{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T01:41:24Z","timestamp":1760060484688,"version":"build-2065373602"},"reference-count":40,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2025,8,23]],"date-time":"2025-08-23T00:00:00Z","timestamp":1755907200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Veterinary Sciences"],"abstract":"<jats:p>Cryptorchidism is a common congenital disorder in male horses characterized by the failure of one or both testes to descend into the scrotum. This developmental anomaly has important clinical, surgical, and economic implications, particularly in breeding animals. This retrospective study investigates the prevalence and laterality of cryptorchidism in a large equine population presented to two veterinary referral hospitals\u2014Colorado State University Veterinary Teaching Hospital (CSU VTH, 1984\u20132014) and Oakridge Equine Hospital (OEH, 2008\u20132023). Medical records were reviewed to identify affected horses, and data on breed, age, and laterality of retained testes were collected. Anatomical location of retention (inguinal vs. abdominal) was excluded due to inconsistent documentation across the study period. A total of 777 horses met the inclusion criteria, with Quarter Horses comprising the majority of clinical cases. Quarter Horses exhibited a strong predisposition for left-sided testicular retention, whereas Thoroughbreds and Arabians more commonly presented with right-sided retention. These breed-specific trends in laterality suggest possible developmental factors influencing testicular descent. Understanding these patterns can aid in clinical diagnosis, improve surgical planning, and contribute to evidence-based breeding recommendations aimed at reducing the incidence of cryptorchidism in equine populations.<\/jats:p>","DOI":"10.3390\/vetsci12090796","type":"journal-article","created":{"date-parts":[[2025,8,25]],"date-time":"2025-08-25T00:10:36Z","timestamp":1756080636000},"page":"796","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Retrospective Evaluation of Cryptorchid Sidedness at Colorado State University Between 1984 and 2014 and Oakridge Equine Hospital Between 2008 and 2023"],"prefix":"10.3390","volume":"12","author":[{"given":"Hannah","family":"Fain","sequence":"first","affiliation":[{"name":"Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2246-9742","authenticated-orcid":false,"given":"Dean A.","family":"Hendrickson","sequence":"additional","affiliation":[{"name":"Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Matthew T.","family":"Buesing","sequence":"additional","affiliation":[{"name":"Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3522-5587","authenticated-orcid":false,"given":"Gregg","family":"Griffenhagen","sequence":"additional","affiliation":[{"name":"Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2025,8,23]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"467","DOI":"10.1111\/j.2042-3306.1986.tb03692.x","article-title":"Epidemiological features of 5009 cases of equine cryptorchism","volume":"18","author":"Hayes","year":"1986","journal-title":"Equine Vet. J."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"144","DOI":"10.1159\/000181051","article-title":"The Embryology of Testicular Descent","volume":"30","author":"Wensing","year":"1988","journal-title":"Horm. Res."},{"key":"ref_3","unstructured":"Auer, J.A., Stick, J.A., Kummerle, J.M., and Prange, T. (2019). Equine Surgery, Elsevier. [5th ed.]. Available online: https:\/\/bookshelf.health.elsevier.com\/reader\/books\/9780323636193\/epubcfi\/6\/158[%3Bvnd.vst.idref%3Did_chp00060_s1]!\/4\/2\/4\/2[CN]\/3:0[%2CCha]."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"489","DOI":"10.1016\/0093-691X(81)90082-0","article-title":"Clinical, morphological and endocrinological aspects of cryptorchidism in the horse","volume":"16","author":"Coryn","year":"1981","journal-title":"Theriogenology"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1095\/biolreprod1.Supplement_1.1","article-title":"Development of mammalian testes and genital ducts","volume":"1","author":"Gier","year":"1969","journal-title":"Biol. Reprod."},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Wensing, C.J.G., Colenbrander, B., and van Straaten, H.W.M. (1980). Normal and Abnormal Testicular Descent in Some Mammals. Descended and Cryptorchid Testis, Springer.","DOI":"10.1007\/978-94-009-8840-8_10"},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Hutson, J. (2019). The Testis. Clinical Embryology, Springer.","DOI":"10.1007\/978-3-319-26158-4_46"},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Han, H., Dong, H., Chen, Q., Gao, Y., Li, J., Li, W., Dang, R., and Lei, C. (2020). Transcriptomic Analysis of Testicular Gene Expression in Normal and Cryptorchid Horses. Animals, 10.","DOI":"10.3390\/ani10010102"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"442","DOI":"10.1016\/j.jevs.2013.09.001","article-title":"Anti-m\u00fcllerian hormone as a diagnostic marker for equine cryptorchidism in three cases with equivocal testosterone concentrations","volume":"34","author":"Claes","year":"2014","journal-title":"J. Equine Vet. Sci."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"541","DOI":"10.1530\/REP-06-0272","article-title":"Cryptorchidism in common eutherian mammals","volume":"133","author":"Amann","year":"2007","journal-title":"Reproduction"},{"key":"ref_11","first-page":"S421","article-title":"Equine cryptorchidism","volume":"5","author":"Shira","year":"1983","journal-title":"Compend. Contin. Educ. Pract. Vet."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"538","DOI":"10.1111\/evj.12013","article-title":"Expression of anti-M\u00fcllerian hormone, CDKN1B, connexin 43, androgen receptor and steroidogenic enzymes in the equine cryptorchid testis","volume":"45","author":"Almeida","year":"2013","journal-title":"Equine Vet. J."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"209","DOI":"10.1292\/jvms.18-0057","article-title":"A case of equine cryptorchidism with undetectable serum anti-m\u00fcllerian hormone","volume":"82","author":"Murase","year":"2020","journal-title":"J. Vet. Med. Sci."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"31","DOI":"10.58292\/ct.v15.9648","article-title":"Cryptorchidism in stallions","volume":"15","author":"Arroyo","year":"2023","journal-title":"Clin. Theriogenology"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"179","DOI":"10.1111\/j.2042-3306.1975.tb03263.x","article-title":"Experiences with a Diagnostic Test for Equine Cryptorchidism","volume":"7","author":"Cox","year":"1975","journal-title":"Equine Vet. J."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"S45","DOI":"10.1016\/j.jevs.2016.06.076","article-title":"Application of Various Techniques in Localizing Retained Testes in Horses Before Cryptorchidectomy","volume":"43","author":"Pozor","year":"2016","journal-title":"J. Equine Vet. Sci."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"150","DOI":"10.1111\/eve.12419","article-title":"Inguinal percutaneous ultrasound to locate cryptorchid testes","volume":"28","author":"Coomer","year":"2016","journal-title":"Equine Vet. Educ."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"777","DOI":"10.1016\/j.cveq.2006.08.006","article-title":"Laparoscopic Cryptorchidectomy and Ovariectomy in Horses","volume":"22","author":"Hendrickson","year":"2006","journal-title":"Vet. Clin. N. Am.-Equine Pract."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"335","DOI":"10.1111\/j.1532-950X.1997.tb01507.x","article-title":"Laparoscopic cryptorchid castration in standing horses","volume":"26","author":"Hendrickson","year":"1997","journal-title":"Vet. Surg."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"138","DOI":"10.1111\/j.1532-950X.1998.tb00110.x","article-title":"Ventral abdominal approach for laparoscopic cryptorchidectomy in horses","volume":"27","author":"Ragle","year":"1998","journal-title":"Vet. Surg."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"372","DOI":"10.1016\/S0025-6196(12)60660-0","article-title":"Malignant Potential of the Cryptorchid Testis","volume":"66","author":"Benson","year":"1991","journal-title":"Mayo Clin. Proc."},{"key":"ref_22","unstructured":"Kolon, T.F. (2008). Cryptorchidism. The Kelalis-King-Belman Textbook of Clinical Pediatric Urology Study Guide, Taylor & Francis Ltd."},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Favorito, L.A. (2020). Testicular migration. Translational Research in Pediatric Urology: Basic and Clinical Aspects, Springer.","DOI":"10.1007\/978-3-030-50220-1"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"203","DOI":"10.1111\/j.1751-0813.2005.tb11648.x","article-title":"Equine hemi-castration: Review of the condition, prevalence, aetiology, diagnosis and surgical management","volume":"83","author":"Maxwell","year":"2005","journal-title":"Aust. Vet. J."},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Waqas, M.S., Arroyo, E., and Tibary, A. (2024). Diagnostic Approach to Equine Testicular Disorders. Vet. Sci., 11.","DOI":"10.3390\/vetsci11060243"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"113","DOI":"10.1111\/j.2042-3306.1979.tb01321.x","article-title":"An Analysis of 500 cases of Equine Cryptorchidism","volume":"11","author":"Cox","year":"1979","journal-title":"Equine Vet. J."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"777","DOI":"10.2460\/javma.246.7.777","article-title":"Cryptorchidectomy in equids: 604 cases (1977\u20132010)","volume":"246","author":"Hartman","year":"2015","journal-title":"J. Am. Vet. Med. Assoc."},{"key":"ref_28","unstructured":"(2025, May 28). R: The R Project for Statistical Computing. Available online: https:\/\/www.r-project.org\/."},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Ripley, B.D., and Venables, W.N. (2002). Modern Applied Statistics with S, Springer. [4th ed.].","DOI":"10.1007\/978-0-387-21706-2"},{"key":"ref_30","unstructured":"(2024, March 19). Package \u201cemmeans\u201d Type Package Title Estimated Marginal Means, aka Least-Squares Means. Available online: https:\/\/github.com\/gregg-g\/Fain_Hend_crypt_23.git."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"136","DOI":"10.1016\/j.livsci.2016.06.012","article-title":"Genetic parameters of cryptorchidism and testis size in Friesian colts","volume":"190","author":"Schurink","year":"2016","journal-title":"Livest. Sci."},{"key":"ref_32","first-page":"242","article-title":"Use of transabdominal ultrasonography to determine the location of cryptorchid testes in the horse","volume":"Volume 38","author":"Schambourg","year":"2006","journal-title":"Handbook of Environmental Chemistry, Volume 5: Water Pollution"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"151","DOI":"10.1071\/RD9940151","article-title":"Hormonal control of testicular descent and the cause of cryptorchidism","volume":"6","author":"Hutson","year":"1994","journal-title":"Reprod. Fertil. Dev."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"85","DOI":"10.1111\/j.2042-3306.1973.tb03200.x","article-title":"Testosterone in Normal, Cryptorchid and Castrated Male Horses","volume":"5","author":"Cox","year":"1973","journal-title":"Equine Vet. J."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"15","DOI":"10.1294\/jes.26.15","article-title":"Anti-M\u00fcllerian hormone as an indicator of hemi-castrated unilateral cryptorchid horses","volume":"26","author":"Murase","year":"2015","journal-title":"J. Equine Sci."},{"key":"ref_36","first-page":"346","article-title":"Noninvasive Inguinal Approach for Cryptorchidectomy in Thirty-eight Stallions","volume":"29","author":"Arighi","year":"1988","journal-title":"Can. Vet. J."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"931","DOI":"10.2460\/javma.231.6.931","article-title":"Comparison of the diagnosis and management of unilaterally castrated and cryptorchid horses at a referral hospital: 60 cases (2002\u20132006)","volume":"231","author":"Marshall","year":"2007","journal-title":"J. Am. Vet. Med. Assoc."},{"key":"ref_38","first-page":"1280","article-title":"Cryptorchidism in horses. Part 1. Anatomy, causes, and diagnosis","volume":"Volume 19","author":"Rodgerson","year":"1997","journal-title":"The Auburn Compendium"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"651","DOI":"10.1016\/0090-4295(77)90312-0","article-title":"Anatomy and function of scrotal ligament","volume":"9","author":"Shafik","year":"1977","journal-title":"Urology"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"605","DOI":"10.1136\/adc.39.208.605","article-title":"The descent of the testis","volume":"39","author":"Scorer","year":"1964","journal-title":"Arch. Dis. Child."}],"container-title":["Veterinary Sciences"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2306-7381\/12\/9\/796\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,9]],"date-time":"2025-10-09T18:34:51Z","timestamp":1760034891000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2306-7381\/12\/9\/796"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,8,23]]},"references-count":40,"journal-issue":{"issue":"9","published-online":{"date-parts":[[2025,9]]}},"alternative-id":["vetsci12090796"],"URL":"https:\/\/doi.org\/10.3390\/vetsci12090796","relation":{},"ISSN":["2306-7381"],"issn-type":[{"type":"electronic","value":"2306-7381"}],"subject":[],"published":{"date-parts":[[2025,8,23]]}}}