SHEEP TICK AND ITS EEADICATION BY DIPPING. 13 



of the active principle, all have an important bearing on the results. 

 Other factors being equal, the dip that remains longest in the wool 

 and retains its killing power for the longest period is most desirable, 

 not only for destroying the parasites on the animal but also for 

 preventing reinfestation. 



In dipping sheep for ticks the entire flock, together with all goats, 

 dogs, or other animals which may have been with the sheep, should 

 be dipped regardless of the number showing infestation. The fleece 

 should be saturated thoroughly, but as there are no crusts or scabs 

 to be penetrated, it is not necessary to hold the animals in the vat 

 longer than about 1 minute. The head of each animal should be 

 submerged at least once and care taken that every part of the fleece 

 is wet. As only coarse-wool and medium-wool sheep usually become 

 infested heavily, and as such fleeces are penetrated easily by the dip, 

 it is not considered necessary to maintain the dip at a high tem- 

 perature. How^ever, it should not be cold enough to chill the ani- 

 mals; the range should be between a minimum of 65° F. and a maxi- 

 mum of 95° F. The temperature of the dip should be ascertained 

 accurately by using a thermometer. If a proprietary dip is used the 

 printed instructions on the label of the container should be followed 

 both as to the time the animals are to be held in the dip and the 

 temperature at which the dip is to be used. 



The season best suited for dipping to eradicate ticks depends upon 

 the altitude, the climatic conditions, and the methods of handling 

 the sheep. In those sections where spring shearing is practiced, 

 July and August are considered the best months for dipping. If 

 the lambs become heavily infested shortly after shearing, which often 

 occurs, the flock should be dipped as soon as the shear cuts heal. 

 One objection to dipping too soon after shearing is that the wool is 

 short and the fleece will not retain much of the dip. For this reason 

 fall dipping probably would prove more effective than summer 

 dipping in eradicating ticks. It is advisable, however, to dip at 

 about the same time that the neighboring flocks are dipped in order 

 to lessen the chances of reinfesting the neighborhood. 



If the dipping is to be successful, it is necessary to give close atten- 

 tion to the details and to see that the work is performed carefully and 

 thoroughly. Sheep should not be dipped immediately after shearing; 

 a period of at least lOclays should elapse between shearing and dip- 

 ping, in order that the shear cuts may heal. It is dangerous to dip 

 sheep in some of the dipping preparations if there are any fresh 

 wounds on the animals ; consequently, dogs that bite the sheep should 

 not be allowed in the dipping corrals. The chutes, pens, and dipping 

 vat should be examined closely for nails, broken boards, or any object 

 that may puncture or wound the skin of the sheep. Animals having 

 fresh wounds when dipped in some of the dips usually develop a 



