Sheep respiratory disease - pathology

Question 1

6 common conditions of the lungs (& their distribution)

Answer 1

• Enzootic (cranioventral uni/bilateral)
• Fibrinous (cranioventral uni/bilateral)
• OPA (focal/multifocal)
• Muellerius (multifocal)
• Dictyocaulus (dorsocaudal)
• Abscesses (diffuse)

Question 2

Pasteurella pneumonia/septicaemia in lambs

Answer 2

• affected parts of the lung are usually the cranioventral lung regions
• feel consolidated/hard, not spongy

Question 3

Pleurisy

Answer 3

• can occur for various reasons: as a result of a bout of Pasteurella pneumonia which the lamb survives, or as a complication of navel ill or a bacterial infection picked up around birth
• as a rule, the drier the beige deposits, the more longstanding the lesions

Question 4

Pasteurella (trehalosi) septicaemia

Answer 4

• fast-acting septicaemia which typically affects lambs in Autumn during bad weather or after movement (stress)
• the carcase has haemorrhage all over
• throat LN are enlarged
• may be defects, reddening or a green/beige deposit on the lining of the oesophagus

Question 5

Enzootic (Mycoplasma ovipneumoniae) pneumonia

Answer 5

• slowly progressive
• usually non-fatal condition
• causes a cough and usually reduced growth rates
• can be an incidental finding, or may be seen in lambs’ lungs at slaughter
• characteristic small white foci with areas of purple heavy lung
• lesions are always in the cranioventral lung lobes

Question 6

Lung abscesses

Answer 6

• not necessary to open the abscesses to make a diagnosis when touch is as accurate
• an abscess will be smooth and tense and gives slightly untouched
• with CLA the abscesses are irregular and firmer with laminated pus
• OPA masses are solid and don’t have a capsule

Question 7

Chronic lung abscessation/endocarditis

Answer 7

• can be a source of conditions loss and death in older sheep
• caused by a focus of infection somewhere getting into the bloodstream and settling out in the lungs or heart valves
• if it occurs at a high prevalence, needle hygiene and lameness control should be reviewed

Question 8

OPA

Answer 8

• lung tumour caused by Jaagsiekte virus
• causes hard white areas, sometimes large consolidated regions, sometimes speckled, in any part of the lungs
• usually in adult ewes
• usually much white froth in airways

Question 9

Ovine parasitic pneumonia

Answer 9

• lead shot lesions

Question 10

Dosing gun injuries

Answer 10

• essential to open up the throat of any sheep being examined, remove the tongue and have a look underneath, otherwise these injuries will be missed