FIFTIETH ANNUAL CONVENTION 111 



extensively, the percentage varying from 5 to 30 per cent 

 of the cattle population, while in certain others investiga- 

 tions indicate that less than 1 per cent of the total of beef 

 and dairy cattle are utberculous. 



Tuberculosis is known to exist also quite extensively 

 among cattle and swine in all the European countries; in 

 fact, no part of the world is known to be free from it abso- 

 lutely. There are, however, some restricted regions where 

 its presence is not known, or it exists to but a very moderate 

 degree. 



Until cattle from the eastern part of the United States 

 were introduced into the Middle Western, Western, and 

 Southern States, tuberculosis among live stock in those re- 

 gions was unknown so far as we know. The disease at that 

 time was confined to the herds east of Allegheny moun- 

 tains. It was known then that a considerable percentage of 

 herds in those States were affected, but live-stock owners 

 were not inclined to consider tuberculosis as of very great 

 economic importance or dangerous to human health. There- 

 fore very little progres was made in its eradication. As the 

 Central and Western States became settled and cattle were 

 moved westward the disease spread much more rapidly 

 than is generally realized. The spreading in those areas is 

 due, of course, to the fact that livestock industry occupies a 

 more important part in agriculture than in the Eastern 

 States. Cattle are traded in more extensively and are con- 

 tinually being shipped and trailed from State to State and 

 from farm to farm. 



In some localities in the West, where dairying has de- 

 veloped extensively, it is now known that carload lots of 

 cows purchased in other States have contained 50 per cent 

 or more of tuberculous animals. Some herds of beef cattle 

 in our western country have become contaminated with the 

 disease by placing among them tuberculous pure-bred bulls 

 and cows that came from diseased herds elsewhere. The 

 importance of controlling tuberculosis and preventing its 

 spread by the interstate movement of diseased animals was 

 not so well recognized during the times of pioneer develop- 

 ment as it is today. Consequently in the absence of regula- 



