DISEASES OF ANIMALS 



147 



where sheep have been dipped by their 

 owners this has been done without caus- 

 ing any injury. 



The chief objections which have been 

 raised against different sheep dips are 

 their injurious effect upon the sheep or 

 upon the color or staple of the wool. An 

 extensive investigation of this matter 

 was made by Hollings in Bradford, Eng- 

 land, from the standpoint of the quality 

 of the wool. Many complaints have 

 been made by wool buyers of injuries to 

 wool from different kinds of dips. The 

 investigations in question cover nearly 

 all of the English colonies. It appeared 

 that as a rule the low price paid for 

 inferior grades of wool was due to the 

 injury from the different dips. Hol- 

 lings condemns lime and sulphur dip as 



alkali or arsenic be present in the dip 

 great harm results to the wool. On this 

 account the use of arsenical dips can 

 hardly be recommended as a general 

 farm practice, since mistakes might 

 easily be made in compounding the dip. 

 As a matter of fact the injury to the 

 wool from the use of lime and sulphur 

 dips has caused exceedingly few com- 

 plaints in this country and it is recom- 

 mended as the best dip not only for 

 effectiveness in curing scab but for ease 

 in preparation and application and com- 

 parative harmlessness to the sheep and 

 wool. 



Head scab — This disease is also 

 caused by a parasitic mite (Sarcoptes 

 scabiei oris). Other varieties of this 

 mite cause itch or mange in other farm 



Fig. 105 — SECTION OF DIPPING VAT SEEN FROM THE SIDE 



injurious. It was claimed to cause 

 trouble in scouring, dyeing and weaving 

 of the wool and for this reason has been 

 abandoned by many sheep raisers in 

 Australia, Tasmania, and Argentine Re- 

 public. Tobacco dips were found to 

 stain the wool in large percentages of 

 cases except where sheep were dipped 

 immediately after shearing. Tobacco 

 dips are further objected to on the 

 ground that they are injurious to the 



Fig. 106 SMALL DRIPPING CHUTE, WITH 



TROUGH AT END TO CATCH DRIP 



sheep. Carbolic dips, and especially 

 those containing pitch oil, are injurious 

 to the wool staple. Hollings believes as 

 a result of his investigations that ar- 

 senical dips are effective in curing scab 

 and that these dips cause the least in- 

 jury to wool when properly prepared and 

 applied. If, however, an excess of either 



animals, producing similar diseases upon 

 them. The attacks of the mite are 

 largely confined to the head and this 

 gives rise to the common name for the 

 disease. The mange caused by the head 

 scab mite may extend backward about 

 the eyes, ears and neck. The mites 

 burrow under the skin of parts not 

 heavily covered with wool, causing the 

 formation of pustules, which become in- 

 crusted. Any of the dips commonly 

 used in the treatment of scab will cure 

 this form of scab and the cure takes 

 place promptly with the remedies ap- 

 plied in other stages of the disease. 

 The crusts may first be removed by rub- 

 bing with oil, after which, if other dips 

 are not convenient, kerosene emulsion or 

 a tar sulphur oil ointment will give 

 satisfactory results. 



Botfly_The sheep botfly (Oestrus 

 ovis) lays its eggs in the nostrils of the 

 sheep in early summer and the eggs, up- 

 on hatching, develop into grubs which 

 penetrate deeply into the nasal cavity 

 and after becoming full grown fall to the 

 ground where they bury themselves and 

 finally emerge as adult flies. The flies 

 somewhat resemble the common house 

 fly but are covered with small round 

 spots and the abdomen bears velvety 



