70 



ANNUAL REPORTS OF DEPARTMENT OP AGRICULTURE. 



mers themselves in efforts to combat the disease. For the first six 

 months of the fiscal year this work was continued under the Bio- 

 chemic Division. From January 1, 1916, it has been under the 

 direction of Dr. O. B. Hess, leaving to the Biochemic Division the 

 scientific research work. This change was made in accordance with 

 the policy of the department to segregate research, extension, and 

 regulatory work from each other. 



In the county-control investigations 1,814 infected herds, compris- 

 ing 77,141 hogs, were treated, with a loss of 11,905 animals, or 15.4 

 per cent. There were 26,174 hogs in these herds showing evidence 

 of disease at the time of treatment. 



The results following treatment of infected herds with antihog- 

 cholera serum, either alone or in combination with hog-cholera virus, 

 since the beginning of the work, are shown in the following table. 

 From these results it is safe to conclude that, in the case of herds 

 affected with hog cholera, the loss after treatment should not exceed 

 14 or 15 per cent of the treated hogs, provided the serum alone or 

 the serum and virus is applied promptly after the disease appears. 

 It is well known that without treatment the losses in such herds 

 would average from 80 to 85 per cent. The practical value of this 

 treatment seems therefore to be conclusively established. This table 

 includes only herds infected with hog cholera before the treatment 

 was applied. Experiments have shown that the use of the serum 

 before exposure to infection gives practically absolute protection 

 against the disease. 



Results of serum treatment of herds infected with hog cholera, 1913, 1914, 



and 1915. 



Condition of hogs and kind of treatment. 



Hogs sick when treated: 



Simultaneous (serum and virus) 

 Serum alone 



Total 



Hogs apparently well when treated: 

 Simultaneous (serum and virus) 

 Serum alone 



Total 



Grand total 



Number 

 treated. 



2,448 

 83,099 



85,547 



81,289 

 67,300 



148,589 



234,136 



Number 

 died. 



713 

 23,990 



24, 703 



3,070 

 3,063 



6,133 



30,836 



Per cent 

 died. 



29.1 



28.8 



28.8 



3.7 



4.5 



4.) 



13.1 



in order to bring out clearly the benefits which have resulted from 

 these county control investigations, the next table is submitted. No 

 official hog-cholera work of any sort was carried on in these counties 

 in 1912. In 1913 work was conducted in only 3 counties, namely, 

 Dallas County, Iowa, Montgomery County, Ind., and Pettis County, 

 Mo. In 1914 and 1915 work was carried on in all of the 14 counties. 

 •The table shows that in these counties there was an increase in the 

 number of hogs raised from 859,910 in 1912 to 1,334,644 in 1915, 

 while at the same time there was a decrease ki the hogs that died 

 from 152,296 in 1912 to 30,668 in 1915. This means an increase of 

 474,734 in the total number raised and a decrease of 121,628 in hogs 

 lost. On an average each of these counties raised 33,909 more hogs 

 in 1915 than in 1912, and at the same time lost 8,687 fewer in 1915 

 than in 1912, thus indicating a net gain per county of 42,596 hogs. 



