RICKETS 641 



bers of vesicles or blisters between the toes and along the lower part 

 of the foot. There may also be some blisters in the mouth and on 

 the tongue. The presence of a similar condition in the cattle on 

 the premises is a valuable aid to diagnosis. 



Foot-and-mouth disease is a very dangerous and rapidly con- 

 tagious disease, and at the first signs of an outbreak State and 

 United States Government authorities should be notified, in order 

 that prompt steps may be taken to stamp out the infection before 

 it gets a foothold. 



RICKETS (RACHITIS) 



This is a disease in which there is a marked disturbance of 

 nutrition, and the animal is unable to properly develop bone tissue. 

 As a result, there is a lack of hardening of the bones, and marked 

 swellings and deformities take place. 



Rickets is especially common in pigs. It is also seen with con- 

 siderable frequency in young dogs. The disease is much more rare 

 in calves and foals. 



Causes. — This disease is one which is practically entirely due to 

 improper feeding. It occurs especially at about the age of weaning 

 and shortly thereafter. During the time when the pig is living on 

 the milk of the mother there is seldom any difficulty, unless the 

 diet of the sow be especially poor in those foods which aid in the 

 formation of bone tissue. In the breeds that develop very rapidly 

 after weaning this disease is especially frequent. 



The milk of sows is especially well supplied with the salts of 

 phosphorus and calcium. These salts are very important in the 

 development of bone in growing pigs. The pig must necessarily 

 have these large amounts of phosphorus and calcium in order to do 

 well. It is for this reason that they are liable to develop rickets 

 when weaned from the mother and placed on a diet that is poor in 

 these substances. 



When we have added to this improper diet a filthy, muddy feed 

 lot we have just the condition necessary for the development of 

 rickets. Growing animals cannot do well even with proper food 

 when placed in a filthy feed yard, and, when we have a combination 

 of the two, the little animals are bound to suffer. In the great hog- 

 producing belt of the Central West there is a tendency to feed large 

 amounts of corn, often to the exclusion of other articles of food. 



