1 animal affected Poor thrift Gait abnormalities Goitre
What are the two most susceptible species to copper deficiency?
Cattle
Deer
What is the most susceptible species to cobalt deficiency?
Sheep - cobalt requirements higher
Why is it better to test animal levels of trace elements than those in the plants?
Levels within plants can vary depending on:
- Type of plant
- Part of plant tested
- Where it’s growing
- Season
- Soil contamination
Absorption in animal will vary
Requirements of animal varies according to physiological status and age
How would you test selenium status in animals?
3 blood samples
- No store so blood good place to check
- Little variation in levels between animals
- Only need small number
What is the best place to test to assess copper levels in animals?
Liver
- Copper stored here
- Blood can be of some value to confirm deficiency
- Large variation so test as many as possible
