488 DISEASES OF CATTLE. 



or more thereafter. For many years there had been a growing 

 suspicion that the cattle tick was in some w^ay concerned in the 

 spread of Texas fever, and the facts which supported tliis suppo- 

 sition finally became so numerous and convincing that a series of 

 experiments was inaugurated by the Bureau of Animal Industry 

 which served to show that the tick is abundantly able to carry the 

 disease to a herd of health cattle, and in fact is probably the only 

 agent concerned in the transmission of the disease from southern 

 cattle to susceptible northern animals. 



INJtJBIorS EFFECTS OF CATTLE TICKS. 



Many cattle owners who have always been accustomed to see both 

 ticks and ticky cattle on their farms are unfortimately not inclined 

 to attach much importance to cattle ticks, and, as a rale, through 

 lack of appreciation of their damaging 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 there fore seems necessary to 

 emphasize the fact that, in addition to their relation to Texas fever, 

 they may also be injurious to cattje as external parasites. Wliile 

 the power of transmitting Texas fever is undoubtedly the most dan- 

 gerous property possessed by the cattle tick and is the principal 

 cause for adopting stringent mea^jures in securing its complete eradi- 

 cation, nevertheless there still remain other good reasons for the 

 accomplishment of this achievement. These secondary objections to 

 the presence of ticks on cattle consist in the physical harm they do 

 to the host aside from the production 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 pastui-es with their hides heavily infested 

 with these pests. In such cases it can i-eadily be seen that the contin- 

 uous sucking of blood causes more or less impoverishment of the cir- 

 culation. The animal must therefore be fed heavier in order to 

 meet the demands of the parasites in addition to the ordinary needs 

 of the host. If the ticks be removed from the body, the bites inflicted 

 are often distinguished by small inflamed or reddened areas some- 

 what 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 produced by these parasites. This 

 condition, together with the loss of blood, frequently induces an irri- 

 table state and evidences 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 become so pronounced, 

 especially in hot w-eather, that the animal will lose flesh in spite of 

 good pasturing, thereby reducing the vitality and rendering it more 

 susceptible to the inroads of disease. Moreover, if the infestation of 



