Reproductive cycle of the steppe polecat (Mustela eversmanni)

• Published in: Journal of reproduction & fertility Vol. 88; no. 1; pp. 353 - 360
• Main Authors: Mead, R A, Neirinckx, S, Czekala, N M
• Format: Journal Article
• Language: English
• Published: England Society for Reproduction and Fertility 01.01.1990
• Subjects: Animals; Carnivora - physiology; Estrogens, Conjugated (USP) - urine; Estrus - physiology; Female; Ferrets - physiology; Litter Size; Male; Pregnancy; Progesterone - urine; Reproduction - physiology; Seasons; Testis - anatomy & histology; Testis - physiology
• DOI: 10.1530/jrf.0.0880353
• ISSN: 1470-1626; 0022-4251

In laboratory conditions, in a natural photoperiod, testicular redevelopment began in late December. Maximal testis size was attained by the end of February. Testicular regression began in mid-May and was complete by the end of August. Oestrus was first observed in late March and continued throughout April. Females mated for the first time between 30 March and 8 April. Mating generally coincided with peak concentrations of urinary oestrone conjugates and when vaginal lavages contained >90% cornified epithelial cells. Blastocyst implantation occurred by Day 13 and the post-implantation period was 29 days. Gestation ranged from 39 to 43 days and first parturition occurred in mid-May. Concentrations of urinary oestrone conjugates and free progesterone were elevated during the first half of pregnancy, reaching maximum values at mid-pregnancy, and then gradually declined as parturition neared. Litter size of primiparous females averaged 6·8 young/female. Females that were pseudopregnant or lost their litters shortly after birth, and several with weaned kits, exhibited a second oestrus. Keywords: steppe polecat; oestrous cycle; testis; pregnancy; urinary steroids