Azoospermia associated with bilateral segmental aplasia of the ductus deferens in a stallion.
Abstract: 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.
Publication Date: 2003-07-02 PubMed ID: 12830868DOI: 10.2460/javma.2003.222.1740Google Scholar: Lookup
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Summary
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This study documents a case of a 3-year-old Quarter Horse stallion with azoospermia, a condition where a male produces no sperm, which was found to be associated with a congenital defect, leading to bilateral segmental aplasia of the ductus deferens, the tubes responsible for sperm transport in male animals.
Case Summary
- The case involved a 3-year-old Quarter Horse halter stallion which was initially physically normal in terms of reproductive organs but showed zero spermatozoa in repeated semen evaluations.
- The stallion’s samples were tested for alkaline phosphatase, an enzyme usually found in epididymal fluid, indicative of complete ejaculation. The lower than usual activities of this enzyme suggested a possible blockage in the reproductive tract.
- No abnormalities were discovered during the endoscopic evaluation of the urethra and various ducts associated with the reproductive system. However, surgical exposure and attempted catheter insertion into the left ductus deferens faced resistance after 20 cm.
Laparoscopic Findings
- Laparoscopic abdominal surgery was carried out to investigate the issue further. It was found that the stallion’s ductus deferens tapered to a thin structure just before entering the urogenital fold, a part close to the bladder.
- This narrowing, or aplasia, of the ductus deferens was observed to be symmetrical and occurred in both ductus deferens, which led to the conclusion that the abnormality could be a congenital defect.
Concluding Remarks
- Azoospermia in the discussed Quarter Horse stallion case was revealed to be associated with bilateral segmental aplasia of the ductus deferens, a congenital defect absent sperm production and transport in the male reproductive system.
- The findings shed light on the potential congenital causes of azoospermia in equine species, highlighting the importance for broad and thorough testing when dealing with cases of infertility or sub-fertility in stallions.
Cite This Article
APA
Estrada A, Samper JC, Lillich JD, Rathi RR, Brault LS, Albrecht BB, Imel MM, Senne EM.
(2003).
Azoospermia associated with bilateral segmental aplasia of the ductus deferens in a stallion.
J Am Vet Med Assoc, 222(12), 1740-1707.
https://doi.org/10.2460/javma.2003.222.1740 Publication
Researcher Affiliations
- Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA.
MeSH Terms
- Alkaline Phosphatase / metabolism
- Animals
- Ejaculation
- Horse Diseases / etiology
- Horse Diseases / surgery
- Horses
- Male
- Oligospermia / etiology
- Oligospermia / surgery
- Oligospermia / veterinary
- Semen / cytology
- Spermatozoa
- Vas Deferens / abnormalities
- Vas Deferens / surgery
Citations
This article has been cited 2 times.- Bucci R, Parrillo S, Probo M, Varasano V, Romano A, Carluccio A. Case Report: Reproductive evaluation of a Murgese stallion with obstructive azoospermia, accumulation of hyaline material in the ampullae ducts, and corpora amylacea in vesicular glands. Front Vet Sci 2025;12:1571637.
- Waqas MS, Arroyo E, Tibary A. Diagnostic Approach to Equine Testicular Disorders. Vet Sci 2024 May 29;11(6).
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