480 HORSE, SWINE AND POULTRY DISEASES 



by a tuberculous sow presents another source of danger. There 

 are a number of other methods of infection which will be men- 

 tioned later, but they should be considered of minor importance 

 and must not detract attention from the leading factors in the pro- 

 duction of the vast majority of cases of hog tuberculosis, which 

 are unquestionably the milk and feces of tuberculous cattle. When 

 once these are controlled tuberculosis of swine will forthwith be 

 greatly reduced. (B. A. I. Cir. 188.) 



Infection from Cattle through Milk and Feces. We judge 

 from experiments made, in which hogs were fed large quantities 

 of milk from tuberculous cows, that of the two methods the ex- 

 posure of hogs to the feces or to the milk of tuberculous cattle the 

 former has by far the greater danger, entirely apart from the fact 

 that exposure to the feces, in the manner in which it occurs, is 

 never a simple exposure to one thing, but a general exposure to 

 all the infectious material that may pass from cattle irrespective of 

 whether they are milk-producing animals or riot. 



Beef cattle behind which hogs are turned are usually young 

 animals, and the percentage of tuberculosis among them, and more 

 especially generalized or advanced tuberculosis, is very low. Dairy 

 cattle, the average age of which is greater, show a much higher 

 percentage of disease, and for this reason hogs associated with them 

 will probably contract tuberculosis more frequently. This greater 

 frequency must not be attributed entirely to the milk the hogs 

 receive from the cows. No farmer and no dairyman who is ac- 

 quainted with the value of the undigested grain or other nutri- 

 ment in cattle feces as a food for hogs fails to feed as much of it 

 as he possibly can. At the Experiment Station of the Bureau of 

 Animal Industry several lots of hogs were kept, for experimental 

 purposes, under identically the same conditions with the excep- 

 tion that some, in addition to their other feed, received a few 

 shovelfulls of cow feces daily, and some a small quantity of milk. 

 The results showed conclusively that either feces or milk caused 

 an improvement in the condition of the hogs greatly in excess of 

 what can be accounted for by the actual nutriment contained in the 

 feces or milk. The feces when given with the ordinary feed pro- 

 duced results fully as good as the milk. Of three lots of hogs, 

 all of which received the maximum amount of mill feed they 

 could be made to eat, one lot was fed a small quantity of milk daily, 

 and one the nutriment contained in a small quantity of cow feces. 

 At the end of three months the hogs that received either milk or 

 feces were in equally good condition, and had made a gain in 

 weight of from 75 to 100 per cent greater than that made by the 

 lot of hogs fed purely on mill feed. 



It is a question whether the tuberculosis that occurs among 

 hogs associated with dairy establishments is not more directly 

 traceable to the feces of tuberculous cows than to skim milk. Tu- 

 berculosis cows with unaffected udders rarely secrete milk infected 

 with tubercle bacilli. The danger that milk may become infected 

 from the environment of tuberculous cattle is probably greater than 



