THE ANIMAL PARASITES OF CATTLE. 505 



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

 ears of cattle in the western United States. 



Treatment 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, 

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

 stock dip diluted as for use in dipping. 



BLOODSUCKERS 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 cut- 

 ting it in two with a pair of scissors, or it 

 may be removed with forceps or with the fin- 

 gers after wrapping a towel around the hand so 

 that the worm can be held without slipping. fig. u. -Portion of the wail of 

 Fumigation with tobacco or tar may cause the first stomach with eon- 

 the worm to release its hold if it can not ^Ll^ ,^7^ 

 be removed by other means. Ponds may 

 be rid of infestation with bloodsuckers by the introduction of eels. 



PARASITES OP 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 

 naked eye. These small organisms apparently are in no way injuri- 

 ous. A species of fluke (Paramphistomum cervi) is occasionally 

 found in North American cattle, especially grass-fed cattle, attached 

 to the inner surface of the first stomach (fig. 14). This worm is about 

 one-half inch long, and somewhat conical in shape, hence the name, 

 conical fluke, by which it is sometimes known. Although this 

 parasite has been accused of producing serious effects, it is generally 

 considered harmless. 



Several species of roundworms may occur in the fourth stomach. 

 Two of these are of special importance. 



