Abstract

Within zoological institutions, there is a growing realization that assisted reproductive technologies (ART) will be necessary for genetic management and long-term sustainability of imperiled felids.¹ Semen banking and artificial insemination (AI) are the most readily applicable ART for management of felid populations, but differences in physiology necessitate fundamental research in each felid species before the potential of ART can be realized. The jaguar (Panthera onca) is the largest wild cat native to the Americas and a focal species for conservation efforts, but their reproductive biology is poorly understood and a successful jaguar AI has never been reported. Accordingly, our objectives in this study were to (1) assess ovarian sensitivity to oral progestin, (2) evaluate ovarian responses following gonadotropin treatment, and (3) investigate fertility with fixed time laparoscopic oviductal AI. Adult female jaguars were fed oral progestin (Altrenogest, Regu-Mate®, Merck Animal Health, Summit, NJ, USA; 0.044 mg/kg n=2; 0.088 mg/kg n=2) daily for 45 days. Longitudinal fecal hormone analyses revealed that neither altrenogest dose was sufficient to suppress ovarian activity. Therefore, the progestin dosage was increased for Objectives 2 and 3. Females were fed altrenogest (0.088 mg/kg, n=4; 0.176 mg/kg, n=4) for 45–48 days, and following a 5-day withdrawal period, treated with exogenous gonadotropins: 600 IU equine chorionic gonadotropin (eCG) followed 82 h later by 5000 IU porcine luteinizing hormone (pLH). At 43–48 h post-pLH, females were evaluated laparoscopically for ovarian response, and inseminated in each oviduct with fresh semen (1.5–4.2x10⁶ motile sperm/oviduct). If the oviduct could not be cannulated (n=5 oviducts total), fresh semen was deposited into the ipsilateral uterine horn (5–12.6x10⁶ motile sperm/horn). All females produced multiple follicles in response to gonadotropin treatment (21.3±4.2 follicles plus corpora lutea (CL); mean±SE), but ovulatory rate was low (18.7±9.3% of follicles) and females averaged only 3.6±2.0 CL. No births resulted from the AIs. For subsequent AI procedures, three adjustments were made to the hormone treatment protocol: (1) the progestin withdrawal period was increased to 7 days, (2) eCG-pLH interval was increased to 90–92 h, and (3) pLH dose was increased to 10,000 IU. Females (n=5) all received the high progestin dose (0.176 mg/kg). At laparoscopy, all females had multiple ovulations with 57.1±6.9% of follicles ovulating, forming 14.2±2.3 CL per female. Females were inseminated laparoscopically in each oviduct with fresh semen (2.5–4.4x10⁶ motile sperm/oviduct) except in two cases the oviduct could not be cannulated and 5–7.5x10⁶ motile sperm was deposited into the ipsilateral uterine horn. One of the five females conceived and, after a 104-day gestation period, gave birth to a single viable cub, the first jaguar ever produced from AI. In summary, oral progestin and eCG/pLH gonadotropin treatment, following species-specific adjustments, proved to be effective for ovarian synchronization in the jaguar, providing a consistent and robust ovarian response. The birth of a live cub following AI further confirms the effectiveness of the hormone regimen and provides an important milestone towards the application of ART for population management of this imperiled felid.

Acknowledgments

This work would not have been possible without the generous assistance of the veterinary and animal care staff at Associação Mata Ciliar.

Literature Cited

1.  Swanson WF. Application of assisted reproduction for population management in felids: the potential and reality for conservation of small cats. Theriogenology. 2006;66(1):49–58.