Respiratory Disease of Cattle

Question 1

What do lungs with bovine respiratory disease look like?

Answer 1

Dark red and congested in the cranio-ventral area

Question 2

What factors make up the susceptibility triangle?

Answer 2

Host
Environment
Pathogen

Question 3

What environmental factors influence the occurrence of bovine respiratory disease?

Answer 3

Housing
Ventilation
Stocking density
Mixing of livestock from other farms
Sharing air spaces with other age groups
Changes in weather

Question 4

What calf factors influence the occurrence of bovine respiratory disease?

Answer 4

Colostrum
Mixing of livestock
Transport
Homebred vs purchase
Nutrition
Standard husbandry

Question 5

Describe enzootic pneumonia in calves…

Answer 5

Affects grouped calves
See reduced feed intake
Dullness
Coughing often first sign noticed

Question 6

What should you do when you first approach a pneumonia case in cattle?

Answer 6

Stand and watch
Take history at same time
Listen for coughing
Count RR
- 20-40/min calves
- 10-30/min adults
Assess air quality
Look at ventilation
Stocking density

Question 7

What should you include in an individual examination when appraoching a cattle pneumonia case?

Answer 7

Temperature (>39.5)
Respiration (>40/min)
Auscultate lung lobes and trachea
Ocular-nasal discharge
Conjunctivitis
Gently pinch trachea

Question 8

Pathogenesis of enzootic pneumonia in calves…

Answer 8

1. Primary pathogen
   - Virus or mycoplasma damages resp tract
2. Allows for secondary infection causing more substantial damage

Question 9

What primary pathogen cause enzootic pneumonia?

Answer 9

Parainfluenza virus 3
BRSV
Coronavirus
BVDv
Mycoplasma spp.

Question 10

Which bacteria are important in causing secondary infections with calve enzootic pneumonia?

Answer 10

Mannheimia haemolytic
Pasteurella multocida
Arcanobacterium pyogenes
Histophilus somni

Question 11

How can you treat enzootic pneumonia in calves?

Answer 11

Antibiotics
NSAIDs
Treat anything with a temp >39.5
Metaphylaxis if over 25% group affected

Question 12

Describe follow up visit following treatment for enzootic pneumonia…

Answer 12

Revisit 24-48hrs
Asses temp and group again
Follow up treatment

Question 13

How can you identify the pathogens responsible for calf enzootic pneumonia?

Answer 13

Difficult!
Sample calves early stages of disease
PM dead calves
Transtracheal wash
BAL
Nasopharyngeal swab
Serology
Faecal exam

Question 14

Describe how a BAL is used to identify pathogens in calves…

Answer 14

Pass thin tube via nostril into trachea
Flash in sterile saline
Immediately withdraw
Send sample to lab (APHA)

Question 15

Describe paired serology in calf pneumonia….

Answer 15

Identifying viral infections
Take 2 clotted blood samples 14-21 days apart
Demonstrate rise in antibody titre to virus agent
Slow wait for results

Question 16

How can you prevent another outbreak of bovine respiratory disease?

Answer 16

Adequate hygiene/ventilation
Colostrum management
Care when buying in
Care when mixing animals
Consider vaccination

Question 17

What pathogen causes IBR?

Answer 17

Bovine herpesvirus-1

Question 18

What are the clinical signs of IBR?

Answer 18

Respiratory disease
- Pyrexia
- Conjunctivitis
- Coughing
- Tracheitis
- Nasal discharge
Encephalitis
Reproductive failure
Abortion
Latent infection

Question 19

Describe latency of IBR…

Answer 19

BHV-1 becomes latent
Resides in trigeminal ganglion
Recrudesces and starts shedding again after stress
May be sero-negative despite latent infection

Question 20

How do you control IBR?

Answer 20

1. Know you status
2. Biosecurity
3. Vaccination
4. Eradication

Question 21

How can you identify the IBR status of a herd?

Answer 21

Dairy = check bulk milk tank antibody titre
Beef = sample cohort of animals
Monitor abortions

Question 22

Describe IBR vaccination…

Answer 22

Give vaccine before natural exposure = prevent respiratory disease and abortion
Live attenuated vs dead
IM vs IN
Conventional vs marker

Question 23

Advantages of live IBR vaccine…

Answer 23

Induces rapid immunity (40-90hrs)
Single dose
Young animals may need 2

Question 24

Advantages of intranasal IBR vaccine..

Answer 24

Local immunity
Local secretory IgA and interferon
Rapid immunity (48hrs)
Must enter nasal cavity

Question 25

Describe marker vaccines for IBR...

Answer 25

Distinguishes between infected and vaccinated animals (DIVA) | Marker vaccines only has gB antigens so if animal is gE negative = never encountered the virus

Question 26

Non-infectious causes of calf pneumonia?

Answer 26

Aspiration | Calf diptheria

Question 27

Describe calf diptheria 1. Signs 2. Causes 3. Treatment

Answer 27

``` Fusobacterium necrophorum Signs: Necrotic laryngitis Oral lesions Foul breath Swollen cheeks ``` Causes: Food trapped between teeth and buccal mucosa Stomach tubing damaging mouth Sharp teeth Treatment: AB Tracheostomty

Question 28

Causes of BRD in older calves (up to 2 years)

Answer 28

Shipping fever

Question 29

What stress factors can induce shipping fever?

Answer 29

``` Transport Handling Mixing of animals Sourcing from market Change in diet Quality of housing Air quality Change in climate ```

Question 30

Describe shipping fever...

Answer 30

``` Seen 10-30days after transport Sudden onset Pyrexia, depressed appetite, increased RR, cough, noise, grunting Found dead Severe and acute bronchopneumonia Severe welfare problem Economic loss with reduced growth ```

Question 31

What pathogens cause shipping fever?

Answer 31

Mannheimia haemolytica Pasteurella multocida Various others

Question 32

Describe vaccination for shipping fever...

Answer 32

Highly effective | Efficacy may be avoided by maternally derived antibodies

Question 33

Describe fog fever

Answer 33

Cattle over 2 years Within 2 weeks of moving to lush autumn pastures Up to 50% groups affected Commonly fatal and difficult to treat

Question 34

Pathogenesis of Fog Fever...

Answer 34

1. L-Tryptophan in grass 2. Indole Acetic Acid in the rumen 3. Converted to 3-meythl indole which is toxic to lungs

Question 35

Clinical signs of fog fever...

Answer 35

Sudden onset Affects groups Severe resp distress Froth at mouth Get distressed or die when attempt to move Subcutaneous emphysema over back and thorax

Question 36

Treatment of fog fever...

Answer 36

Removed from pastures Symptomatic - NSAIDs, diuretics, steroids? Guarded prognosis

Question 37

How can you prevent fog fever?

Answer 37

Restrict access to lush pasture Strip grazing Feed hay before and during initial period of new grazing pasture Avoid over fertilising pasture

Question 38

Describe bovine farmers lung

Answer 38

Hypersensitivity following inhalation of allergens from moulds House cattle with poor ventilation Acute = mouth breathing, coughing, drop in milk yield Chronic = weight loss and coughing Sometimes farmer has sam symptoms!