326 DISEASES OF CATTLE, SHEEP, GOATS, ETC. 



Texas fever, they may also be injurious to cattle as external parasites. 

 While the power of transmitting Texas fever is undoubtedly the 

 most dangerous property possessed by the cattle tick and is the prin- 

 cipal cause for adopting stringent measures in securing its complete 

 eradication, nevertheless there still remain other good reasons for 

 the accomplishment of this achievement. These secondary objec- 

 tions 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 indefi- 

 nitely without causing any noticeable effect, but it is not uncom- 

 mon 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 causes more or less impoverishment 

 of the circulation. The animal must therefore be fed heavier in 

 order to meet the demands of the parasites in addition to the ordi- 

 nary needs of the host. If the ticks be removed from the body, the 

 bites inflicted are often distinguished by small inflamed or red- 

 dened areas somewhat swollen, with perforations of the skin which 

 may allow the entrance of various kinds of disease germs, and show- 

 ing that more or less irritation of the hide is produced by these para- 

 sites. This condition, together with the loss of blood, frequently in- 

 duces an irritable 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 weather, 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 ticks is not controlled, the cattle may be so re- 

 duced in condition that growth is retarded, and, in the case of young 

 animals, they may never become fully developed, but remain thin, 

 weak, and stunted a condition that has been termed tick poverty 

 and easily succumb to other diseases as a result of lowered vitality. 

 In milch cows this debilitating influence of the numerous ticks is 

 shown in a greatly reduced milk supply. This should not appear 

 strange when it is considered that some animals harbor several thou- 

 sand of these blood-sucking parasites. If these parasites are crushed, 

 it will be found that their intestines are completely filled with a 

 dark, thick mass of blood abstracted from the animal host and con- 

 taining nutriment that should go to the formation of milk, flesh, 

 and the laying on of fat. In some rare cases the large number of 

 bites over a limited area of skin may be followed by infection with 

 pus-producing organisms, giving rise to small abscesses which may 

 terminate in ulcers. The discharge from such sores, or in some cases 

 the mere oozing of blood serum through the incision made by the 

 mouth parts of the ticks, keeps the hair moist and matted together, 

 and the laying and hatching of fly eggs in these areas give rise to in- 

 festation with destructive maggots, causing ulcers and other compli- 

 cations that require medical treatment. These statements regarding 

 the secondary injurious effects of cattle ticks also apply to those ticks 

 which have been previously spoken of as harmless in so far as Texas 



