Persistent Hymen

The mare in this write up was presented because the stallion was having a difficult time breeding her.  She would come into heat and be ready to accept the stallion but he could not breed her.  During phone conversations with the clients we discussed whether or not the mare was sewed up (had a Caslick’s).  The exam found something quite different.


The external urethral orifice is in the vagina of the mare.  This is the opening in which urine is voided.  A piece of tissue called the transverse fold overlies this orifice.  Sometimes in maiden mares the transverse fold continues on both sides of the vagina forming the hymen.  Sometimes the hymen is complete and imperforate causing breeding to be ineffective.  The tissue must be removed before breeding can occur. 


The mare in this case did not have a complete imperforate hymen but an incomplete one.  There was a solid band of tissue running top to bottom that split the vagina in half.  This band of hymen would not permit the stallion to breed the mare.  After transecting this tissue, the vagina was open allowing breeding to occur. 


There are many reasons why a mare might come up open but a careful examination can often find the problem.  In some cases, like this one, the answer is quite straight forward and easily fixed.

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