Acute Mammitis 945 



exposing the udder and teats to increased danger from contu- 

 sions and abrasions ; intensifies the danger of forcible contact 

 of the teat orifice with infected objects; and favors the entrance 

 into the teat of straws or other rigid infection-bearing bodies. 

 The disease may occur, however, at any date during the period 

 of milking, or in the dry cow. We have observed the disease 

 in heifers. 



Usually only one quarter of the udder, most commonly a pos- 

 terior one, is involved. The disease may simultaneously or con- 

 secutively affect two, three or all of the quarters. ■ 



The period of incubation in acute mammitis is brief. Experi- 

 mental infection has induced the symptoms of mammitis in 12- 

 24 hours. We also observe a similar period of incubation clini- 

 cally following operative interference of the mammae. The 

 forcible insertion of a milk tube ; the inflation of the udder in 

 milk fever ; or the overcoming of atresia of the teat by incision 

 or puncture is frequently followed by mammitis in 1 2-24 hours. 



Lameness is a common and early symptom of the disease. 

 It is frequently the first symptom observed by the owner, 

 though it may occur at any time during the disease. The lame- 

 ness may be referable to three different causes. 



I. In the first stages of the disease, the owner may observe 

 lameness as the first symptom of mammitis. In such cases the 

 lameness is apparently an expression of pain in the affected 

 quarter or quarters. The lameness may be more severe when a hind 

 quarter is involved than when an anterior one is affected, because, 

 in progression, the posterior quarter is more severely compressed 

 or contused by the hind leg as the limb is carried forward and 

 weight placed upon it. Doubtless not all the pain and conse- 

 quent lameness is due to the sensitiveness of the affected quarter, 

 but must be largely referred to lymphangitis or phlebitis of the 

 chief mammary veins and lymphatics in their course through 

 the inguinal canal, where any tenderness causes intense pain dur- 

 ing any movements of the limbs or bod}-^ which may bring into 

 play the surrounding muscles. When both sides of the udder 

 are simultaneously inflamed, the disinclination to move becomes 

 very strong, with evidences of very great pain. 



2. Pyaemic arthritis may arise at any time during the affec- 

 tion, as a complication of mammitis, and induce 'symptoms par- 

 allel in all respects with the pyaemic arthritis already described 

 60 



