DISEASES OF CATTLE 331 



be board-tight at the bottom to prevent ticks from crawling out, and 

 there should be a 10-foot space between the two lines so that the ticks 

 would be unable to crawl across to the opposite pasture if they should 

 perchance get out. One of these pastures is then kept free from 

 cattle, horses, mules, and asses from spring to late fall, or, better, 

 until January. By this time it will be free of ticks and ready for 

 tick-free cattle that have been cleaned by any of the methods above 

 described; then the other pasture is abandoned for the same period 

 of time. 



Butler states that the pasture may be kept free of ticky animals 

 for a shorter period with equally beneficial results, and recommends 

 the following method : 



The tick-infested cattle should be removed from their pasture 

 on September 1, cleaned of ticks by any of the methods previously 

 mentioned, and placed in a cultivated field or pasture where no 

 ticky animals have been for at least six months and where they can 

 not come in contact with ticky animals or ticky soil. The original 

 pasture should not be restocked until the following spring (April), 

 at which time all the eggs laid there before September 1 will have 

 hatched, the seed ticks will have starved, and the pasture will be free 

 of ticks. It may then be used for cattle that have no ticks upon 

 them. In case the cattle are not free of ticks when placed in the cul- 

 tivated field or noninfested pasture on September 1, they will infect 

 this field and will carry ticks to the original pasture if placed there 

 in the spring. 



By Cultivation. Another method of destroying ticks on pas- 

 tures is to cultivate the soil for a year without permitting any ticky 

 cattle, horses, or mules on the ground during this period. After this 

 treatment the field will be without any Texas-fever ticks and may be 

 restocked with cattle not infested with these parasites. 



By Burning Off the Grass. Pastures that are too large to be 

 disinfected by the above measures or those grazing lands that are 

 open and can not be inclosed, or ranches where a division of the pas- 

 ture is impracticable, may be freed from ticks by burning them off 

 in the spring or fall and then keeping tick-infested animals from 

 the land. It is advisable to burn off the grass in the spring when 

 practicable, as this permits the pasture to recover quickly and to 

 supply feed in several weeks. 



How to Free Cattle and Pastures of Ticks at the Same Time. 

 The feed-lot method has been recently recommended by Mor- 

 gan after conducting field experiments in Louisiana and has for its 

 object the ridding at the same time of pastures and cattle of the fever 

 tick. This plan, like the "soiling" method, suggested by Curtice, 

 is based upon the length of time the tick lives upon cattle and the 

 period required for the eggs to be laid and hatched and the seed 

 ticks to attach themselves to their host. For carrying out this idea 

 take a field which has been sown to corn, millet, sorghum, or other 

 forage and fence off three lots within such a field, in one of which 

 the ticky cattle are placed on June 1 by removal from their custom- 



