Ticks and Mites 



3i 



parasite all the rest of their lives it does not affect 

 them seriously. These cattle are almost always 

 infected with ticks, and when taken north where 

 the ticks do not occur naturally and where the cat- 

 tle are therefore non-immune, some of the mature 

 ticks drop to the ground and lay their eggs which 

 in a few weeks hatch out and are ready to infect 

 any animal that passes by. The northern cattle 

 not being used to the disease soon sicken and die. 



It is estimated that the annual loss due to this 

 disease and the ravages of the tick in the United 

 States is over $100,000,000, so of course most 

 determined efforts are being made to stamp it out. 

 Formerly various devices for dipping the tick- 

 infested cattle into some solution that would kill 

 the ticks were resorted to, but it was always ex- 

 pensive and never very satisfactory. The immu- 

 nizing of the cattle by inoculating them when they 

 were young with infected blood has been practised. 

 Very recent investigations have shown that it is 

 possible and practicable to rid pastures of ticks 

 by a system of feed-lots and pasture rotation. The 

 aim is to have as many of the ticks as possible drop 

 to the ground on land where they may be destroyed 

 and to so regulate the use of the pasture that the 

 ticks in all of them may eventually be left to starve. 



Several similar diseases of cattle, many of them 



