482 DISEASES OF CATTLE. 



eggs in the northern pastures. After hatching, the young ticks would 

 soon get upon any northern cattle which happened to be on the pas- 

 ture. So soon as they attached themsehes to the skin they inocu- 

 lated the cattle, and Texas fever would break out a week or more 

 thereafter. For many years there had been a growing suspicion that 

 the cattle tick was in some way concerned in the spread of Texas 

 fever, and the facts which snipported this supposition finally became 

 so numerous and convincing that a series of experiments was inaugu- 

 rated by the Bureau of Animal Industry which served to show that 

 the tick is abundantly able to carry the disease to a herd of healthy 

 cattle, and, in fact, is probably the only agent concerned in the trans- 

 mission of the disease from southern cattle to susceptible northern 

 animals. 



InjuHous effects of cattle ti-cks. — Unfortunately man}'^ cattle owners 

 who have alwa3^s been accustomed to see both ticks and ticky cattle 

 on their farms are not inclined to attach much importance to these 

 parasites, and, as a rule, through lack of appreciation of their dam- 

 aging effects, placidly consider them as of little consequence. That 

 ticks may be detrimental to their hosts in several ways has probably 

 not suggested itself to these stockmen, who are most vitally affected, 

 and it therefore seems necessary to emphasize the fact that, in ad- 

 dition to their relation to Texas fever, they may also be injurious 

 to cattle as external parasites. While the power of transmitting 

 Texas fever is imdoubtedly the most dangerous property possessed 

 by the cattle tick and is the principal cause for adopting stringent 

 measures looking to its complete eradication, nevertheless there still 

 remain other good reasons for the accomplishment of this achieve- 

 ment. These secondary objections to the presence of ticks on cattle 

 consists in the physical harm they do to the host aside from the pro- 

 duction of the specific disease of Texas fever. True, a few parasites 

 may remain on cattle indefinitely without causing any noticeable 

 effect, but it is not uncommon to notice bovine animals on pastures 

 with their hides heavily infested with these pests. In such cases it 

 can readily be seen that the continuous sucking of blood cau.'^s more 

 or less impoverishment of the circulation. The animal must there- 

 fore be fed more in order to meet the demands of the parasites in 

 addition to the ordinary needs of the host. If the ticks are removed 

 from the body, the bites inflicted are often distinguished by small, 

 inflamed or reddened areas somewhat swollen, with perforations of 

 the skin which may allow the entrance of various kinds of disease 

 germs, and showing that more or less irritation of the hide is pro- 

 duced by these parasites. This condition, together with the loss of 

 blood, frequently induces an irritable state and evidence of uneasiness 

 commonly known as " tick worry," which results in the loss of energy 

 and other derangements of the animal's health. It may in some cases, 



