PARASITES AND PARASITIC DISEASES OF HORSES 



51 



The head of each animal should be completely submerged for 

 an instant at least once while in the vat. The head should not 

 be held under, but quickly ducked with a dipping fork and re- 

 leased. Two duckings 

 of the head are ad- 

 visable, especially if 

 the animals are af- 

 fected with scabies. 

 Care should be taken 

 to see that the inner 

 surface of the ear is 

 well soaked. 



In dipping for lice 

 it is not necessary to 

 hold horses in the vat, 

 but if they h a v e 

 scabies they should be 

 held in the vat two or 

 three minutes. After 

 leaving the vat the 

 animals should be held 

 in the draining pens 

 until all surplus dip 

 has drained off their 

 bodies. (Fig. 34.) 

 Dipping should be fin- 

 ished for the day early 

 enough to dry the ani- 

 mals before sunset. 



Before approving a 

 dip for use in official 

 dipping one of the re- 

 quirements of the Bu- 

 reau of Animal In- 

 dustry is that there 

 shall be a practical 

 field test for such dip. 

 Of the various classes 

 of dips used on horses, 

 three only are on the 

 approved list — arseni- 

 cals, lime-sulphur, and nicotine. Of these the two most commonly 

 used are the lime-sulphur dip for mange and the arsenical dip for 

 lice and ticks. 



Figure 34. — Exit incline and draining pens of horse- 

 dipping vat 



ARSENICAL DIP 



Arsenical dip, when properly used, eradicates biting and sucking 

 lice, but it is not an effective remedy for mange. Prepared arsenical 

 dips have been placed on the market, but those which are permitted 

 by the Government for use in dipping cattle for southern fever ticks 

 are suitable for use in dipping horses, mules, and asses for lice. The 

 instructions on the label of the container should be followed in diluting 



