Reproduction is key to species survival, and reproductive physiology represents a high priority investigative area for conservation biology, as it provides a basic understanding of critical life-history traits, information that is helpful for the establishment of management strategies. Here, we generated knowledge about the reproductive endocrinology of the hoary fox (Lycalopex vetulus), a small canid (2.5-4 kg) endemic to open areas of the Brazilian Cerrado and listed in the Brazilian National List of Endangered species. Specifically, we utilized non-invasive hormone monitoring methods to assess oestrogen and progestagen metabolites from eight female hoary foxes housed in five zoological institutions in the state of São Paulo-Brazil. We observed the elevations of oestrogen and progestagen metabolites between July and September in six of the eight females. No significant evidence of ovarian activity was observed during other months. Two females, who shared the same enclosure, did not show a pattern of reproductive cyclicity. Based on these characteristics, we concluded that captive hoary foxes are seasonal monoestric, with the beginning of the oestrus cycle occurring mainly in July followed by 2 months of the luteal phase when conception does not occur. We suggest the dosage of faecal metabolites of estradiol and progesterone could be used to differentiate the reproductive period from a non-reproductive period in Lycalopex vetulus females, providing relevant information about their reproductive biology that may contribute to species conservation and management strategies, such as increased ex situ reproductive success.

中文翻译：

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通过无创荷尔蒙监测技术首次评估白狐（Lycalopex vetulus）的季节性卵巢周期性。

繁殖是物种生存的关键，而繁殖生理学是保护生物学的一个重要优先领域，因为它提供了对关键生命史特征的基本理解，有助于建立管理策略。在这里，我们获得了关于白狐（Lycalopex vetulus）的生殖内分泌学的知识，白狐是巴西塞拉多开放地区的特有小犬科犬（2.5-4 kg），被列入巴西国家濒危物种名录。具体来说，我们利用非侵入性激素监测方法评估了来自巴西圣保罗州五个动物学机构的八只雌性白狐的雌激素和孕激素代谢产物。我们观察到七月至九月之间八位女性中六位女性的雌激素和孕激素代谢产物升高。在其他月份没有观察到卵巢活动的明显证据。共享同一围栏的两名雌性没有显示出生殖周期的模式。根据这些特征，我们得出结论，圈养的白狐属于季节性单雌性，发情周期的开始主要发生在7月，然后是黄体期的2个月（未受孕）。我们建议雌性粪便和孕酮的粪便代谢产物的剂量可用于区分雌性天牛的生殖期与非生殖期，并提供有关其生殖生物学的相关信息，这些信息可能有助于物种保护和管理策略，