PREVENTIVE MEDICINE 323 



and mammitis. The use of teat syphons on cows hard to milk 

 has been often blamed for causing mammitis, and knitting needles 

 and even straws picked up from the floor of the byre are sometimes 

 used for enlarging the teat canal. Cows in full milk are more 

 susceptible to infection than those in a dry or a semi-dry condition 

 owing to increased vascularity of the udder, and to the fact that 

 the teats in many cases are more patent. Both dry cows and virgin 

 heifers do, however, become affected with mammitis, and in the 

 West of England the author has frequently seen the disease in the 

 latter class of stock while at grass. One fact which is well recog- 

 nised is that the entrance of bacteria into the udder is facilitated 

 by the teat canal being left full of milk often with a drop still 

 dependent from the orifice. 



Predisposing causes of mastitis are an unsanitary condition of 

 the byre, whereby the animals have to lie in filth and the udders are 

 seldom, if ever, clean, and any condition which would lower 

 the animal's natural powers of resistance. Draughts, especially if 

 toward the cow's hindquarters, are commonly held responsible for 

 the diseased conditions of the udder, but in this connection it must 

 be remembered that draughts, entering the cowshed beneath an ill- 

 fitting door, for instance, are more noticeable and have a more pro- 

 nounced effect in byres in which a too high temperature is main- 

 tained, and in which the atmosphere is foul and moist. Where 

 the internal temperature is maintained only a few degrees above 

 that prevailing outside, draughts are not so appreciable. 



PREVENTIVE MEASURES. The byre must be constructed on 

 approved lines so that the cows can lie down in comfort and yet 

 keep their udders clean. Udders should be wiped over with a clean, 

 damp cloth both before and after milking, and at the end of milk- 

 ing the teat must be left free from milk. There is no reason why 

 the udder, or at least the teat, should not be wiped over with a cloth 

 rung out in some mild and non-irritating disinfectant such as lysol. 

 Under no circumstances should the fore milk be milked on to the 

 floor of the byre, and the practice so frequently seen of milking 

 out a diseased udder on to the straw should be strongly condemned. 



The restricted housing accommodation found on all farms and 

 dairies too frequently precludes the possibility of isolating infected 

 animals or those with any suppurating sores or such as have not 

 properly cleansed. Nevertheless, cases should be isolated where 

 opportunity exists. A milker should not attend to sick animals, 

 especially to such as have sores or purulent discharges. If practic- 

 able, milking in the byre should be abolished, and a proper milking 

 shed provided. 



