LICKING DISEASE— PICA— ALLOTBIOPHAOY 187 



impotency in the male. In these cases it assumes economic 

 importance and requires treatment. 



Treatment. — Treatment consists in reducing the quantity 

 and character of the food and allowing the animal plenty of 

 exercise. Foods containing large amounts of carbohydrates 

 and fats should be fed sparingly, while those consisting largely 

 of protein may be allowed. Thyroid gland preparations are 

 recommended as idiothyrin (gr. x-xx)., 



LICKING DISEASE. PICA. ALLOTRIOPHAGY. 



Definition. — Licking disease or pica is a perversion of the 

 appetite manifested by a craving for unnatural food. The 

 afflicted animals will lick, gnaw and even eat objects which 

 they would not touch in health. Associated with the symp- 

 toms of perverted appetite are nervous nutritive disturbances. 



Occurrence. — Licking disease is usually confined to localities 

 or even certain premises. It may sometimes occur enzootic- s 

 ally. It is most commonly seen among cattle which are kept 

 stabled continuously and appears especially during the winter 

 months. It is therefore more common in Europe than in 

 America. Pica is sometimes a forerunner of osteomalacia. 



Etiology. — The causes of pica are not known. In some out- 

 breaks it has been shown to be due to spoiled forage and there- 

 fore a form of forage poisoning. As pica is so frequently 

 associated with osteomalacia in all probability it may have 

 the same causes and may be the prodromal stage of the same 

 disease. 



Symptoms. — The first symptoms are those of indigestion. 

 The appetite is impaired, rumination suppressed and the 

 patient is constipated. The symptoms of perverted appetite 

 begin gradually, the cattle licking the walls, partitions and 

 even the floor of the stable almost continuously. In some cases 

 they gnaw or swallow objects of various nature, including 

 indigestible and often loathsome things. Soon the patients 

 begin to lose weight, grow thin and eventually emaciate. 

 Finally they become cachectic and usually die in a few months. 



Course and Prognosis.— The course is chronic with exacerba- 

 tions and remissions extending over several months. If the 



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