Cattle Scab 325 



The itch gradually spreads along the back, sides, and 

 down on the outside of the legs. It does not seem to 

 occur on the inside of the legs, thighs, or the thin skin 

 of the abdomen. In its early stages, the coat looks 

 rough, the hair standing on end. The skin becomes 

 scurfy, and, a gummy exudation from it forms a crust 

 in the hair sometimes one -half an inch thick. The 

 hair then comes off, or is rubbed from the badly 

 affected areas, leaving bald patches of thickened, cal- 

 loused and wrinkled skin. These patches often show 

 first and most prominently on the top of the neck, which 

 looks like the neck of an ox that has been calloused 

 from wearing a yoke. 



After the hair comes off, the parasites leave the part, 

 the bald areas get well, and the hair starts to grow 

 again. Animals suffering from this disease have a de- 

 jected and debilitated appearance, and fall away rapidly 

 in flesh. They eat but little, and expend a considerable 

 amount of time and energy in licking and scratching 

 themselves. 



The itch spreads quite rapidly through a bunch of 

 cattle, especially if the general health of the animals is 

 not good. Six or eight weeks after the introduction of 

 an infested animal into a herd the disease is usually 

 thoroughly disseminated. Thrifty, vigorous animals 

 resist infestation much longer than others, and, when 

 attacked, recover much more quickly under treatment 

 than do unthrifty animals. The disease appears to 

 spread by direct contact of the infested with healthy 

 animals, the itch mites passing directly from one animal 

 to another. It is also spread by means of posts, feed- 



