TENTH ANNUAL YEAR BOOK-PART VII 287 



some extent in all of tiie packing houses having federal inspection. But 

 there are many encouraging features to the problem which we shall not 

 overlook. Present reports from inspectors show that in several localities 

 there has been a material decrease in the number of tuberculous hogs 

 sent to market. One state in particular has shown most encouraging im- 

 provement. The disease has been studied until its manner of spread, and 

 the proper means of eradicating it are much better understood than they 

 v.ere formerly. 



An investigation confined to the middle west and carried on by the 

 Bureau of Animal Industry, consisted of tagging hogs hauled to market in 

 V. agons. Of 3,4£0 animals tagged it v. as learned that all of the affected 

 stock came from a few farms — less than 6 per cent. This lends encourage- 

 ment to the incentive to stamp out the disease by concerted action. 



Since hogs almost invariably contract tuberculosis through eating in- 

 fectious materia], it is evident that the most effective means of prevent- 

 ing and eradicating the disease must consist of feeding only such sub- 

 stances as are known to be pure and free from all tuberculosis taint. This 

 means that we must avoid feeding the milk that has been returned from 

 a public creamery after the butter fats have been removed, unless we are 

 assured that it contains no living tubercle bacilli; it also means that hogs 

 must not he permitted to follow a drove of cattle unless the cattle have 

 been proven to be free from tuberculosis. It may be stated here that 

 the danger of tuberculous infection to hogs from following a bunch of 

 fattening steers is comparatively very slight, but whenever there are a 

 number of milking cous included in the drove, the dangers are greatly 

 increased, and all such cows should be carefully tested with tuberculin 

 that the infected anmals may be removed from the herd, taking their 

 infectious material with them. If it should so happen that one of the 

 cows in the dairy has appeared unthrifty for sometime, and has at last 

 died, do not feed her carcass to the nogs with a view to saving as much 

 as possible out of a misfortune. Just consider for a moment that if 

 that cow has died from tuberculosis she has within her body enough 

 tubercle bacilli to infect fifty hogs, and the loss from fifty tuberculous 

 hogs would more than devour the amount saved by feeding the carcass 

 of the cow. 



In dealing with affected herds of cattle it has been found best in 

 most cases to apply the tuberculin test to the entire herd as a means of 

 selecting the tuberculous animals, but v.ith a drove of hogs in which 

 tuberculosis has appeared there can be no doubt that the best and surest 

 method of procedure will in nearly every case be found in the slaughter 

 of the entire drove as soon as they can be put in a marketable condition. 

 They should be slaughtered at an abattoir under federal inspection, so 

 that proper disposal may be made of affected carcasses. 



This means of removing from the farm all of the centers of infec- 

 fon which exist among its swine is made possible and practicable by the 

 ease with which a new drove may be built up from fresh foundation 

 stock. With cattle the offspring seldom number more than one to a 

 cow in a year, and the young cow does not produce until two years of 

 age. With swine reproduction may be expected when the young sow is 



