BUREAU OF ANIMAL INDUSTRY. 73 



bureau has given much study. The protection of human health 

 against tuberculosis from animal sources may be reasonably assured 

 by the pasteurization of milk and the inspection of meats. But there 

 remains the economic problem of eliminating the heavy and increas- 

 ing losses due to the insidious spread of this disease among farm 

 animals. 



Cattle and hogs are the most susceptible species and the only ones 

 that need to be considered. There is abundant evidence of the wide 

 prevalence of tuberculosis among these animals. Statistics of tuber- 

 culin testing indicate that on an average over 10 per cent of the dairy 

 cattle in the United States are affected with tuberculosis, and in the 

 Federal meat inspection 2| per cent of the beef cattle and 9 per cent 

 of the hogs inspected during the past fiscal year were found to be 

 so affected. The annual losses directly caused by this disease are 

 estimated at $25,000,000. In the face of growing demands and 

 higher prices for food products the Nation can not afford to ignore 

 indefinitely such an enormous leakage in its meat and milk supplies. 



The most practicable avenues of approach to the problem of tuber- 

 culosis eradication seems to be through the pure-bred herds of breed- 

 ing cattle and the feeding of hogs. This means simply the applica- 

 tion of the old principle of purifying the stream at its source. Many 

 herds of fine pedigreed cattle have harbored tuberculosis, and many 

 a stock raiser wishing to improve his stock has instead brought dis- 

 aster to himself by the introduction of tuberculous pure-bred animals 

 into his herd. 



Hogs, because of the early age at which they are slaughtered, do 

 not propagate the disease among their own kind to any appreciable 

 extent, but acquire it from cattle either by drinking infected milk 

 or by following cattle in the feed lot and feeding upon the undigested 

 grain in the droppings. Raw skim milk returned from creameries 

 to patrons and fed to pigs is a prolific source of the disease in swine. 

 The milk from many herds is mixed at the creamery, and if even one 

 lot has the germs of tuberculosis in it the entire quantity may become 

 infected. The remedy for this is simple — merely to pasteurize all the 

 skim milk before allowing it to leave the creamery. This should be 

 required by law. 



The elimination of tuberculosis from the pure-bred herds should 

 be accomplished gradually by utilizing the tuberculin test in conjunc- 

 tion with other appropriate measures. In any event the cooperation 

 of the Federal and State Governments and individual breeders will 

 be necessary. One of the first steps should be to spread among the 

 people concerned a knowledge of the facts as to the nature of tuber- 

 culosis, how it is spread, and how it may be prevented. 



HEMORRHAGIC SEPTICEMIA OR SHIPPING FEVER OF CATTLE. 



The disease variously designated as hemorrhagic septicemia, ship- 

 ping fever, and stockyards fever has been recognized in this country 

 for the past 20 years, but the losses have been unusually large 

 during the past year. Numerous outbreaks occurred during the fall 

 of 1915 and the spring of 1916 in the Central and Northwestern 

 States. The disease has appeared mainly among young cattle in 

 public stock markets or recently shipped through public stockyards, 

 but it has also been found to affect cattle of various ages and some- 



