Retrograde ejaculation in a stallion

Azoospermia and Y Chromosome-Autosome Translocation in a Friesian Stallion

This case report describes spermatogenic arrest and azoospermia in a stallion with a unique Y chromosome-autosome translocation. Clinical diagnosis of azoospermia was based on history of infertility and evaluation of ejaculates collected for artificial insemination. Clinical and ultrasonographic evaluation of the external and internal genitalia did not reveal any abnormalities except for smaller than normal testicular size. Azoospermia of testicular origin was confirmed by determining alkaline phosphatase concentration in semen. Histological evaluation of testicular tissue after castration confirmed early spermatogenic arrest. Cytogenetic evaluation showed the presence of translocation between the Y chromosome and chromosome 13. To the authors' knowledge, this is the first case of azoospermia with a cytogenetically detected Y chromosome abnormality, suggesting that the horse Y chromosome may carry sequences critical for normal spermatogenesis.

Effect of non-sperm cells removal with single-layer colloidal centrifugation on myeloperoxidase concentration in post-thaw equine semen

Myeloperoxidase (MPO) is a pro-oxidant enzyme contained in and released by neutrophils during degranulation or after lysis. Post-thaw semen contains MPO and its concentration is associated with decreased sperm motility. Recently, MPO concentration in post-thaw semen was shown to be associated with the presence of non-sperm cells (NSC). The objective of this study was to evaluate the effect of a single-layer colloidal centrifugation before cryopreservation on NSC and MPO concentrations in equine semen. The experimental design consisted of freezing semen with or without previous centrifugation through two concentrations of single-layer colloid media. Non-sperm cells and MPO concentrations were assessed in pellet and upper layer at each step of the procedure and MPO was detected in cells by immunocytochemistry. Single-layer colloid centrifugation decreased NSC and MPO concentrations in post-thaw semen. The MPO concentration was correlated with concentration of NSC in the upper layer of the supernatant. In post-thaw semen, with or without previous single-layer colloid centrifugation, MPO concentration was correlated with concentration of NSC. Overall, neutrophils were rarely observed and NSC were mainly epithelial cells or cellular debris, as demonstrated by MPO immunocytochemistry. At all steps of the semen processing and cryopreservation, MPO immunostaining was clearly identified only on NSC. In conclusion, our study shows that NSC present in fresh semen release MPO during freezing.

Retrograde ejaculation associated spontaneous sperm cystolithiasis in four rhesus macaques (Macaca mulatta)

Retrograde ejaculation (RE) has been reported in humans and animals but RE with subsequent sperm calculi has rarely been reported. This report documents clinical and pathological findings of spontaneous sperm cystolithiasis in four rhesus macaques. While this condition has been associated with repeated electroejaculation, spontaneous sperm cystolithiasis is highly unusual. The animals presented with either stranguria, dysuria, hematuria, distended abdomen or lethargy. Ultrasound examination revealed several hyperechoic masses within the lumen of the urinary bladder. The animals were euthanized due to poor prognosis or study end points. Postmortem examination revealed multiple angular, amorphous, soft to firm, pale yellow to greenish-brown and variably sized calculi in the lumen of the urinary bladder or prostatic/penile urethra. Histologically, the calculi were composed of numerous sperm embedded in abundant brightly eosinophilic matrix. Based on gross and histologic findings, RE associated sperm cystolithiasis was diagnosed, with ulcerative urethritis as the major primary apparent etiology. To the authors' knowledge, this is the first report of four spontaneous cases of sperm cystolithiasis in rhesus macaques.

Azoospermia associated with bilateral segmental aplasia of the ductus deferens in a stallion

A 3-year-old Quarter Horse halter stallion was referred for routine semen evaluation. Physically, the stallion's reproductive organs appeared normal. Repeated semen evaluations did not reveal any spermatozoa. Because high activities of alkaline phosphatase are detected in the epididymal fluid and indicative of complete ejaculation, alkaline phosphatase activities were analyzed in several samples, which yielded activities far less than reference values and suggested a blockage of the reproductive tract. Endoscopic evaluation of the urethra and the bulbourethral, prostate, and urethral gland ducts did not reveal abnormalities. The left ductus deferens was exposed surgically, and attempts to pass a catheter through it in a normograde direction met resistance after 20 cm. Laparoscopic abdominal surgery revealed the ductus deferens tapered to a thin structure just cranial to the entrance in the urogenital fold, cranial and lateral to the bladder. Both ductus deferentia were similarly affected. The symmetry and bilateral nature of the abnormalities were strong indications of a possible congenital defect.