Semen collection and characterization of normative reproductive traits in free-ranging ocelots (Leopardus pardalis) and bobcats (Lynx rufus) in southern Texas

Decreased genetic diversity and possible inbreeding depression have recently been documented in the last wild ocelot (Leopardus pardalis) population in the United States. One consequence of inbreeding depression in felids may be reduced semen quality which can adversely affect reproductive potential. Detailed assessments of reproductive parameters in wild individuals and populations can be conducted using assisted reproductive technologies, such as semen collection and analysis. For most felid species, semen has traditionally been collected via electroejaculation (EEJ²); however, an alternative method has been developed using alpha-2 agonist drugs to induce direct sperm release into the urethra, allowing collection by catheterization without requiring specialized equipment. The goal of this study was to characterize normative reproductive traits in free-ranging ocelots and co-occurring bobcats (Lynx rufus) in southern Texas and assess the effectiveness of urethral catheterization (UC³) for semen recovery in both species. For semen collection, free-ranging cats were live-captured and anesthetized using intramuscular ketamine and medetomidine/dexmedetomidine (alpha-2 agonist) with UC conducted 20–40 minutes post-induction. In ocelots only, EEJ was subsequently performed if UC failed to recover a viable sample. Semen collection was attempted in 31 felids (n=9 ocelots; n=22 bobcats), with sperm recovery by UC in seven of nine ocelots (78 %) and 14 of 22 bobcats (66 %), and by EEJ in four of five ocelots (80 %). For ocelots, the percentage of primary morphologic abnormalities was higher (p<0.001) for UC (47.75 ± 6.7; mean ± SEM) compared to EEJ (9 ± 2.7) but percent normal morphology (MORPH) did not differ between UC and EEJ (p=0.218). In wild ocelots, seminal parameters appeared lower relative to historical values reported for zoo-managed ocelots, possibly related to reduced heterozygosity. In wild bobcats, seminal traits were inferior to those of ocelots but similar to reports for other zoo-managed Lynx species. In conclusion, detailed male reproductive traits have been characterized for the first time in wild, free-ranging ocelots and bobcats in southern Texas. Although UC allowed semen recovery for assessment of seminal traits in both species, EEJ produced higher quality samples in ocelots when applied after UC while also mitigating the adverse impact of urine contamination observed frequently with both collection methods.