Characterizing estrus by trans-abdominal ultrasounds, fecal estrone-3-glucuronide, and vaginal cytology in the Steller sea lion (Eumetopias jubatus)

摘要: Abstract The ability to monitor the estrus cycle in wild and captive marine species is important for identifying reproductive failures, ensuring a successful breeding program, monitoring animal welfare. Minimally invasive sampling methods populations have been developed, but results suggest these tools can be species-specific their precision accuracy. Therefore, minimally of trans-abdominal ultrasounds, fecal steroid analysis (estrone-3-glucuronide, E1G), vaginal cytology, were evaluated efficacy characterize population Steller sea lions (Eumetopias jubatus). Three adult females sampled over five seasons, resulting six profiles characterized by E1G, four cytology. Animals trained allow samples, swabs collected approximately daily. Of 76 ultrasound sessions attempted, 8 successfully visualized both ovaries. From scans, chronology ovarian changes during proestrus was estimated. time from detection developing follicles identification dominate follicle occurred 2–5 days corpus hemorrhagicum formed 4 later. However, because visualization ovaries prevented gastrointestinal system 88% this tool overall unreliable associated with estrus. To detect fine scale physiological estrus, we analyzed E1G (n = 62) cytology (n = 157) 15 before after each female's single copulation event (Day = 0). Changes had highest accuracy at detecting Day = 0. Fecal increased leading up peaked Day = 0, then declined. Although did observe characteristic increase superficial cells impending type cell which closest Day = 0 intermediate. uncertainty around peak intermediate cells, indicating greater than E1G. Collectively, that are viable lions, require daily gradual changes, limiting applicability studies populations.