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Flashcards in Bovine Respiratory Disease Complex Deck (31):
1

What are the 3 strains of bovine herpes virus and what disease do they cause?

BHV1 - respiratory disease and abortion
BHV2 - infectious pustular vulvovaginitis
BHV4 - metritis

2

At what age do you see BHV1 causing clinical signs of respiratory infection in calves?

6 months to 2yo

3

At what stage of gestation does BVD cause foetal absorption and abortion?

1st trimester 0-95 days

4

At what stage of gestation does BVD create persistently infected animals?

95-120 days

5

At what stage of gestation does BVD cause congenital lesions, a seropositive foetus or abortion due to placentitis?

120-285days 3rd trimester

6

What congenital lesions does BVD cause?

Cerebellum hypoplasia
Micropthalmus
Cataracts

7

What causes BVD mucosal disease and what are clinical signs?

Persistently infected animal becomes infected with a cytopathic biotype

CS: oral ulceration, ill thrift, diarrhoea, respiratory disease due to immunosuppression

8

How can you diagnose BVD?

Bulk milk tank testing
Ear notch tissue test - when calf is tagged at 9w
Check 5 blood ELISAs per group

9

How can you control BVD?

Vaccination before first breeding
Test bought in animals
Test Bulls blood and semen
Biosecurity
Test and cull PIs

10

What are the components of the bovine respiratory disease complex?

1. Bovine herpes virus 1 - infectious bovine rhinotracheitis
2. Parainfluenza virus 3 - flavivirus
3. Bovine viral diarrhoea - pestivirus
4. Respiratory syncitial virus - pneumovirus

11

What are the gross lesions associated with Respiratory Syncitial Virus on PM?

Emphysematous lungs
Multinucleate giant cells
Air bullae
Alveoli have clumped together

12

What are the post mortem findings with IBR (BHV1)?

Necrosis of the tracheal mucosa

13

What is the pathogenesis of BVD leading to respiratory disease?

Immunosuppression makes PIs more susceptible to respiratory disease
- destruction of alveolar macrophages
- depleted lymphoid tissues

14

What bacterial agents commonly cause respiratory disease in cattle?

1. Mycoplasma bovis
2. Pasturella
- Mannheimia haemolytica
- Pasteurella multocida
- Histophilus somni

15

What should you treat mycoplasma infections with?

Oxytetracyclines or macrolides
(Target DNA synthesis - no cell wall)

16

What other diseases can mycoplasma bovis cause?

Septic arthritis (joint ill) - calves
Otitis media
Mastitis
Conjunctivitis
Pneumonia

Only significant if found the in the LRT - commensual in the URT

17

What are the typical post mortem lesions associated with mycoplasma?

Cuffing pneumonia - lymphocyte cuffing around bronchioles
Cranioventral atelectasis

18

What aetiological agents are responsible for Shipping Fever?

IBR (BHV1) followed by Mannheimia haemolytica

19

What presentations does Histophilus somni cause?

Myocardial abscesses
Pleuritis
Pericarditis
Arthritis
Thrombomeningoencephalitis

20

How can you treat Histophilus somni?

Usually too late - acutely fatal

21

How can you prevent bovine respiratory disease?

4L colostrum in 1st 6h, another 4L in the next 6
Improving housing and husbandry
- reduce SD, improve hygiene and ventilation
Vaccination increases herd immunity

22

What aetiological agents can you vaccinate against?

IBR only - Rispoval
BVD + IBR - Bovillis
BVD only - Bovella

23

Why are cows so susceptible to respiratory disease?

1. Small lung volume
2. Large respiratory dead space
3. Alveoli easy to damage and difficult to recover
4. No collaterals ventilation of the alveoli
5. Early and substantial vasoconstriction of arteries and arterioles
6. Persistent fibrinous exudate and lung scarring

24

What is the cost of calf pneumonia?

Death
Poor growth
Delayed age at first calving
Drugs costs
Reduction in subsequent milk yield
Other disease

25

What defines failure of passive transfer?

Plasma proteins <56g/L
Serum proteins <52g/L

26

What are predisposing factors to respiratory disease?

Bad air quality - ammonia, too dry / humid, too cold
Immunosuppression - SARA, BVD, stress eg weaning / disbudding
Overstocking and large group sizes
Larger than a 2 week spread between age groups

Most common during the housing period in winter

27

What are the similarity and differences between PI3 and RSV?

PI3 - Young calves
RSV - calves and older calves

Lower respiratory tract infections - classic viral pneumonia

Can vaccinate both

28

What are two viruses that causes lower respiratory tract disease?

PI3
RSV

29

What type of respiratory disease does BHV1 cause?

Upper respiratory tract infection
Ocular and nasal discharge, Pyrexia, milk drop

30

How do animals present with secondary pasteurellosis?

Following a stressful incident - shipping fever
Acute dysponea and septicaemia

31

What are the lower critical temperatures for calves in different conditions?

0c - no draught
9c - draughty
15c - wet floor