54 



CITY MILK SUPPLY 



the harvest was reaped in May of that year when 32.6 per cent, of the 

 cows reacted. Of 47 mature cows in 1906 only three remained in the 

 herd after 1909 and only five of those that went out did so for other causes 

 than tuberculosis which shows that when a herd of mature animals 

 becomes badly diseased it is probably best to consider the entire herd 

 affected and to treat it accordingly. In the breeding herd 170 different 

 females were tested and 50 or about 30 per cent, reacted. 



TABLE 26. TUBERCULIN TESTING AT ILLINOIS EXPERIMENT STATION, 1906-1912 



(HAYDEN) 



(a) Five of the reactors had reacted previously. 

 (6) Seven animals acquired by purchase. 



From May, 1906 to December, 1911, five mature bulls and 32 young 

 ones ranging from 6 months to 2 years of age were tested; three reacted, 

 of these, one that reacted was fed on sterilized milk like the other calves 

 but still developed the disease either because this milk was not always 

 properly heated or for some other reason. Besides these, 26 bull calves 

 under 6 months of age from sound cows were sold. 



In Table 27 are shown the results obtained from 19 of the purebred 

 cows that were quarantined in 1908 and from four others that were quar- 

 antined later. 



The quarantined herd was kept in existence for about 2 years at a 

 cost of $60 a head a year, or a total cost of $2,700 for the 2 years. During 

 that time the gross returns were approximately $4,436 making a net re- 

 turn of $1,736. The cost was probably greater than it would be for an 

 ordinary herd. 



The Disinfection of Stables. The disinfection of the stable is a 

 matter which must be carefully attended to on the removal from the herd 

 of animals suffering from tuberculosis or other infectious diseases. The 

 first step is to clean up thoroughly, being careful to scrape the manure 

 from the floor and walls and to sweep the stable clean so that the germi- 



