Effect of surgical technique for unilateral orchiectomy on subsequent testicular function inMiniatureHorse stallions

Abstract

SummaryReasons for performing study: Management decisions on unilateral orchiectomy are often influenced by the potential for post operative return to successful breeding. The effects of 2 surgical methods (first intention [FI] vs. second intention [SI] incision healing) for unilateral orchiectomy on resulting semen quality and scrotal temperature were evaluated. Objective: To evaluate the effects of 2 surgical unilateral orchiectomy techniques on scrotal healing, size of the remaining testis and post operative sperm quality. Materials and methods: Unilateral orchiectomy was performed on mature Miniature Horse stallions. Semen was collected prior to and up to 60 days after, unilateral orchiectomy. Semen parameters, scrotal and body temperatures, testis volume and days to incision healing were evaluated. Results: There was no effect of treatment or time on percent total sperm motility. Total sperm numbers were higher (P<0.05) 60 days after unilateral orchiectomy compared with 14 and 30 days. Percent viable sperm were higher (P<0.05) 30 and 60 days compared with pre-and 14 day post unilateral orchiectomy. Scrotal temperatures were lower after unilateral orchiectomy compared with preoperative values (PՅ0.003). Higher scrotal temperatures were recorded in Group FI, as compared with Group SI, during recovery from anaesthesia and at 1 and 2 h after surgery (P = 0.02). Mean time to incision healing was less in Group FI (10.0 days) than in Group SI (21.5 days; P = 0.05). Conclusion: In this study, total sperm motility was maintained and size of the remaining testis, total sperm numbers and percent viable sperm increased after unilateral orchiectomy. Incision healing time was shorter in Group FI; however, surgical technique did not have an effect on semen quality at 30 and 60 days post unilateral orchiectomy. Potential relevance: These data suggest that surgical technique for unilateral orchiectomy may not dramatically influence function of the remaining testis.

Sperm DNA quality evaluated by comet assay and sperm chromatin structure assay in stallions after unilateral orchiectomy

“…It is unclear how soon after orchiectomy a stallion can return to breeding service due to the local inflammation and heat produced by the surgical procedure; therefore, it is often assumed that a minimum of one spermatogenic cycle (w60 days) should be allowed for sperm quality to return to pre-UO levels. In a previous complementary study, sperm quality (i.e., motility, morphology, viability) did not change at 14, 30, or 60 days after UO [16], compared to pre-UO levels. These results suggested that the degree of scrotal inflammation surrounding the surgical site after UO represented a "mild" testis stress that was not sufficient to elicit a decline in traditional sperm quality measures; however, DNA quality was not evaluated.…”

“…This present study compared the results of two DNA assays using the same ejaculates from a previous study [16] to determine whether a "mild" testis stress could be detected by either of the assays. It seems unlikely that DNA quality would be reduced in a model in which sperm motility, morphology, or viability were not affected; nevertheless, lower DNA quality was detected by both assays in the present study.…”

“…Semen was collected from nine mature Miniature Horse stallions after UO, using a Miniature Horse mare for sexual stimulation, a breeding phantom for mounting and a 33-cm length Missouri-model artificial vagina (Missouri-Style AV, C26716N; Nasco, Fort Atkinson, WI, USA), and processed as previously reported [16]. All animal procedures were carried out following the Institutional Animal Ethics Committee guidelines.…”

“…Therefore, it is of particular interest to study changes in sperm DNA in otherwise normal sperm (based on classical measures of sperm morphology and motility). A previous complementary study found no effect of unilateral orchiectomy (UO) on sperm motility, viability, morphology, and total sperm numbers at 14, 30, or 60 days after UO [16], but DNA quality was not evaluated.…”

Science in brief: Clinical highlights from the American Association of Equine Practitioners' 58th Annual Convention and Equine Veterinary Journal Supplement 43

“…McCormick et al . investigated the effect of unilateral orchiectomy via parainguinal approach in Miniature Horse stallions and found that compensatory hypertrophy was evident by 30 days post operatively . Incisions were either surgically closed or left to heal by second intention; mean (± s.d.)…”