Cattle Flashcards
What design issues do bovine lungs have?
Small lung volume:body size
Large dead space - limited respiratory reserve, reduced phagocytic activity, decreased bacteria clearance
No collateral ventilation of alveoli - small area of pneumonia can prevent gas exchange in lots of alveoli
Alveoli easy to damage and difficult to recover - alveolar collapse is easy, re-pneumonisation is slow
Early and substantial vasoconstriction of arteries and arterioles - meant to maintain BP but cuts off blood supply to lung
Poorly developed fibrinolytic systems - lung scarring
Consequences of bovine respiratory disease?
Death Poor growth Drug costs Delay in age at first calving Reduction in subsequent milk yield Related diseases
Estimated UK prevalence of enzootic pneumonia of calves?
Dairy - 30%
Beef - 80-90%
Infectious causes of pneumonia in cattle?
Viruses - RSV, PI3, IBR (BVD)
Bacteria - Pasteurella, Mannheimia, Histophilus
Mycoplasma
See 3rd year lectures
What may cause reduced host defences, causing a calf to be more prone to pneumonia/resp disease?
FPT - too little, too late, poor quality
Inappropriate air quality -> URT mucociliary carpet damaged
LRT inflammatory cells immunosuppression:
- stressors (weaning, disbudding, castration, movement)
- sub-acute ruminal acidosis
- BVD
What should the plasma and serum TP be for calves?
Plasma TP > 56g/l
Serum TP > 52g/l
Why is Bovine respiratory disease most common in winter?
Mixed age groups/limited housing
Close proximity of age groups
UV light kills viruses - less sun
Viruses thrive in damp conditions and protected by water droplets
Viruses and bacteria decay faster in dry conditions
What are the lower critical temperatures of a 4 week ofd calf with no draught, some draught and damp floor? What about a younger calf 0-2 weeks old?
No draught (0.2m/s): 0C Some draught (2m/s): 9C Damp floor: 15C
0-2 weeks can’t tolerate lower temperatures - need 15C
How long can a calf gut absorb antibodies from colostrum?
12 hours
How close in age should calf groups be? Why?
<2 weeks spread between youngest and oldest
Older calves act as pathogen multipliers
Cattle Lungworm life cycle?
Adults in URT Eggs containing L1 coughed up and swallowed Mature to L2 as pass through GIT L2 in faeces L2 -> L3 - spread by rain/pilobolus/wind L3 eaten on pasture Mature to L4 and migrate through gut wall Spread to lungs via bloodstream
What is the prepatent period for cattle lungworm?
3 weeks
Max humidity for cattle housing?
80% (65% better)
What is Fog fever?
Reaction to fructans in grass
Single animal
If moved, likely to die
Which dairy breeds have a genetic predisposition for atrophic rhinitis and enzootic nasal granuloma?
Channel Island
Fresian
Which beef breed has a genetic predisposition to laryngeal chondritis? Why?
Belgian blue
Lung volume:body weight lowest for any breed
Which respiratory diseases are fattening cattle most prone to?
Mannheimiosis/Pasteurellosis
Histophilus somni
Which respiratory disease are first lactation heifers turned out most prone to?
Parasitic pneumonia: Dictyocaulus viviparus
What bovine respiratory diseases are associated with an allergic response?
Bovine Farmers’ Lung - reaction to mould spores
Pre-patent lungworm
Fog Fever
What usually causes stertorous upper respiratory noise in cattle?
Laryngeal pathology - commonly laryngeal chondritis
- secondary to calf diphtheria (necrotic smell from mouth)
- breed predispositions
Treatment for laryngeal chondritis in cows?
May respond to penicillin/anti-inflammatories
May require tracheotomy/-ostomy
Causes of a profuse nosebleed in cows?
Vena caval thrombo-embolism - hopeless
Foreign body - blackthorn prickles
What to do for respiratory clinical exam of cattle?
Observe general appearance - overgrown coat = too cold
Ear position - depressed/cold
Watch their behaviour - seeking shelter? depressed?
Move around to elicit coughing
TPR
Resp noise - lung fields and trachea/URT
Respiratory depth
Posture - abducted elbows = air hungry
Deep breaths = air hungry
Shallow breaths = pain - pleurisy/peritonitis
Which animals to sample when investigating bovine respiratory disease? What to bear in mind when interpreting results?
Sample acute cases - before secondary infections invade
Pasteurella and Mannheimia are normal commensals
URT Mycoplasma may be commensal
URT organisms may not reflect the pathology in the LRT
Single antibody titres may be historic
Only sample if will be useful/affect decisions/affect treatment choice
What types of individual samples are needed to test for bovine respiratory diseases?
Nasopharyngeal swab: IBR (RSV, PI3)
Conjunctival swabs/scrape: IBR (Mycoplasma bovis if eyes affected)
Paired serology 2-3 weeks apart: All, rising titre/4 fold
BAL: M bovis, IBR, RSV, PI3, BVD, Histophilus
Faecal sample: D viviparus (Baermann technique)
What group sample can be used to help investigate dairy herd respiratory disease?
Bulk milk antibodies
Useful for trends
First lactation heifers only indicates recent entry into herd
How to assess the environment when investigating bovine respiratory disease?
At level of the animals! Urea? Warm air? Underfoot squelch test Too cold/hot? Dust in air? Does it make you cough? Temperature of the bedding Smoke tests Data loggers for temperature and humidity
Short term/immediate treatment for bovine respiratory disease?
Antibiotics in an outbreak
NSAIDs
Nursing Isolation/reduce numbers
Longterm prevention of bovine respiratory disease?
Improve environment
Colostrum and nutrition
Vaccination
What to do if group of cattle affected by bovine respiratory diseases?
If only treating those affected, need to take daily temps (treat if >39.5/40)
Or if >25% group affected, could treat metaphylactically - more practical
Which broad spectrum, long acting antibiotics are most commonly used for respiratory disease in cattle?
Oxytetracycline
Beta lactams (not for Mycoplasma)
Florfenicol
Macrolides (licensed for calf pneumonia) - Tilmicosin, tulathromycin, gammithromycin, tildipirosin
Fluoroquinolones - only if c+s suggests only thing that would work as public health issues
What type of vaccine are IBR vaccines? Why is this good?
Marker vaccine
gE protein deleted from the virus in the vaccine
So Abs are different to those produced against intact virus and can be differentiated on serology
Can tell difference between vaccinated animal vs naturally infected
Routes of IBR vaccine administration? How often are boosters needed?
Intranasal (faster but local effects, IgA)
Intramuscular
6-12 monthly boosters recommended
Difference between IBR live and dead vaccines?
Live - CMI to deal with recent infection locally, can use in face of infection intranasally to be followed by systemic dose
Dead - provokes Ab levels
Young animals receive live vaccine initially with dead boosters
Non cardiac signs of bovine cardiac disease?
Reduced production Exercise intolerance Increased urine output Syncope Poor appetite when failing
What to subjectively assess without touching animal for bovine cardiac disease?
Condition score
Visible oedema - inter-mandibular, brisket
Posture
Respiratory effort
How to interpret bovine skin tone/tenting? Other signs seen?
4-6% loss normal (PCV 40%)
6-8% tenting 2-4s (PCV 50%) - dry nose and mouth
8-10% tenting 6-10s (PCV 55%) - cold extremities +/- recumbent
10-12% tenting 20+s (PCV 60%+) - comatose, shock
12%+ Death
What to assess on hands on exam for bovine cardiac disease?
Skin tone
Regional temperature for perfusion - ears
Mucous membranes - mouth, conjunctiva, vulva: CRT, dry, cold, colour
Causes of pale mucous membranes in bovines?
Anaemia -deficiencies - iron, copper, cobalt -toxicities - kale, nitrate etc -blood/protein loss - haemonchus, fascioliasis, Johne's, sucking lice, PGE, red water, leptospirosis Poor perfusion -shock (RDA) -heart failure -thrombosis
Causes of red mucous membranes in bovines?
Toxaemia Salmonellosis Pasteurellosis Malignant catarrhal fever Infectious Bovine Kerato-conjunctivitis IBR
Causes of cyanosis of mucous membranes in bovines?
Respiratory failure
Nitrate/nitrite, metaldehyde poisoning
Congenital cardiac abnormality - calves
Causes of jaundice of mucous membranes in bovines?
Hepatitis Haemolytic anaemia (Babesia-red water) Photosensitisation Ragwort, kale, lupin, copper poisoning Post-partum haemoglobinuria Leptospirosis
Causes of haemorrhage mucous membranes in bovines?
Anthrax Bracken Sweet vernal grass posioning Copper toxicity (acute) Leptospirosis Mycotoxicosis
Normal pulse rate in calves and cattle?
Calves: 100-120
Cattle: 50-80 (high yielders up to 95) - give fluids if 100+ with skin tent
120+ suggests primary cardiac disease
What happens to the jugular and subcutaneous abdominal (milk) veins in cardiac failure?
Distension in right sided failure
Increased venous pressure in cardiac failure
How to assess the jugular pulse in a bovine?
Normal up to 1/3 way up
Occluse or empty jugular to check in abnormal
All way up:
-endocarditis, pericarditis, haemothorax, hydrothorax, congestive heart failure, valvular stenosis/insufficiency
-sporadic bovine leukosis-thymic form
-enzootic bovine leukosis-cardiac form
Where to auscultate the heart in bovines? Base, apex, left contact, right contact, pulmonary valve, aortic valve, left AV valve, right AV valve?
Base: 3rd-6th rib
Apex: 6th rib at articulation of rib to sternum, 2cm cranial to diaphragm
Left contact: 3rd rib ro 4th intercostal space
Right contact: Ventral part of 4th rib
Pulmonary valve: 3rd intercostal space
Aortic valve: 4th rib 12cm above sternum
Left AV valve: 4th intercostal space
Right AV valve: 4th rib 10cm above sternum
Which cardiac sounds can be heard in bovines?
S1 (lub): ventricular contraction and AV valves shut = systolic
S2 (dup): closure of aortic/pulmonary valves = diastolic
Ventricular filling sound nor usually heard
S4: atrial contraction may be heard
What does it mean in bovines if S1 or S2 is loud?
Loud S1: increased force of contraction
Loud S2: increased pressure in vessels
Causes of heart murmurs in bovines?
Stenosis: rough, harsh Regurgitation/incompetence: softer, purr Endocarditis Congenital heart defects Interference with blood flow or inc turbulence - anaemia, myocardial weakness, extra-cardiac e.g ruminal tympany
When are valvular stenosis and incompetence murmurs heard in bovines?
If pre-systolic (before S1): left or right AV stenosis If systolic (after S1): left or right AV incompetence, pulmonary or aortic stenosis If diastolic (after S2): aortic or poss pulmonary incompetence
What causes endocarditis?
Needs persistent bacteraemia to occur e.g. after reticulates, nephritis, metritis, mastitis
T pyogenes, C chauvoei, E.coli
Mycoplasma - contagious bovine pleuropneumonoa
Streptococci, staph
Mannheimia
Clinical signs of endocarditis in bovines?
Persistent fever Pain on pinch test HR 100+ Shifting polyarthritis due to emboli Pulsation of mammary veins
Diagnosis of bovine endocarditis?
Take 20ml blood for culture
Neutrophilia with left shift, increased fibrinogen
What congenital heart defects can calves have? How do the murmurs sound?
Ventricular septal defects: often just ventral to aorta, systolic murmur (most common)
PDA: machinery murmur by day 5 (uncommon)
Patent foramen ovale (uncommon)
Tetralogy of Fallot (uncommon)
Aortic stenosis (uncommon)
Clinical signs of ventricular septal defects in calves?
Range from no effect to stunted growth to sudden death
No cyanosis
Clinical signs of PDA in calves?
Exercise intolerance and weakness
No cyanosis
What makes up tetralogy of fallot?
VSD
Pulmonary stenosis
Dextroposed aorta
Secondary ventricular hypertrophy
Clinical sign of aortic stenosis (persistent right aortic arch) in calves?
Milk regurgitation
What can cause myocardial weakness in bovines?
Septicaemia and infection - blackleg, foot and mouth, tetanus
Nutritional deficiency - copper, selenium, vitamin E
Poisoning - arsenic, mercury, phosphorous
What is pericarditis usually associated with?
Traumatic reticulitis
Clinical signs of traumatic reticulitis and pericarditis?
Shallow abdominal breathing
Abducted elbows
Tests for traumatic reticulitis and pericarditis?
Grunt or Eric Williams test
Bar (xiphisternum) test
Withers pinch
Treatment for traumatic reticulitis and pericarditis?
Surgery
Magnets
Antibiotics
Clinical signs of dilated cardiomyopathy in bovines? Age seen?
Peripheral oedema Jugular distension Fluid accumulations in body cavities Enlargement of heart with rounded 'globose' shape Well grown 2-3yo Holsteins
What is caudal vena cava thrombosis in bovines secondary to? When seen?
Secondary to liver abscess
1-3yo cattle - acidosis, rumenitis
Clinical signs of caudal vena cava thrombosis in bovines?
Peracute - dead in pool of blood
Acute - respiratory distress, pain, pyrexia
Clinical signs of respiratory effects of cardiac disease in bovines?
Nasal discharge - oedema, white and frothy
Bilateral epistaxis - in pulmonary embolism
Tachypnoea, cough - no pyrexia unless secondary infection
Clinical signs of adomen effects of cardiac disease in bovines?
Bilateral ventral distension due to ascites - abdominocentesis, ballotment
Liver enlargement - palpate right side behind ribs
Why is GI disease a common cause of cardiac arrhythmias?
Abdominal distension -> vagal stimulation
Acid-base and electrolyte imbalance
Pain -> increased sympathetic tone
What cardiac degenerative changes can bovines have?
Fatty change - reversible
Atrophy
Mineralisation - organomercurial posoning
Xanthosis - abnormal brown pigmentation of myocardium, esp Ayrshire cattle
What are vitamin E and selenium important for?
Needed by certain enzymes as antagonists of free radicals
What syndromes can myocardial degeneration and necrosis cause?
Abortion and perinatal mortality
Sudden death in neonatal calves
Predisposing factors = low bioavailability of Se or Vit E
Sudden death differential diagnosis for bovines?
Haemorrhage - calving injury, abomasa ulceration from NSAIDs Plant toxicity - yew Lightening Electrocution Hypomagnesaemia Hypocalcaemia Toxaemia - mastitis, metritis Bloat Blackleg Black disease Anthrax
What is the Older Cattle Disposal Scheme (OCDS)?
Replaced OTMS for cows born in UK before 1/8/96
Market support measure for disposal and compensation
Started in 2006 and ended in 2008
What is the Over Thirty Months Scheme (OTMS)?
Stopped in 2005
Market support as BSE prevented animals entering food chain
Fit for human consumption other than residues, so could be treated and money received
What is the rule for emergency slaughter?
An otherwise healthy animal must have suffered an accident that prevented its transport to the slaughterhouse for welfare reasons
Vet must be present at time of slaughter
Clean livestock policy?
Category 3 = dirty
Category 3 and obove - unable to proceed for normal slaughter
How must fallen stock (cattle) be disposed of?
Not burial or open burning
Collection by approved transporter for disposal or an approved treatment to a: knacker, hunt kennel, maggot farm, incinerator, renderer
Must be tested for BSE if >48mo
Animal by products must be transported in covered leak-proof containers/vehicles and be accompanied by a commercial document
What is NFSCo?
National Fallen Stock Company
Transfers wholly to industry - not for profit
Horses too
Free membership, £1.75 admin fee per month if service used that month
Actual cost charged by approved collector minus any government contribution
Who can register as a fallen stock collector? How may they charge?
All premises approved under the Animal by-products regulations
Knackers, hunt kennels, maggot farms, renderers, incinerators
Can charge by standard container, weight for poultry, headage
Anthrax procedure?
Must be an OV authorised to do anthrax tests
Farmer informs vet of sudden death
Vet phones local APHA office
OOH can do test then phone next working day
Given reference number if DEFRA want the test
Can do private investigation without telling ministry of negative finding but won’t be paid
APHA tell police and local authority if positive
What is ERDP? What happens to it?
Effective rumen degradable protein - any N containing compound
Fermented in rumen to produce NH4+
NH4+ used by microbes to produce microbial protein - digested in abomasum and SI
Fermentation and protein synthesis require energy
If insufficient ME or excess ERDP, NH4+ absorbed across rumen wall -> increased blood urea
What is RUDP? What happens to it?
Rumen undegradable protein?
Passes through rumen
Digested in abomasum and small intestine
e.g. Soya
How much protein does a dairy cow require? How much protein in grass silage?
14% if not milking (=135-145g DCP/kg BW)
16% if yield <8000L
18% if yield >8000L?
17% if yield 30L/day (=165-175g DCP/kg BW)
18.5% if yield 50L/day (=180-190g DCP/kg BW)
Grass silage = 12-18% protein
What is metabolisable energy?
Energy available to animal for maintenance, growth, lactation and pregnancy
Assumes a healthy rumen and microflora
Megajoules per kg of dry matter
What is the rumen capacity?
200L+
What are carbohydrates fermented to in the rumen?
VFAs - acetate and butyrate (from cellulosic foods), propionate (from starch and sugar foods)
CO2
CH4
Speed of fermentation: fibre < starches < sugars
What happens to VFAs?
Absorbed across rumen wall (health of papillae important)
Enter Krebbs cycle
Glucose synthesis from propionate (gluconeogenesis) = 1/3 of energy production
DMI BW % for dry/normal, lactating and pregnant cows?
Dry cow: 2-2.5% BW (falls gradually in first 7 weeks, then rapidly falls in last week pre-calving to 1-1.5%)
Increases post calving (peaks at 4-10 weeks)
- Lactating cow: 3%, or 2.5% BW + 0.1 x yield (L)
- Lactating 30L/day: 3% BW
- Lactating 50L/day: 4% BW (aim is 4% at peak yield)
Correction factors: - Complete diet (e.g. TMR): + 20-30% - Out-of-parlour feeder: + 5-10% - Mixed forages: < 5% - Breed Holstein: < + 20% - Heifers with cows: - 5-10% - Self feed silage: - 5-10% Electric fence at silage face: - 10-20% Poorly preserved silage: - 10-30% Week of lactation: < - 45%
What influences ruminant DMI?
Body weight and fatness (fat cows eat less)
Milk yield (more milk, eats more)
Stage of production cycle
Type of food (digestibility/rate of passage)
Palatability
Access - feed barrier, electric fence etc
Availability
Social factors e.g. bullying of heifers
Stress/pain e.g. lameness
Rumen health
How much energy does a holstein dairy cow require?
Maintenance: 65MJ
Production: 5MJ/L milk
Weight gain/loss: 30MJ/kg BW
Late pregnancy: 20MJ for early dry period, 40MJ for transition period (average of 30MJ ME/day from 1 month pre calving)
What does milk yield depend on?
Genetic merit
Nutrition
Health
What is the generic potential for milk yield of modern holsteins? And what is the national average?
Potential: 13,000L
Average: 8,500L
What is M/D?
Energy density of food
Lower = ‘healthier’
The more food eaten, the lower the M/D needs to be for milk yield
When is peak milk yield reached?
At around 8 weeks of lactation
Why are cows in negative energy balance postpartum? What is the target BCS loss? How much is 1 BCS point?
Depressed DMI in first weeks post partum coincides with massive energy demand for milk production
Even best fed dairy cows lose weight in early lactation
Target loss: 0.5-1 BCS points
1 BCS point = 50kg BW
How to maximise DMI in lactating cows?
Maximise intakes in dry period but avoid getting fat
Palatable diet - mixed forages
Avoid SARA - forage:concentration ratio, change diets slowly (3 week rumen adaptation period)
Environment - comfort, feed space, social aspects
Health e.g. lameness
Aims for M/D for lactating and dry cow diets? Pasture DMI?
Lactating cow M/D: 12 MJ/kg DM
Dry cow M/D: 8-8.5 (<10) MJ/kg DM
Pasture DMI: no more than 14kg/day
DM and M/D of clamp grass silage, maize silage, big bale silage, hay, straw, grass and concentrates? Protein?
Clamp grass silage: DM 30%, M/D 10.5, protein 15%
Maize silage: DM 35%, M/D 11.5, high energy, high starch (FME) and low protein (9%), poor fibre source so feed straw/hay with it
Big bale silage: DM 30%, M/D 9
Hay: DM 85%, M/D 9
Straw: DM 85%, 6.5
Grass: DM 20% or less, M/D 11
Concentrates: very dry, M/D 12.5, high FME, high proteins, no fibre
What different feeding systems are there for lactating cows?
Total mixed ration (TMR) - all food at barrier 24hr/day, complete diet
Traditional - silage at barrier and cake in parlour, grazing in summer
Hybrid -
Buffer feeding - TMR supplement to grazing in summer
Features of TMR for lactating cows?
All food at barrier 24h/day Complete diet - forage and concentrate is balanced Diet set for given yield e.g. M + 35L Assumes DMI M/D 11.2-12.4 If cow yields more, she can eat more Encourages maximal DMI Constant pH
Features of traditional feeding systems for lactating cows?
Grass silage fed at barrier May get mid-day feed on top of silage Cake in parlour - fed to yield Grazing in summer Peaks of acidity after milking
Features of a hybrid feeding system for lactating cows?
TMR at barrier and cake in parlour
How to monitor a cow’’s nutritional status?
Observation - BCS changes, DMI, cudding, rumen fill, faeces, cleanliness, long time
Production?
Milk quality - monthly recording, milk protein (low = energy deficit), butterfat (low = lack of fibre, high = high fibre diet, very high in early lactation as excessive fat mobilisation)
Biochemistry - metabolic profiles (ideally 12 cows/group, interpret using thresholds ie how many out of 12 are over threshold value)
What metabolic profiles can be used to assess the nutritional status of a cow? When to test? Cut offs and targets?
BHOB (a ketone body) - fresh cows (5-50 DIM) - suggestive of NEB - cut off >/= 1.4mmol/l (target is <10% of cows, 0.9mmol/l in UK) NEFA (evidence of fat mobilisation) - dry cows 2-14d before calving - cut off >/= 0.4mmol/l (target is <10% of cows) Urea - palace of protein and FME
How to assess a feed?
Smell, consistency
Evidence of sorting (need long fibre 1-4in long, will sort and select if too long)
Paper analysis (M/D)
Feed surface
Feed barrier
Should always be food in front of cow
DM - rule of thumb 25% easily squeeze water out, 30% cannot squeeze water out
What is the four diet model?
Should all be the same:
- diet formulated by nutritionist
- diet mixed by farmer
- diet received by cows
- diet cows require
What factors affect the four diet model?
Dry matter content Reliability of feed analyses Farmer tinkering e.g. adding extra fodder Farmer weighing and mixing Feed barrier space DMI estimates used in calculations
What should the fodder:concentrate ratio be for feeding cows? How slowly should a diet be changed? What is slug feeding?
concentrate/fodder maximum 60:40, 40:60 better
Change diets over 3 weeks
Slug feeding = max 2kg cake in one feed (avoid Dolly Parton effect)
Average calving index? How long is the dry period? Lactation period?
Calving index 370-400 days
60 day dry period
305-340 day lactation period
Why should you avoid cows getting fat in the dry period? What BCS is the aim for calving?
Will depress appetite
Aim to calve at BCS 2.5-3
What happens to the cow’s body during the dry period?
Mammary regeneration
Rumen development - large and muscular, big healthy papillae, suitable bugs for post-calving diet
What to feed in the first 5 weeks of the dry period? Why?
Low energy, high fibre About 1.5-2% BW DMI (10-14kg/day) Energy requirement = 90-100MJ M/D 7.5-8.5 MJ/day High fibre for rumen health Excessive energy at this time will suppress production and deposition of visceral fat? (suppress appetite, predispose to metabolic disease in lactation) Options: - Grass silage and straw (4-5kg straw) - Big bale silage - Hay - Grass but will get fat if not limited intake, so supply straw (3-4kg/day) and stock densely (5 cows/acre with sward height 7cm)
What to feed in the last 3 weeks of the dry period?
= transition diet
DMI declining
Energy requirements increasing: 110=140MJ/day
M/D 9.5-10 MJ ME/kg DM
Crude protein 13-15%
Options:
- Custom made
- High yielder TMR diet diluted with straw/hay
- Silage and straw and dry cow concentrate, dry cow mineral (high Mg, low Ca)
What is the ‘Keenan’ diet?
New strategy for dry cow feeding?
One diet for whole of dry period
Low energy ‘Goldilocks diet’: 95-100MJ/day, in 12-13 kg DMI, M/D 8-8.5
Chopped straw essential (2’’): 8-10kg/head/day
Adequate feed space - cows must eat a lot
Reduces social stresses - no moves
Dry cow management? What is done? Housing?
Stop milking
Teat sealant/dry cow tube - sterile
Move to dry cow group
Move to calving pen in early second stage earlier (not earlier - stress)
Or calve in group pen - Johne’s risk etc
Loose yard housing (1.3sq metre/1000L), large luxury cubicles (sand bed) - comfort important
Adequate feed barrier space (at least 90cm/cow), ideally more space and cubicles than needed
High comfort, low stress, low energy
What is Fat Mobilisation Syndrome (FMS) in early lactation? Potential cause?
Energy deficit (negative energy balance) -> excessive mobilisation of fat for energy
‘Fatty liver’
Similar to diabetes type 2 - insulin resistance
Obesity:
Decreased DMI in dry period and early lactation - increased weight loss in early lactation, reduced milk yield
Fat distribution in cows?
Subcutaneous fat - more in beef cows, fresians Visceral fat (hidden) - more in holsteins, channel island
Problem with overfeeding during dry period?
Little increase in CS but omental, mesenteric and peri-renal fat (visceral fat) increases by 55-80%
Decreased immune function - endometritis, mastitis
Risk factor for metabolic syndrome
BCS interpretation?
<3 fit
>3 obese
A measure of subcutaneous fat (visceral fat greater risk for FMS)
Problems associated with post natal depression?
Milk fever RFM/metritis/endometritis Mastitis Displaced abomasum Ketosis Fertility Lameness
What bugs are in the rumen?
Archaea - methanogens
Bacteria - mostly G+ve (and bacteriophages)
Fungi
Protozoa
What is the normal pH of the rumen? What happens if it falls?
pH 6-7
Low pH kills normal bug population and encourages growth of lactobacilli - produces lactic acid (cannot be metabolised)
Efficiency of digestion falls if pH falls
Low pH destroys papillae - rumenitis
Undigested particles pass through to handout and fermented
Osmotic diarrhoea (loose faeces)
Colonic acidosis - damage to colon wall (fibrin casts in faeces)
Factors affecting rumen pH?
How much acid (VFAs) produced
Type of acid produced (lactic acid is strong)
Rate of fermentation (fibre is slow, concentrates fast)
Rate of acid removal (absorption across rumen wall by papillae)
Buffering by saliva - chewing the cud
Amount of saliva produced by a healthy cudding cow? How many cows should be cudding at any time?
3.5kg/day - produced when chewing long fibre
70%
Contains sodium bicarbonate
What causes rumen acidosis?
Excessive concentrates - FME
Insufficient fibre
-> reduced saliva flow, increased acid -> rumen pH decreases
D lactic acid - cannot be metabolised, builds up
Why is long fibre good?
Encourages cudding - bicarbonate buffers acid
Forms a rumen mat - keeps food particles in rumen to be digested, home to bug biofilms
When is sub-acute rumen acidosis (SARA) seen? Signs?
‘Dolly Parton’ effect of large concentrate feeds
Herd problem, 30% of animals at risk, pH<5.5
Energy deficit - excess weight loss
Overall poor health
Loose soft faeces - variable (some cows ok, some loose)
Swishing tails (sore bums)
Undigested grain and long fibre present in faeces
Effects of SARA?
Reduced DMI
Reduced digestibility - reduce energy intake, NEB
Reduced milk yield
Reduced milk quality - butterfat may be low (not always), variable milk protein
Reduced fertility - not seen bulling, poor conception rates
Immunosuppression - disease susceptibility
Health - displaced abomasum (VFAs enter abomasum and cause atony), digestive upsets, ketosis, lameness (subclinical laminitis, ulcers, white line lesions), mastitis, infections - endocarditis
Diagnosis of SARA?
Clues - fertility, lameness, ketosis, LDA, faeces, odd sick cows
Observe - cudding, tail swishing, dirt score, BCS (dry->peak >0.5 loss)
Faeces - score 1-5, sieve faeces under running water (fibre >0.5in long, undigested grain, mucus casts)
History - nutritional management
Measure rumen pH (2-4h after feeding), <5.7
Selecting cows for sampling rumen pH?
Cows calved 14-21 days: still adapting to ration, DMI not yet maximal, assesses transition and early management
Cows calved 60-80 days: should have adapted to ration, maximal DMI, assesses overall diet quality
Sample 6 cows per group
Record parlour cake fed
Diagnosis when 2 cows from either group are below threshold pH
Technique for sampling cow’s rumen pH?
Restrain cow - nose and tail Site = level of stifle & 6-8in behind last rib Clip and scrub Local anaesthetic 3-5in needle, 16-18G Read sample immediately
What does grass silage quality depend on?
Grass type First or second cut Time of day (pm best for sugars) Moisture content Chop length Compaction in clamp Fermentation
Pathophysiology of acute ruminal acidosis?
Excessive acid production pH falls below 5 Lactic acid production predominates Lactic acid eating bugs killed off Cow cannot metabolise D lactate