Doctoral Dissertations

Date of Award

12-2022

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Comparative and Experimental Medicine

Major Professor

Debra L. Miller

Committee Members

Brian K. Whitlock, Maria Spriggs, Michael E. Tewes, Clayton D. Hilton, William F. Swanson

Abstract

Recent studies of wild felid populations in southern Texas have shown loss of genetic variability and inbreeding depression over time, increasing the risk of reduced reproductive and immune fitness leading to an overall decrease in reproductive success, increase in disease susceptibility, and further population demise. Assessment of general health, pathogen exposure, and reproductive health can provide documentation of the possible effects of inbreeding and inform the development of conservation strategies. Assisted reproductive technologies have been used in many other species and can address behavioral or physical incompatibilities among breeding pairs, connect distant populations by transporting frozen gametes, preserve genetic diversity within liquid nitrogen tanks and link wild and human-managed populations without the movement of individuals. The main goals of this study were to: (1) determine the general and reproductive health status and pathogen prevalence of free-ranging ocelot and bobcat populations in south Texas, given the concern for the impact of declining genetic diversity on population health, (2) compare the effectiveness of urethral catheterization (UC) and ultra-rapid freezing (URF) to traditional cryopreservation methods as a field-friendly semen collection and cryopreservation combination, and (3) assess the use of laparoscopic oviductal artificial insemination (LO-AI) in human-managed ocelot females with semen from wild Texas males to explore the feasibility of this approach to facilitate ocelot pregnancies. While our populations did not show declines in general health, reproductive health parameters of wild ocelots were inferior to human-managed ocelot populations and bobcats exhibited low overall semen quality similar to other Lynx species. We found that UC collected samples were consistently damaged by urine contamination for ocelots and that electroejaculation with straw freezing was superior. For bobcats, while UC and URF appeared adequate, electroejaculation would need to be further explored. No pregnancies (0/5) have been produced in ocelots by LO-AI using frozen-thawed semen thus far; however, eventual success with this technique will allow the use of minimal sperm numbers to promote gene flow among isolated populations and re-establish extirpated populations with genetically diverse individuals. Further assessment of bobcat sperm viability in vivo will be required to demonstrate the practicality of these methods for future conservation initiatives.

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