• horse;
  • unilateral orchiectomy;
  • castration;
  • sperm;
  • viability


Reasons 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.


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.


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 (P≤0.003). 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).


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.