CONICET | Buscador de Institutos y Recursos Humanos

One of the major concerns for the Jaguar conservation is the increase of habitat loss, fragmentation and hunting. The species has been virtually eliminated from much of its historical range. With the severe decline of the wild populations, it became increasingly important understanding the species basic reproductive physiology for a successful conservation program.We determined fecal estrogen and progesterone metabolite levels of a female jaguar maintained in captive conditions at the ?Jaguar Experimental Breeding Center? from The Conservation Land Trust, in the wetlands of Ibera Natural Reserve, Corrientes, Argentina. A male was allowed to mate when the female showed external signs of estrus. Fecal samples were collected daily from April-December of 2016 (n=208). Fecal extracts (0.5g wet feces in 80% methanol, 24 h extraction at 4°C) were analyzed by EIA using the Estradiol 17β-R0008 and Progesterone-R4859 antibodies (Coralie Munro, UC Davis, USA).Mean duration of the ovarian cycle (defined as the number of days between two consecutive estrogen peaks) of was 32.7±2.0 days (range: 28?37 days; n=4 estrous cycles). Mean estrous length was 6.2±0.4 days and luteal phase was 19.5±4.1 days, defined by a lapse of sustained high levels of progesterone (range: 11?27 days; n=4). Baseline concentrations of estradiol and progesterone were 9.5±0.5 and 137.1 ± 9.8 ng/g wet feces respectively. Peak fecal estradiol and progesterone concentrations reached values of 218.4± 59.1 and 1330.1±113.0 ng/g wet feces, respectively.The hormonal and behavioral data suggested that this female is polyestrous and that ovulation was not linked to the events of copulation alone, suggesting that spontaneous ovulation occurs regularly. This protocol was effective for monitoring the ovarian cycle in the jaguar, and the ovarian cycle duration and estrous length were coincident with the scarce data on this species.