Necrosis of the Spermatic Cord, Epididymis, and Testis of a Friesian Stallion Caused by Salmonella abortus equi

Importance
Trauma, inguinal herniation, and torsion of the spermatic cord are causes of inflammation of the spermatic cord, epididymis and testis of stallions. Epididymo-orchitis characterized by coagulative and liquefactive caused by Salmonella spp. has been reported to occur in humans, rams, and chickens, but we can find no similar reports in the stallion. This case report describes a stallion affected with epididymoorchitis caused by Salmonella abortus equi.

Diagnostic approach and treatment
A 5-year-old Friesian stallion was presented to the University of Tennessee's Veterinary Medical Center because of discomfort and enlargement of the right testis first observed four days previously. Examination revealed a thick plaque of edema and an enlarged right testis and spermatic cord. Palpation of the testis did not elicit signs of pain from the horse. Ultrasonographic examination, using Doppler, revealed hyperechoic areas in the right cord and testis consistent with necrosis. The right testis was moderately enlarged (7.1 cm diameter), and fluid was observed between the visceral and parietal tunics. The distal 3 cm of the spermatic cord had no blood flow. Testicular necrosis caused by torsion of the spermatic cord was suspected, and unilateral orchidectomy was recommended.

Results and discussion
During intra-operative examination, the right spermatic cord was observed to be oriented properly, but its distal 3 cm was necrotic. The cord and testis were edematous and contained areas of fibrosis. Scrotal fascia was thickened, and the parietal tunic was 6 to 7 mm thick and adhered to the testis. The testis and necrotic portion of the spermatic cord were excised using a closed technique of orchidectomy. The scrotal incision was sutured. Culture of foul-smelling exudate contained within the testis produced >500 colonies of Salmonella abortus equi. Severe, chronic, diffuse, necrosuppurative orchitis and epididymitis, and bacterial rods were observed during histological examination of the testis. The scrotal incision healed by first intention. The stallion returned to breeding after two months of sexual rest. Bacterial culture of semen collected from the stallion on three occasions during the next three months produced Salmonella abortus equi. Mares artificially inseminated with this semen became pregnant.