Integrated Reproductive and Cytogenetic Assessment of Infertility in a Captive Jaguar ( Panthera onca )

ABSTRACT Background Ex situ conservation of threatened felid species requires a thorough understanding of reproductive biology and realistic evaluation of assisted reproductive techniques (ART). In jaguars ( Panthera onca ), however, knowledge of reproductive limitations in captivity remains scarce. Objectives On the basis of a comprehensive single‐timepoint assessment, this study applied an integrated clinical, endocrinological, semen analysis and cytogenetic approach to investigate persistent infertility in a captive jaguar breeding pair recommended for reproduction within the European Association of Zoos and Aquaria (EAZA) programme. Methods Both animals underwent comprehensive reproductive and health assessments, including genital examination, ultrasonography, haematological and hormonal profiling. Semen quality was evaluated following electroejaculation, and cytogenetic screening was performed to detect potential chromosomal abnormalities using conventional staining, banding techniques and fluorescence in situ hybridization. Results Cytogenetic analyses revealed a standard felid karyotype (2 n = 38) in both individuals, with no evidence of aneuploidy or structural chromosomal rearrangements. Clinical and endocrinological assessments of the female did not identify abnormalities likely to impair fertility. In contrast, semen evaluation of the male revealed markedly reduced ejaculate volume, low sperm concentration, low sperm motility and a high proportion of morphologically abnormal spermatozoa, consistent with severe teratozoospermia. Conclusions Taken together, these findings indicate that although genetic and general clinical contraindications for reproduction were absent, semen quality represents a critical limiting factor for successful natural breeding. Under the observed reproductive profile, ART feasibility requires functional validation through sperm selection and competence assays. This study highlights the value of combining cytogenetic and reproductive assessments to support evidence‐based decision‐making in captive breeding programmes and provides novel cytogenetic data for the jaguar.