REPELLENTS FOR PROTECTING ANIMALS FROM FLIES. 5 



as i fly removers ' will protect the animal to a greater or less extent, 

 but their use has little or no effect on the milk or butterf at secre- 

 tion." 



Eckles (1905) carried on experiments for two seasons at the Mis- 

 souri Agricultural Experiment Station with a proprietary repel- 

 lent for the purpose of determining whether the use of a repellent 

 on dairy cows would have any influence on the amount of milk and 

 butter produced. During the first season 16 cows were used and 

 during the second season 22 cows were used. The fly season was 

 divided into periods of two weeks, and the herd was sprayed each 

 morning during alternate periods. A comparison was made be- 

 tween the sprayed and unsprayed periods. The conclusion reached 

 by the author was that the use of the fly repellent was fairly effec- 

 tive in preventing the annoyance from flies if applied every morn- 

 ing, but that the yield of milk and fat was not appreciably affected 

 by its use. The only advantage observed was that the cows stood 

 more quietly during milking. With regard to the shrinkage in 

 milk production during hot weather, the author has the following 

 to say: "The rapid shrinkage that occurs in the yield of a cow 

 during the hottest summer months is a well-established fact, but is 

 probably not so much on account of flies as to failure to graze suffi- 

 ciently, if on pasture, on account of the heat." 



THE INFLUENCE OF COLOR ON FLIES. 



Several years ago Dr. Schroeder, of the Bureau of Animal In- 

 dustry, called my attention to some pictures of Holstein cattle he 

 had taken in connection with some tuberculosis work, in which the 

 flies on the animals were confined almost exclusively to the black- 

 colored spots. Beach and Clark (1904) state that some animals 

 suffer more from hornflies than others and that dark-colored animals 

 suffer more than light-colored ones. Marlatt (1910) states that the 

 hornfly exhibits a certain preference for red or other dark-colored 

 cattle, and that such animals are more thickly infested has been 

 frequently noted. He states, however, that when the flies are abun- 

 dant this preference is not so strongly marked. 



Marre (1908) refers to a discovery which a farmer in the vicinity 

 of St. Cyr made relative to the influence of color on flies. The 

 farmer had 170 cows in a number of stables and noted that flies had 

 a marked aversion for blue. The idea came to him to add blue to 

 the whitewash with which he coated the walls of his buildings each 

 year. After doing this the flies left his cattle stables. 



The formula used for the wash is as follows : 



Water 100 liters (105.6 quarts, or 26.4 gallons). 



Lime (slaked) 5 kilos (11 pounds). 



Ultramarine blue 500 grams (1.1 pounds). 



