DOMESTIC ANIMALS 253 



Southern cattle are rendered im mune', or not subject to the 

 disease, by being exposed when young; but the fever kills during 

 the first summer most of the mature cattle carried from northern 

 to southern states. It is communicated by ticks dropped from 

 southern cattle carried north in the summer. Healthy herds 

 sicken and die if driven across the trail where infested herds 

 passed one, two, or three months before. 



Tick fever is a serious drawback to introducing improved 

 breeds in the South and has caused strict laws to be passed about 

 the summer marketing of southern cattle. The fever can be pre- 

 vented by cleaning cattle and pastures of ticks. They can be 

 removed from cattle by the use of kerosene and other oils. Pas- 

 tures can be cleaned by keeping cattle off an infected field for 

 several months, usually from the first of April till the first of 

 September. 



Cattle are inoculated against tick fever, just as people are against 

 smallpox. 



EXERCISE 



1. Are the cattle of your locality chiefly beef or dairy breeds ? Name 

 three points in proof of your statement. What breeds are most profit- 

 able in your section? Why? 



2. Make a balanced ration for a dairy cow, using corn, fodder, alfalfa, 

 and cotton-seed meal. 



3. A farmer raises corn and timothy hay. What should he sell and 

 what buy in order to furnish balanced rations for dairy cattle ? 



4. Take two milk bottles; wash and scald one and cool it with pure 

 water; rinse the other out with sour milk. Put sweet milk in both and 

 seal them. Open and examine at regular intervals. In which bottle 

 does milk sour first ? Why ? 



