Abstract

The time of ovulation following removal of pouch young (RPY) was determined in 240 possums by repeated laparoscopic observation of the ovaries, and in a subset of these animals (n=20) also from changes in vaginal mucus. In a separate experiment (n=18), the time of oestrus was estimated from an influx of epithelial cells and leucocytes in urine, and confirmed by mating and hormonal data. A preovulatory follicle was observed at laparoscopy in all animals that ovulated (n=138), but not in any that did not (n=102). An influx of neutrophils in vaginal mucus occurred in 12/20 possums, including 4 that failed to ovulate. An increase in epithelial cells in urine was observed in 9/12 possums that exhibited an LH surge. However, this change occurred after the time of the preovulatory LH surge in 6 of those animals and peak cell numbers varied widely between all animals. These studies confirm that although changes in the cell content of mucus and urine can retrospectively define stage of the oestrous cycle, they are of little value for predicting impending oestrus, the LH surge or ovulation

BJ, McLeod, EG Thompson, JL Crawford, PM Mahoney, and D Eckery

Proceedings of the New Zealand Society of Animal Production, Volume 59, , 236-238, 1999