the Pyrenone concentrate was diluted with 9 parts of water; cows in the first of these three groups were 

 sprayed three times a week, each time with one-fourth pint per animal; those in the second, twice weekly, 

 each time with one-fourth to one-half pint per animal; and those in the third, once a week, each time with 

 four -fifths pint to 1^ pints per animal. 



Light applications of the concentrate made at frequent intervals gave the most effective control; 

 control was best and the least material was used when light applications, each of 1 to 2 milliliters (about 

 1/30 to 1/15 ounce) per cow, were made twice dadly. The amount of spray used was just enough to dampen 

 the ends of the hairs on the backs and sides of animals. Good control was obtained when sprays were 

 applied daily, three times a week, or twice a week. 



Most dairymen who used the concentrate spray preferred it to dilute sprays. The concentrate was 

 applied in small quantities with inexpensive, hand-operated, atomizing sprayers. Used as directed, it did 

 not gum the hair or burn the hides of animals. One exhibitor of dairy cattle believed that the concentrate 

 spray he used was largely responsible for keeping the hair of his show animals in good condition. 



GAINS FROM HORSE FLY CONTROL ON DAIRY CATTLE 



Southern Illinois farmers queried early in 1950 about the effect of horse flies on dairy cattle esti- 

 mated that the pests were responsible for milk production losses ranging from 25 to 40 per cent. One 

 dairyman stated that in some summers, when horse flies were unusually numerous, his milk cows became 

 nearly dry during the fly season and were unable to return to their previous production levels even after 

 the flies disappeared. Several years ago, C. W. Howard, an entomologist working in another state, found 

 that sustained attack by horse flies reduced milk production 66 per cent in 2 weeks and nearly 100 per cent 

 in 3 weeks. Under attack by horse flies, animals suffer not only from loss of blood but from loss of graz 

 ing time and energy, which they dissipate in attempts to evade their pain-inflicting enemies. 



To measure gains resulting from horse fly control on dairy cattle, experiments were established 

 involving 25 southern Illinois herds (293 cows) in the summer of 1950. Twelve of the herds were treated 

 with Pyrenone concentrate or with emulsions containing not less than 1.0 per cent piperonyl butoxide and 

 0.1 per cent pjnrethrins. Excellent tabanid control was obtained. Of the other 13 herds, used as checks, 6 

 were treated with DDT, 5 with methoxychlor, and 2 with repellent sprays. The DDT and the methoxychlcr 

 were used primarily to eliminate horn flies. 



The experiment extended through four successive test periods of 30 days each. Treatment was 

 started J\me 29, at the end of the second period, and continued through the fourth period. Butterfat produc- 

 tion records were used to measure the effect of tabanid control. Production of butterfat in treated herds 



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