Respiratory Flashcards
what are some design issues of the bovine lung?
small lung volume for body size
large dead space
no collateral ventilation of alveoli
alveoli easy to damage and difficult to recover
poor fibrinolytic system
in terms of airway defence, what issue does having a large dead amount of dead space cause?
reduced phagocytic activity in these spaces means decreased bacterial clearance
why does no collateral ventilation of alveoli cause issues in cattle?
small areas of blockage/pneumonia can prevent gaseous exchange in large numbers of alveoli
what issue does having a poorly developed fibrinolytic system have?
fibrinous exudate persists leading to lung scarring
when does failure of passive transfer of antibodies fail?
too little, too late, too poor quality colostrum
how is passive transfer assessed in calves?
measuring total protein
what is the local defence of the URT of calves, and how can this be damaged?
mucocilliary escalators - damaged by inappropriate air quality
what is the local defence of the LRT of calves, and how can this be damaged?
inflammatory cells - damaged by immunosuppression due to stressors, SARA or BVD
what viruses commonly cause respiratory issues?
respiratory syncytial virus
parainfluenza
infectious bovine rhinotracheitis (herpes)
bovine viral diarrhoea
what bacteria can cause respiratory issues?
Pasteurella
Mannheimia
Histophilus
Truperella
what causes IBR?
herpes virus
what is enzootic pneumonia of calves?
an outbreak of pneumonia in a group of calves with varying pathogens
what are some factors which can cause a pathogen multiplier effect for enzootic pneumonia outbreaks?
mixed age groups
shared airspace between age groups
group size
overstocking
multi-sourcing calves
when animals are young and pre-weaned how big should the age gap be between them?
less than 2 weeks
how does winter time effect the spread of respiratory disease?
limited housing - mixed age groups
less UV light (UV kills virus)
virus thrives in damp conditions
what does the lower critical temperature of a calf mean?
the temperature at which the calf will shiver and there will be production losses
what is the lower critical temperature of a 4 week old calf?
0 degrees with no draught
9 degrees with draught
15 degrees if floor is damp
what stage of lungworm is the infective stage?
L3
why is the spread of lungworm difficult to control?
spread by pilobilus fungi so can blow over from neighbouring farms
what is lungworms prepatent period?
3 weeks
what is the issue with becoming reinfected with lungworm?
reinfection syndrome - cattle with prior partial immunity can have a severe allergic reaction (no faecal larvae seen)
what is fog fever?
acute pneumonia seen 4-10 days after moving onto lush pasture
how many animals are usually effects by fog fever?
normally just one in a group
what are the clinical signs of fog fever?
open mouth breathing/frothing
tachypnoea
anxiety
how can fog fever be prevented?
gradual introduce animals to lush pasture
what causes calf diphtheria?
Fusobacterium necrophorum
where are lesions of calf diphtheria seen?
lesion in mouth, pharynx and larynx (ulcerative necrosis)
what are the clinical signs of calf diphtheria?
mouth lesions
pyrexia
difficulty swallowing/eating
pungent smell (halitosis)
what are some possible risk factors for calf diphtheria?
mucosal injury
erupting teeth
unhygienic feed buckets
what can be used to treat calf diphtheria?
antibiotics - penicillin, oxytetracycline… (broad spectrum drugs)
what complication can calf diphtheria lead to?
laryngeal chondritis
what breeds are predisposed to laryngeal chondritis?
beef breeds
texel sheep
what is done to treat laryngeal chondritis?
antibiotics
NSAIDs
tracheostomy
what animals is shipping fever classically seen in?
adult animals that have recently been transported
what pathogens cause shipping fever?
BHV 1
(secondary Mannheimia)
how is vena caval thrombo-embolism treated?
none - slaughter
what respiratory conditions are channel island breeds and friesians predisposed to?
atopic rhinitis (allergic rhinitis)
enzootic nasal granuloma
what is your top differential for respiratory disease for cows at pasture?
lungworm
why should testing for disease not just be done on the dead stock?
they may have died due to a secondary cause
what are some possible stressors that lead to respiratory disease?
transport (shipping fever)
wean/disbud/castrate… (enzootic pneumonia)
how can you differentiate between fog fever and lungworm?
fog fever - few days after turnout
lungworm - few weeks after turnout (prepatent period)
what type of bacteria are beef cattle more prone to?
bacterial - mannheimia/pasteurella…
where is the pathology if stertorous upper respiratory noise is heard?
laryngeal (laryngeal chondritis)
what are the differentials for a nosebleed?
vena caval thrombosis
foreign body
what facial feature is a very good indicator of calf health?
ear position
what postural feature show a cow is breathing deeply?
abducted elbows (can show pain)
what type of discharge do you want to sample from eyes and nose?
serous (if purulent you’re guaranteed to find bacteria)
why can antibody titre not be that useful?
titres may be history (only shows exposure) - take two to see if they change
what is a nasopharyngeal swab good for isolating?
IBR, RSV, PI3 (good for viruses) - all the way to the back of the pharynx
what are conjunctival swabs/scrapes good for isolating?
IBR and M. bovis
what is bronchoalveolar lavage good for isolating?
M. bovis, IBR, RSV, PI3, BVD, haemophilus, lungworm
where should the tubes reach to when carrying out a bronchoalveolar lavage?
tracheal bifurcation
what are bulk milk antibodies good for monitoring?
trends (when antibodies rise and fall)
determining how disease entered a farm (young stock, certain lactation…)
what should be assessed about the environment when trying to diagnose respiratory disease?
urea, warm air
damp, dusty, bedding temperature
does it make you cough
(stack effect)
what are some indications of inadequate airflow in a building?
tiger stripes (stripes on corrugated roof)
cobwebs
what are common reasons for a poor stack effect?
insufficient bodies (biomass)
poor inlet/outlet
what are the short/immediate treatment options for respiratory disease?
antibiotics
NSAIDs
nursing
isolation/reducing number
what are general prevention methods for respiratory disease?
colostrum/nutrition
improve environment
vaccines
in a group of sick animals with respiratory disease, which ones should be treated with antibiotics? (in an ideal world)
pyrexic animals, then monitor others and treat on first day of pyrexia
in a group of sick animals with respiratory disease, which ones should be treated wit5h antibiotics? (in reality)
if more than a quarter of the group is effected then treat all of them
what are the considerations when choosing a drug?
spectrum of activity
ease of administration (drug and animal…)
long/short acting
licensing/cascade
cost
what are some good broad spectrum antibiotics for respiratory disease?
oxytetracycline
beta lactams - penicillin and cephalosporins
florfenicol
macrolide
fluoroquinolones
what is the issue with using beta lactams to treat respiratory disease?
don’t work on Mycoplasma spp. because they need a cell wall to act on
what are some macrolides available for respiratory disease?
tilmicosin
tulathromycin
gammithromycin
tildipirosin
what is the issue with tilmicosin?
only vets can administer it (absorbed through skin, fatal if inject yourself with it)
what is the issue with fluoroquinolones?
high priority group - should avoid using them
what is NSAID use for in respiratory cases?
pain relief, antipyretic, improve appetite
what are some NSAIDs that can be used for respiratory cases?
flunixin
meloxicam
ketoprofen
carprofen
what is the advantage of using ketoprofen or carprofen for treating respiratory disease?
they have a zero milk withhold (less useful if using in combination with antibiotic that requires a milk withhold)
when are vaccines administered for maximum effect?
before risk period
correct storage, dose, route, frequency and age
what is one way vaccines can be administered at an early age? (gets around MDA)
intranasally to promote a local reaction
what is the use of IBR marker vaccines?
can tell the difference between vaccinated and naturally infected animal
when is a live IBR vaccine used?
in the face of an outbreak it is given intranasally to provoke a cell mediated response
when is the inactivated IBR vaccine used?
in eradication programmes as it provokes antibody levels to reduce the shedding
what are some autogenous vaccines that can be made?
mycoplasma
salmonella
