14 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



Hog cholera. — Hog cholera, always the cause of heavy losses 

 throughout the country, is less prevalent this year than for many 

 years. This is due, in marked degree, to the wise application of the 

 protective serum devised by the department and to the demonstration 

 work in certain selected counties. The beneficial results of the field 

 demonstrations are shown by a comparison of statistics for the 14 

 experimental counties before the work was undertaken and after it 

 had been in progress for a time. There was an increase in the num- 

 ber of hogs raised in these counties from 859,910 in 1912 to 1,334,644 

 in 1915, while during the same period there was a decrease in the 

 number that died from 152,296 to 30,668. This is an increase of 

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

 lost, or a total gain of 596,362 hogs. This demonstration shows what 

 can be accomplished by the use of serum with sanitary measures, and 

 undoubtedly has led to the extended use of such methods by farmers. 

 The experimental plan would be impracticable and too expensive 

 for the department to operate on a large scale, but the work will be 

 continued in a modified form. 



C ontagious abortion. — Contagious abortion in recent years has 

 reached such proportions as seriously to threaten the cattle-raising 

 industry. It strikes at the source by curtailing the production of 

 calves. It has been studied by the department, and vigorous efforts 

 are being made to advise stock breeders as to its nature and means of 

 prevention and eradication. The last Congress, upon the recom- 

 mendation of the department, made a special appropriation of 

 $50,000 for attacking the problem. 



Foot-and-mouth disease. — I am glad to be able to report the com- 

 plete suppression of foot-and-mouth disease during the year. The 

 disease appeared near Niles, Mich., late in the summer of 1914 and 

 reached 22 States and the District of Columbia. It extended entirely 

 across the country, from Massachusetts on the east to Washington on 

 the west, the region of greatest prevalence being from New York to 

 Illinois. 



After July 1, 1915, the disease occurred only in Illinois, Massa- 

 chusetts, New York, Indiana, and Minnesota. Before the end of 

 August it had been eradicated from the last three mentioned States. 

 It recurred in Massachusetts in October, 1915, and was promptly 

 suppressed. In Illinois the last herd of cattle affected by the natural 



