STERILITY 165 



examples may be mentioned chronic endometritis, atrophy, 

 degeneration and aplasia of the testicles or ovaries. Exces- 

 sive sexual use, especially when the animals are young, and 

 long-continued masturbation are causes. Often the cause is 

 purely psychic. For instance, many jacks refuse to cover 

 mares, although jennets are served with promptness. Zebra 

 stallions will rarely copulate in the presence of persons, 

 although if left alone with the female the coital act is promptly 

 committed. 



Treatment. — Diminished sexual desire should not be con- 

 fused with impotency or sterility, although it may be a cause 

 of these. The food and care of the animal should be looked 

 after and any apparent discrepancies in these factors removed. 

 If the patient is overfat curtailing the food ration, allowing 

 greater quantities of protein and plenty of exercise may over- 

 come the condition. Some male animals which have been 

 kept isolated or away from females for a long time seem to 

 lose the sexual habit. Very young stallions which have never 

 covered a mare must sometimes be encouraged and stimu- 

 lated to perform the coital act. Jacks which refuse to serve 

 mares can often be stimulated sexually by allowing them to 

 smell the urine from a jennet in heat or sometimes even by 

 holding a jennet where they can see her while approaching 

 or teasing the mare to be served. Certain drugs (aphrodis- 

 iacs) will stimulate sexual desire. Cantharides (cows 5j> 

 mares 3ss; or the tincture, cattle 3v and mares 3 iisa) has 

 long been employed as an agent to promote sexual desire. 

 Of late Yohimbin, used subeutaneously, is recommended. 

 Its cost makes it almost prohibitive for veterinary use. 



STERILITY. 



Definition. — By the term sterility we understand that the 

 female animal is barren or unable to produce young. 



Occurrence. — Sterility is very common, especially among 

 well-bred cows, and obviously attains great economic impor- 

 tance. 



-Etiology. — Sterility is a symptom and not a disease. It 

 can have, therefore, a great many causes. To go into these in 



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