356 LUNGS AND PLEURA. 



If the symptoms persist or become aggravated, and suggest the 

 development of an abscess or gangrene, it is better to slaughter the 

 animal. 



BRONCHO-PNEUMONIA OF SUCKING CALVES. 



Young animals still with the mother, particularly calves during the 

 first few weeks of life, are liable to broncho-pneumonia of a specialised 

 character, as regards not only its causes, but its development and duration. 



Causation. The causes may be grouped under two principal heads : — 



(a) In slow or difficult cases of parturition, the foetus may be injured 

 whilst being delivered, as a consequence of direct compression of the 

 great blood-vessels, etc. (particularly of compression of the umbilical 

 cord, compression of the thorax in the cardiac region, or partial pre- 

 mature separation of the envelopes), and may thus by reflex action 

 make automatic inspiratory movements. 



Eespiration being impossible, inasmuch as the thorax has not yet 

 passed the posterior passages, such inspiratory efforts made during 

 the passage through the pelvis may cause amniotic liquid to pass into 

 the bronchi. This accident is particularly liable to occur during 

 deliveries with breech presentation. If, as happens frequently, the 

 amniotic liquid has become infected either prior to or as a conse- 

 quence of obstetrical manipulation, the result is fatal; for the pas- 

 sage of infected amniotic fluid into the bronchi develops a broncho- 

 pneumonia of a degree of gravity depending on the character of 

 infection. 



(b) By an entirely different mechanism broncho-pneumonia may 

 occur in sucking calves during the first few weeks of life, even in the 

 case of animals born in a vigorous condition, and kept in warm and 

 well-arranged stables. This form follows diarrhoea, and constitutes a 

 final complication which is always of very marked gravity, and in 

 most cases fatal. 



Such secondary broncho-pneumonia only occurs when the diarrhoea 

 has resisted treatment, and it is important to note that the pectoral 

 lesions appear at a time when the intestinal mischief seems to have 

 diminished, the diarrhoea having lessened or disappeared. This variety 

 of broncho -pneumonia of young animals is by far the most frequent. 

 It has been termed broncho-pneumonia of intestinal origin, and exactly 

 resembles, so far as its development and gravity are concerned, the 

 broncho-pneumonia in young infants described by Sevestre and Lesage. 



The term broncho-pneumonia, moreover, is not strictly correct, or 

 at least is not exclusive ; for the rapid forms often exhibit lesions 

 other than those of broncho-pneumonia. Post-mortem examination 

 reveals pleurisy and pericarditis. 



