48 



CITY MILK SUPPLY 



no big cities; in fact, at the time these tests were made the largest con- 

 tained less than 35,000 inhabitants so that in no region is production 

 forced. Consequently there has not been the effort to develop large pro- 

 ducing cows of pronounced dairy type so that there has been little im- 

 portation of cattle from outside the State; the native cow has sufficed. 

 Cows are kept out-of-doors most of the year. So, bringing in the disease 

 has not been common and the cows have had a minimum of exposure in 

 infected barns. When the time comes that extensive importation of 

 high-bred stock becomes common there is danger, unless great care is 

 exercised, that tuberculosis may come with it, which emphasizes the 

 responsibility breeders have in this matter and which should spur them 

 on to acquire tuberculosis-free herds. 



Tuberculin Testing at Savanah, Ga. In 1914-15 Dr. D. C. Gillies, 

 for the Board of Sanitary Commissioners of Savannah, Georgia, applied 

 the tuberculin test to the forty-seven herds supplying the city with milk. 

 Dairymen had practiced cross breeding freely so that the resulting type 

 of cattle, though superior to the native Piney Woods stock, is inferior 

 to that stock improved by the use of purebred bulls. The majority of 

 the herds were composed of grade Jerseys, Guernseys and Holsteins 

 with a few native scrubs. It was found that seventeen, or 36 per cent., 

 of the herds were absolutely free from tuberculosis, eleven, or 23 per cent., 

 contained suspicious reactors and nineteen, or 40 per cent., contained 

 positive reactors. In all, 1,523 animals were tested, of which 1,347, or 

 88.36 per cent, were non-reactors, seventy-nine, or 5.28 per cent., sus- 

 picious reactors, and ninety-seven, or 6.36 per cent., positive reactors. 

 Three herds furnished forty-five suspicious reactors (57 per cent, of all 

 of them) and sixty-six positive reactors (68 per cent, of all of them). 

 Dr. Gillies believes that tuberculosis was introduced years ago, and has 

 spread very slowly ever since. He found the native cattle almost without 

 exception free from tuberculosis and that the disease was not more 

 prevalent in one than in any of the other dairy breeds. The serious 

 feature brought out by the test is that 64 per cent, of the herds contained 

 either suspicious or positive reactors. 



Tuberculin Testing in Chester County, Pennsylvania. In Chester 

 County, Pennsylvania, the Supplee Dairy Co. conducted an anti-tubercu- 

 losis campaign under the direction of Lane with the results that appear 

 in Table 23. 



TABLE 23. TUBERCULIN TESTS IN CHESTER COUNTY, PENNSYLVANIA (LANE) 



