EFFECT OF CATTLE TICK ON MILK PRODUCTION. 3 



period. The body weights were taken for 10 consecutive days at 

 the beginning of the work; thence once every 10 days until the last 

 period, when they were taken for 10 consecutive days as at the 

 beginning of the work. The weights were taken at about the same 

 hour and under the same conditions each time, so that the extent 

 of fill, both as regards feed and water, would be similar. The treat- 

 ment of the two groups in all respects other than ticks was as nearly 

 alike as possible. 



FEEDING. 



The tick-free group of cattle were fed as much alfalfa hay as they 

 would eat readily, and enough corn chop, wheat bran, and cottonseed 

 meal, mixed in the proportions 4 : 2 : 1, to maintain the body weights. 

 The aim was to give the infested group the same kind and amount 

 of feed, but toward the close of the experimental period these cows 

 failed to consume as much hay as the tick-free cows. In order to 

 make the digestible nutrients consumed practically equal for each 

 group, the grain ration of the infested cows was raised 1 pound for 

 each 2\ pounds of hay refused. Both groups of cows had access 

 to salt and water in unlimited quantities. 



THE TICKS. 



The seed ticks used to obtain the various degrees of infestation in 

 the cattle were the progeny of mature ticks obtained from several 

 sources. The supply of ticks was secured through the cooperation 

 of Dr. Charles F. Dawson, of the Florida State Board of Health, as 

 the local supply was insufficient. Dr. Dawson's first material was 

 collected from Tallahassee, Kissimee, Dade City, and other places in 

 Florida. A few small lots were received subsequently. The earlier 

 adult ticks were collected between April 13 and April 28. The seed 

 ticks or larvas from eggs laid by these emerged between May 22 and 

 June 2, following. On June 12 and 14 two other consignments were 

 received. The resulting broods seemed sufficient to insure thorough 

 infestation of the cattle during the first weeks of the experiment. 



A second source of seed ticks was the Anthony Farm cattle 

 not under test. This supply, together with that already mentioned, 

 was sufficient to last until the middle of July by applying them but 

 once a week. These two sources of supply proved to be insufficient, 

 and a third lot was obtained from the Zoological Division of the Bureau 

 of Animal Industry. These were mainly a portion of the original col- 

 lection by Dr. Dawson, which had been sent by him to Washington and 

 intended for another purpose. One flask of specimens labeled as 

 originating in Texas accompanied these. This Washington consign- 

 ment was applied during July. As fast as the ticks matured on the 



