Retrograde ejaculation in a stallion.

Retrograde ejaculation was diagnosed in a 10-year-old Arabian stallion. Despite behavioral signs consistent with ejaculation, the collection receptacle of an artificial vagina remained devoid of semen on numerous occasions. Catheterization of the urinary bladder yielded large numbers of spermatozoa, even when an ejaculate was obtained, whereas low numbers (< 1 X 10(6)/ml) of spermatozoa are found in the bladder of clinically normal stallions after ejaculation. Endoscopic examination of the urethra, seminal colliculus, and bladder failed to reveal abnormalities. Medical treatment with imipramine hydrochloride apparently resulted in improvement initially, but was not curative. Further diagnostic and treatment measures were declined and the stallion was castrated. For stallions that seemingly fail to ejaculate or for ejaculates that contain lower seminal volumes or numbers of spermatozoa than expected, obtaining a urine sample after ejaculation via bladder catheterization is a simple diagnostic procedure that may be used to investigate the possibility of retrograde ejaculation.