Reproductive management of silver foxes (Vulpes vulpes) in captivity

Specific protocols need to be developed that take into consideration the re quirements of silver foxes. This study was designed to investigate the repr oduction of 26 pairs of silver foxes (Vulpes vulpes). Reproduction paramete rs (breeding season, age at puberty, fecundity and fertility) of the foxes were examined under experimental conditions, and new techniques to optimize fox breeding were assessed. Staining of the vaginal smears with the double Harris-Schorr stain allowed for the precise detection of estrus and proved to be more reliable than simply measuring vaginal resistance. Ultrasonogra phy was demonstrated to be useful for pregnancy diagnosis and prediction of parturition. Results demonstrate that the methods reported in this paper a re easily applicable to similar studies carried out on small groups of anim als within the framework of fox animal experimentation. (C) 2000 by Elsevie r Science Inc.