Aspects of reproductive endocrinology in the red wolf (Canis rufus)

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Authors

Walker, Susan Lorene

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University of Guelph

Abstract

Reproductive endocrinology of the red wolf ('Canis rufus') was studied in captive animals by fecal enzyme immunoassay. In cycling females, estrogen metabolites increased through proestrus, reached maximal values during estrus and declined concurrent with rising progestin metabolite values. Progestin metabolite levels remained elevated until mid- to late luteal phase and then gradually declined to nadir levels. There was no significant difference between pregnant and ovulatory non-pregnant hormone profiles. Acyclic animals maintained basal ovarian hormone concentrations throughout the breeding season. During the periovulatory period, serum and fecal hormone profiles exhibited comparable trends. In male red wolves, changes in testosterone metabolite concentrations were consistent with photoperiod synchronization. Testosterone metabolite levels began to increase prior to the breeding season (November-December), and reached peak levels coincident with estrus in late winter (late February). It was concluded that sex determination through fecal steroid ratios of progestin/testosterone and testosterone/estrogen is possible only from late December to early May.

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Keywords

reproductive endocrinology, red wolf, Canis rufus, captive animals, fecal enzyme immunoassay

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