308 SUMMER MANAGEMENT 



exudation dries a scab or crust is formed. Beneath this crust the 

 mites continue to irritate the skin and to multiply with great 

 rapidity. As they increase in numbers, they spread over the body 

 of the sheep until practically the whole of it is covered unless some 

 method is adopted to check them. The wool drops off where the scab 

 or crust forms, and the sheep presents a very haggard and sorry 

 appearance. But the disease ought to be detected long before this 

 stage is reached. 



The first symptom of scab is uneasiness caused by itching, which 



FIG. 195. Adult sheep tick. (From Kentucky Station Bulletin 143.) 



the sheep tries to allay by biting or pulling at the wool near the 

 affected spot and by rubbing. This scratching and rubbing against 

 posts, fences, and buildings will distribute many of the mites, which 

 adhere to the bits of scab and wool that have been rubbed off. It is 

 largely in this way that other individuals become infested. 



When scab is found in a flock the only thing to be done is to 

 dip the entire flock before the trouble has time to spread farther. 

 This work must be thoroughly done. Since many of the mites are 

 under the scabs, they are hard to reach with the dip unless the 

 scabs are first soaked or broken down by rubbing with some rough 

 object, such as a corn cob or piece of wood. One dipping is not 

 sufficient in that it does not destroy the eggs. After the first 

 dipping the sheep should be turned back into their pen, where they 



