Dear all We are happy to announce our recent publication:
Serum estradiol and progesterone profiles during estrus, pseudopregnancy, and active gestation in Steller sea lions. Sattler R, Polasek L. Zoo Biology. 2017; 36:323–331. https://doi.org/10.1002/zoo.21381 Abstract: While the proximate driver behind the decline of the Westernstock of Steller sea lions (Eumetopias jubatus, >80% since 1970s) is likelymultifactorial, the population reduction may have been powered by a decrease infecundity. A harvest of Steller sea lions in the 1970s and 80s revealed a 30%reduction in the proportion of pregnant females from early (October–November)to late gestation (April–May). Identification and quantification of thesereproductive failures are difficult when we lack species-specific data onendocrinology associated with discrete stages of the reproductive cycle (i.e.,estrus, implantation, and gestation). We tracked changes in serum estradiol andprogesterone in three adult female Steller sea lions from 2011 to 2015. In allyears and most females, a discrete increase in estradiol was observed duringthe breeding season (June–August), indicative of estrus. Estradiolconcentrations from October to May in a pregnant female compared to hercorresponding values when non-pregnant did not consistently differ throughgestation. An elevation in progesterone was observed in all females and allyears beginning approximately in June and lasting through November. This likelyresults from progesterone production by the corpus luteum in both pregnant and pseudopregnantfemales. Serum progesterone shows promise as a diagnostic tool to identifypregnancy during months 3–5 (December–February) of the 8-month active gestationfollowing embryonic implantation. This study provides ranges of key hormonesduring estrus, embryonic diapause/pseudopregnancy, and gestation in pregnantand non-pregnant females for studying reproduction in Steller sea lions. A pdf can be obtained at http://onlinelibrary.wiley.com/doi/10.1002/zoo.21381/ Or email [email protected] to request a pdf. Best wishes, Renae
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