956 
ANIMAL DISEASES 
Figure 9. — Fibrinous pneumonia in a calf lung is re- 
lated to a species difference in fibrinolytic activity. 
HE X 125. 
common (about 0.2% of feedlot cattle) their ef- 
fects on respiratory function are so great that 
investigators need be aware of the possible ex- 
istence of the disease. 
Emphysema 
Emphysema in calves/^ unlike that in man, 
is primarily interstitial. Severe interstitial em- 
physema is sometimes found as an artifact in 
older calves that have been euthanatized. The 
lesions are presumed due to agonal gasping and 
forceful respirations that over-distend the al- 
veoli. The artifact can be avoided by careful 
euthansia. 
Pulmonary Nematodiasis 
Incidental infections by the bovine lungworm 
(Dictyocaulus viviparous) are recognized at 
surgery or autopsy when pink subpleural lob- 
ules in the diaphragmatic lobes fail to collapse. 
Further examination may reveal wedge-shaped, 
dark red lobules at the posterior margins of the 
diaphragmatic lobes (where in the bovine ter- 
minal bronchioles are near the pleural surface) 
and similar lobules scattered patchily through 
the other lobes about the major bronchi. Dissec- 
tion of the lesions reveals long, slender, white 
worms in the bronchi along with frothy, muci- 
nous exudate (Figure 11). Microscopically, the 
lesions are characterized by chronic catarrhal 
bronchitis and emphysema (pink lobules) or 
atelectasis and consolidation (red lobules) . 
RESPIRATORY DISEASES OF SHEEP 
Rhinitis and Sinusitis 
Chronic, serous and catarrhal rhinitis and 
sinusitis are characteristic of virtually all 
sheep. A major cause of rhinitis and sinusitis is 
myiasis, infestation with larval stages of Oes- 
FiGURE 10. — Bilateral fibrononecrotic laryngitis in a 
calf caused by Fusiformis necrophorus. 
