480 IOWA DEPARTMENT OF AGRICULTURE. 



The hoof of a sheep suffering from a chronic case of foot-rot grows out 

 rapidly and becomes very hard. It will often be found with the toes so 

 thickened and lengthened that the front part of the foot is raised above 

 its natural incline and the tendons at the heel are subjected to addi- 

 tional strain, all of which tends to increase the lameness and the 

 awkwardness in gait of the victim. These thickened and elongated toes 

 will frequently be seen to have attained an added length of 3 or even 4 

 inches, and they curl up like sled runners, greatly interfering with the 

 progression of the animal. 



The sheep finds the act of walking so painful when the disease has 

 become thoroughly established that it remains quietly lying in some 

 secluded corner or, if diseased in the forefeet only, crawls around on its 

 knees In its effort to keep with the remainder of the flock or to get within 

 reach of its food. Its temperature rises until there is evidence of con- 

 siderable fever. The appetite is seriously impaired and the patient rap- 

 idly loses condition and weight. 



During warm weather there is great danger of an attack by maggots 

 as soon as the lesions are discharging freely, and unless these are quickly 

 removed they will appear in such numbers as to rapidly bring the course 

 of the disease to a fatal ending. They not only invade the affected feet, 

 but will also locate at any point of the body at which the wool has 

 become suflSciently contaminated by the purulent discharge from the 

 ulcerous tracts to afford them a suitably moistened breeding place. The 

 wool on the sides of the body is frequently more or less soiled from con- 

 tact with the diseased feet while the animal is lying down, and it is in 

 such areas that the fly deposits the eggs that hatch into destructive 

 larvae. As soon as the maggots are hatched they begin to burrow into 

 the tissues upon which they are located and they quickly perforate the 

 skin of their host, thus causing complications which bring its suffering 

 to a close. 



COURSE AND SUSCEPTIBILITY. 



The course of this disease is slow and protracted, usually starting 

 with one foot and subsequently involving one or more of the others. 

 During this interval it would probably have likewise spread to the feet 

 of other sheep, and in this way the disease may remain for several months 

 in each member of the flock and for eight or ten months in the flock 

 itself. When the ulcerous processes have become advanced and aggra- 

 vated, fever develops, the appetite is lost, and the animal grows so 

 emaciated that deam intervenes. In some cases that are left untreated 

 recovery may follow slowly, but there is usually either a dense fungoid 

 growth between the claws, a stiffening of the joints of the ankle, or a long 

 fissured and misshapen hoof. When treatment is properly applied in the 

 early stages of the disease it is usually cured within ten days. It is 

 very rare for death to occur as a result of foot-rot, although in very 

 virulent outbreaks involving 3 or 4 feet of each sheep the affection may 

 terminate fatally within two or three months. 



The course of the disease is also dependent upon the susceptibility of 

 the affected animal. Thus it is a well-accepted fact that the pure breeds 

 of fine-wooled sheep are especially susceptible to foot-rot, although the 



