4 BULLETIN 131, TJ. S. DEPARTMENT OF AGRICULTURE. 



Fuller (1913) has described an outbreak of the stable fly along 

 the east coast of South Africa. All classes of animals are said to 

 have suffered greatly from worry and anemia. Many cattle were 

 killed, and horses and cattle stampeded into the sea and into rivers 

 to obtain relief. The outbreak followed heavy rains. 



The experimental evidence with regard to the losses due to flies 

 that is available in this country does not seem to indicate that they 

 are as a rule of such serious consequence as the foregoing statements 

 would lead one to believe. The seriousness of such outbreaks as 

 Bishopp and Fuller refer to can not be questioned. Carlyle (1899), 

 at the Wisconsin Agricultural Experiment Station, conducted an 

 experiment relative to injury due to flies in which two lots of seven 

 cows each were used. Lot No. 1 was kept during the day in a pad- 

 dock provided with shade trees, while lot No. 2 was protected from 

 flies by being kept in a screened stable. The cattle in both lots 

 were kept on the pasture during the night and taken off at 9 o'clock 

 in the morning. The experiment was continued for a period of 

 four weeks. The cattle in the lot protected from flies ate 835 pounds 

 more green corn than those that were unprotected. All the cows 

 lost in weight, but the protected cows lost nearly three times as 

 much as the others. In comparing the milk and butter production 

 of the first two weeks of the experiment with that of the two weeks 

 just preceding the experiment it was noted that there was a decrease 

 in both milk and butter. The milk reduction was greater for the 

 protected animals and the butter reduction was greater for the 

 unprotected animals. The conclusion reached was that the greater 

 amount of butter yielded by the protected lot was not sufficient to 

 pay for the increased trouble and expense entailed in stabling the 

 cows during the greater part of each day. 



Kent (1903), in an experiment at the Oregon Agricultural Col- 

 lege and Experiment Station, used a proprietary repellent on four 

 dairy cows. Four untreated cows served as controls. The treated 

 cows gained a total weight of 265 pounds while the untreated ones 

 gained 212 pounds. In comparing the milk and butter records of 

 two cows from each lot that were in about the same stage of lacta- 

 tion with the records of the same cows during the two months just 

 preceding the experiment it was found that the treated cows lost 

 about 10 per cent less than the cows not treated. 



Beach and Clark (1901), at Storrs Agricultural Experiment Sta- 

 tion, Conn., tested a proprietary fly repellent which the manufac- 

 turers claimed would effect a tremendous saving during the fly 

 season. The experiments covered a period of two seasons and the 

 cows were sprayed thoroughly once a day. The conclusions reached 

 by the authors are as follows: "1. The annoyance of cows by flies 

 seems to be overestimated. 2. Certain proprietary ointments known 



