Respiratory Disease in Cattle: Causes Flashcards
What are the ‘design’ issues of bovine lungs?
- Small lung volume for body size
- Large dead space- limited reserve, reduced phagocytic activity, decreased clearance of bacteria
- No collateral ventilation of alveoli- no pores of kohn, small area of pneumonia can prevent gaseous exchange
- Alveolar easily damage- collapse easy, difficult to ventilate
- Poorly developed fibrinolytic systems- persistent exudate, lung scarring
Other then ‘design’ what causes increased chance of respiratory disease?
Host defences may be additionally reduced:
* Failure of passive transfer- plasma TP <56g/l, Serum TP <52g/l
* Local defences- URT mucociliary carpet damaged by inapproriate air quality
* LRT inflammatory cells- immunosuppressoin
What are the consequences of respiratory disease?
- Death
- Poor growth
- Drug costs
- Delay in age at first calving
- Reduction in subsequent milk yield
What are causal organisms of bovine respiratory disease?
- RSV- respiratory syntical virus
- PI3- parainfluenza
- IBR- infectious bovine rhinotracheitis
- BVD- bovine viral diarrhoea
- Pasturella-
- Manheimia
- Histophilus
- Mycoplasma
- Dictylocaulus viviparous
- Enzootic pneumonia of calves
How does tha environment affect respiratory disease?
Level of challange is affected by managment of the environment
Pathogen multiplier effect:
* Mixed age groups
* Shared airspaces
* Group size
* Overstocking
* Multi-sourcing calves
Seasonal effects:
* Limited housing- mixed age, clos proximity
* UV light kills virus
* Virus thrive in damp conditions
* Viruses decay faster in dry conditions
What are the lower critical temperatures of a 4 week old calf in the following conditions?:
1. No draught
2. Some draught
3. Damp floor
- No draught- 0 degrees
- Some draught- 9 degrees
- 15 degrees if floor is damp
Damp and draught make you shiver sooner
- What causes Husk?
- How is it caught?
- What is reinfection syndrome?
- Lung worm- ditylocaulus viviparous
- At pasture ingest larvae
- Cattle with prior partial immunity, re-infected (allergic reaction)
What is fog fever?
How is it prevented?
- Acute pneumonia- 4-10 days after move to lush pasture
- D,L- Tryptophan to 3-methylindole to 3 methylene-indolenine
- Open mouthed breathing and frothing- tachypnoea, anxiety
- > 1 yo single or group
- If moved likely to die- steroids
Prevention
Move into new pasture gradually
- What agent causes calf diptheria?
- Where are lesions?
- What are the clinical signs?
- What causes the initial infection?
- How is it treated?
- What can be caused subsequently?
- Fusobacterium necrophorum
- Lesions in mouth/pharynx/larynx
- Pyrexia, difficulty eating/swallowing, smell
- Mucosal injury, erupting teeth, bad hygiene
- Treat with ABs
- Laryngeal chrondritis- breed related, ABs, NSAIDs, tracheotomy/tracheostomy
What causes shipping fever?
Adult cattle associated with stress (moving) with agents BHV-1 and manhaemia
Sudden/Severe
What are the consequences of bovine respiratory disease?
- Vena-caval thromboembolism
- Diffuse fibrosing alveolitis
- Acute exudative pneumonia
- Aspiration pneumonia
What breeds of cattle are predisposed to respiratory disease?
Channel Island and Friesian:
Atopic rhinitis- allergic rhinitis
Enzootic nasal granuloma
What respiratory disease not yet in the UK is notifiable?
Contagious bovine P pneumonia
What are the signs and differentials of vena-caval thromboembolism?
- Profuse nosebleed
- DDX- foreign body
No treatment- slaughter
