74 an:nual reports of department of agriculture. 



By contributing to the arriA^al of the stock in the best possible condi- 

 tion, the revised regiihitions are a factor leading to a continuance of 

 our export trade in live stock. During the .year numerous shipments 

 of both cattle and swine Avere made to South American points under 

 export certificates issued by the bureau. 



PROGRESS IN DISEASE CONTROL. 



The long and anxious campaign Avhich the bureau has been waging 

 against animal diseases brought encouraging results during the last 

 year. From a scientific point of view, victory over most of these 

 maladies is in sight, and in a number of cases eradication is nearly 

 complete. (See accompanying charts.) 



Cattle scabies, Avhich in IDOG Avas prevalent in nearly one-half of 

 the United States, noAV appears only as outbreaks in limited areas. 

 These outbreaks are being suppressed. 



Eradication of sheep scabies, Avhich in 190G existed in more than 

 one-half of the land area of the countrA^, is noAv about nine-tenths 

 complete. 



The cattle tick Avhich causes, Texas fever has had its domain re- 

 duced from more than 700,000 square miles in 1906 to less than 

 300,000 square miles in 1918. Progress has been continuous 3- ear 

 after year. 



Hog cholera presents a someAvhat different problem, as the nature 

 of the disease makes the campaign of a sporadic character. But the 

 use of antihog-cholera serum, especially in connection Avith virus, is 

 a definite means of preA enting serious outbreaks. 



Eecent investigations have slioAvn that the common intestinal 

 roundworm of the pig is not onW injurious as an intestinal parasite 

 but that during an early stage of its development, Avhile still micro- 

 scopic in size, it invades the lungs and may give rise to seriotis 

 troubles. Furthermore, pigs that survive this invasion of the lungs 

 may never fully recover, but fail to groAv properly, and become un- 

 proiitable runts. It is believed that much of the damage caused l)y 

 the intestinal roundAvorm can be avoided by simple sanitary pre- 

 cautions, the practical application of Avhich is noAV being tested. The 

 problem of so called " mixed infection" is also under in\'estigation, 

 Avith the vieAA of determining more definitel}^ its relation to hog 

 cholera and the proper measures of control. 



The United States has remained free from foot-and-mouth dis- 

 ease, and the bureau continues to exercise A'igilance against its possible 

 introduction. Serious outbreaks in foreign countries have been 

 closely studied, and bureau inspectors have given special attention* 

 to caigoes of live-stock products from such countries, importations 

 of the animals themselves not being permitted. 



A questionnaire inquiry made among stockmen and State officials 

 indicates an almost uuIa ersal support of the method Avhich the bureau 

 employed successfully in stamping out past outbreaks of foot-and- 

 mouth disease b}^ slaughter of the animals affected. 



Eradication of tuberculosis has progressed as fast as the Avork 

 could be handled by the veterinary force employed; in fact, there 

 has been a waiting list of herds to be tested. Under present authority 

 from Congress only one-third of the apprapiation for tuberculosis- 



