Determination of oestrus and mating in captive female brushtail possums, Trichosurus vulpecula (Marsupialia : Phalangeridae), from urine samples

Abstract

Reproductive data were collected from captive brushtail possums, Trichosurus vulpecula, by examining daily urine samples for the presence of non-keratinised and keratinised epithelial cells, polymorphonuclear leucocytes, and sperm. Around the time of oestrus there was a massive increase in the number of epithelial cells and leucocytes in urine. The pattern of cell shedding was similar in mated and non-mated females undergoing either spontaneous ovulations or those induced by removal of pouch young. There was no difference between fertile or non-fertile oestrous cycles. During the 2-month sampling period, 97% of females showed changes in cell numbers indicative of oestrus and 72% of females were confirmed to have been mated by the presence of sperm. Conception rate was 74% and offspring were born 16–19 days after mating. When pouch young were removed, 85% of females were mated 7–15 days later and 77% of mated females produced pouch young. Compared with vaginal smears, collection and examination of urine was easier and faster, only one animal handler was required, the method was less stressful for the possum, and cell types in the sample were scored directly without the need for fixation and staining.