Pre-ovulatory follicular temperature in bi-ovular cows
In a previous study on monovular cows, follicles revealed a mean antral (follicular fluid) temperature 1.54°C cooler than rectal temperatures in ovulating cows, whereas no such temperature differences were detected in non-ovulating cows. The present study adds to our previous work, this time considering 24 bi-ovular cows (one follicle per ovary). In order to increase the number of pre-ovulatory follicles failing to ovulate, this study was performed under heat-stress conditions. Follicular temperatures of the ovulating follicles (n = 31) were 0.93°C significantly cooler (P < 0.0001) than rectal temperatures, whereas no significant differences in temperature were found in non-ovulating follicles (n = 17). Eight cows became pregnant. The results of the present study indicate that, similar to those in monovular cows, pre-ovulatory follicles in bi-ovular cows were cooler than deep rectal temperatures and those temperature gradients were not found in follicles showing ovulation failure.
Journal or Serie
Journal of Reproduction and Development, 2019, vol. 65, núm. 2, p. 191-194