Texas Fever 375 



tion of the arsenical solutions for dipping cattle has 

 enabled the various states with the assistance of the 

 federal government to free large areas completely of 

 ticks. One attack of Texas fever gives immunity, and 

 young calves are not so susceptible to the disease as are 

 older animals. It is probable that the reason that 

 southern cattle do not have Texas fever is because their 

 immunity was acquired as very young calves at an age 

 when they do not seem to be seriously affected by the 

 disease. The older the animal the more serious is the 

 fever as a rule. 



The Missouri and Texas Experiment Stations have 

 devised a method of conferring immunity on susceptible 

 cattle intended for shipment into permanently infected 

 territory. It is by injecting serum obtained from the 

 blood of immune cattle, and is very successful. Cattle 

 intended for such shipments should be young, and 

 should be taken in the. fall, when the ticks are not so 

 numerous and the weather is cool. 



When an "outbreak of Texas fever occurs, there is 

 no danger to cattle in the surrounding territory, pro- 

 vided they are kept ofE infested ground. It is com- 

 monly said by stockmen that "a wire fence will stop 

 the spread of Texas fever," but it is safer to put a 

 greater barrier, in the way of distance, as the young 

 ticks may be washed short distances, or cattle may 

 break through a fence and carry the ticks. After 

 an outbreak of Texas fever, no susceptible cattle 

 should be allowed on the infested pasture or quar- 

 ters until the ticks have been destroyed by the cold of 

 winter. 



