996 Veterinary Obstetrics 



The teat remains empty, the nodule in the teat is very evi- 

 dent, and above it are the milk canals, widely distended by 

 the imprisoned milk. A chronic catarrh of the epithelium ap- 

 parently exists with the new formation of dense sclerotic con- 

 nective tissue in the form of a nodule. If left alone it has 

 little tendency to cause marked mastitis. In a large propor- 

 tion of cases, however, the use of the milk tube, sound, or 

 other implement, creates a wound and deposits virulent infection 

 in it, resulting finally in mammitis. If left alone the nodule finally 

 causes complete atresia, and the milk is imprisoned until the intra- 

 mammary pressure reaches the point at which milk secretion can- 

 not be continued, after which the quarter commences to atrophy. 



The process is a chronic one, may continue to develop and in- 

 crease week by week, but usually does not advance far enough 

 to bring about complete atresia during the milking period when 

 its appearance is first observed. After the cow is turned dry, 

 however, the process continues, and leads usually to complete 

 atresia, so that at the next calving, it is found that the affected 

 teat is completely closed at its base, making it impossible for the 

 milk to enter the cistern from the larger canals. 



The disease may affect but one teat, or may involve two, three, 

 or all of them. It behaves clinically as a chronic infection, and 

 appears to spread from one quarter of the cow to another, until 

 each is involved and ruined. We have observed each of the four 

 quarters of the udder ruined consecutively because of such nodu- 

 lar growth at the base of the teat. After the cistern has been 

 completely closed at the ba.se, the disease extends down, and in 

 many cases brings about a complete obliteration of the cistern 

 and the teat canal'. 



In many other instances the atresia has its beginning in an 

 ulcer involving the milk orifice. First there arises difBculty in 

 withdrawing the milk from the cistern. If the nipple is carefully 

 examined, it will be found to have a small, hard, sclerotic ma,ss at 

 the teat orifice, usually not painful. If the milk orifice is care- 

 fully inspected, there is frequently observed a red, angry ulcer, 

 involving the milk meatus at the apex of the teat. I,ike the 

 preceding disease, the course is chronic and insidious. 



There is, however, no limitation of the area in which the sclerotic 

 enlargement may occur. While most of these changes are ob- 



