128 



VETERINARY STUDIES 



Fig. 



43. — Sheep Tick and Enlarged 

 Proboscis. 



entire life history is passed on the sheep host. The mature 

 tick pierces the skiu in order to suck blood, thus causing serious 

 irritation and unthrift. 



The treatment commonly used is coal tar dip, 2 or 3 per cent 

 applied after shearing. The wool must be stored where the 

 dipped sheep cannot become reinfected from it. 



Dipping should be repeated in from twenty to forty days 

 depending on the weather. Lambs must be protected during 



shearing time, otherwise 

 the ticks will leave the older 

 sheep and go to the lambs. 

 Sheds, pens, etc., must be 

 cleaned and disinfected a.s 

 for lice. 



Ticks. — True ticks are 

 temporary parasites, com- 

 monly found in brush and 

 tall grass. 



Life History. — The j'oung 

 female crawls up on brush 

 or grass or weeds and 

 waits for some animal to 

 come along and brush her 

 off. She soon attaches to the skin, gorges with blood, and 

 drops off. After a few days, she begins laj'ing several thousand 

 eggs and dies soon afterward. The eggs hatch in 15 to 20 days 

 if conditions are favorable. 



Treatment. — Any safe oily preparation may be used to de- 

 stroy the common ticks. (See Texas Fever for dipping.) 



Ringworm. — This disease appears most commonly on the heads 

 and necks of cattle, especially calves; but man and all domestic 

 animals are also subject to it. It is caused by a vegetable para- 

 site (Trichopliyton) growing in the skin, somewhat like mil- 

 dew in a grape leaf. This disease appears in the form of round, 

 raised, and bald patches, especially on the heads and necks of 

 calves during the winter. The patches are scaly or crusty, an 

 inch or two across; the hairs stand erect, then split and break. 

 There are usually several such patches close together. Ring- 

 worm spreads readily by inoculation. It is not especially seri- 

 ous; but it is disagreeable. 



A good method of treating ringworm is to use scrubbing 



Melophagus ovinus. Properly a sheep 

 louse. 



