26o 



disease first shows itself in dullness, loss of appe- 

 tite and a tendency to leave the herd and lie down 

 alone. A few days before these symptoms appear 

 the temperature rises from 103° to 107°. There is 

 little change in temperature until death or recov- 

 ery. 



Pathological Changes Observable After Death. — 

 The presence of small ticks on the udder or 

 escutcheon is a very important sign in herds north 

 of the Texas fever line. The watery condition of 

 the blood. The spleen or milt very much en- 

 larged, and filled with a blackish pulp. Enlarge- 

 ment of the liver, and its color changed to a 

 mahogany color. The distended gall-bladder, 

 caused by an excessive amount of bile in it. 



The Cattle Tick (Boophilus bovis) is the carrier 

 of this disease. Its life history is quite simple. It 

 is unable to come to maturity and reproduce its 

 kind unless it becomes attached to the skin of cattle, 

 whence it may obtain its food. The eggs laid on 

 the ground by the female tick after falling off the 

 cattle begin to develop at once. The time required 

 for hatching varies considerably, according to the 

 temperature. In the heat of summer about 13 days, 

 and in the fall, under the same conditions, from 

 four to six weeks. On pastures these little crea- 

 tures soon find their way on to cattle. They 

 attach themselves, by preference, to the tender skin 

 on the escutcheon, the inside of the thighs, and on 

 the base of the udder. When very numerous they 

 may be found on various parts of the body. They 

 remain clinging to the cattle until mature, and then 

 fall off and lay their eggs and hatch more new 

 ticks. 



How Prevention Is Possible. — The spread of 

 Texas fever can be prevented by two ways — sani- 



