THE ANIMAL PAEASITES OF CATTLE. 529 



About 10 species of ticks have been reported as parasites of cattle 

 in the United States. The most common and the most important is 

 the species known as Margaropus annvlatits, which transmits Texas 

 fever. Information concerning this tick and Texas fever has been 

 given elseAvhere in this volmne (p. -180). 



The ear tick {Ornithodoros megnini) is frequently found in the 

 ears of cattle in the western United States. 



TreatTnent for ear ticks. — On account of their protected location 

 ear ticks are not affected by dipping or spraying. Ear ticks are very 

 difficult to kill, and remedies strong enough for this purpose are 

 liable to injure the cattle, but the parasites may be expelled by pour- 

 ing into the ear noninjurious substances such as cotton-seed oil, lin- 

 seed oil, 20 per cent emulsion of crude petroleum, or almost any stock 

 dip diluted as for use in dipping. Some stock owners report favor- 

 able results from the use of arsenical dip (see p. 504). 



BLOODSrCKERS OR LEECHES. 



These worms are sometimes taken up by cattle when drinking from 

 ponds. They may attach themselves to the inner surface of the 

 mouth or nose, and sometimes reach the upper part of the windpipe 

 or of the gullet. Bleeding at the mouth or nose may be noticed, the 

 membranes where the leech is attached are liable to be swollen and 

 congested, and as a result of the loss of blood a condition of anemia 

 may result. 



Treatment for bloodsuckers. — If the worm can be reached it may 

 be destroyed by cutting it in two with a pair of scissors, or it may 

 be removed with forceps or with the fingers after wrapping a towel 

 around the hand so that the worm can be held without slipping. 

 Fumigation with tobacco or tar may cause the worm to release its 

 hold if it can not be removed by other means. Ponds may be rid of 

 infestation with bloodsuckers by the introduction of eels. 



PARASITES or THE STOMACH. 



The stomach of cattle consists of four compartments, of which the 

 first and fourth are most likely to be the seat of parasitic infestation. 

 The first stomach, or paunch, contains large numbers of minute para- 

 sites known as protozoa, which are too small to be seen with the 



^ For a more complete discussion consult Farmers" Bulletins 258 and 378, Bulletin 130 

 of the Bureau of Animal Industry, and Bulletins 15, technical series, and 72 of the Bureau 

 of Entomologrj', all issued by the United States Department of Agriculture. 

 16923°— 12 34 



