Pre-ovulatory follicular temperature in bi-ovular cows

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Issue date
2019Suggested citation
López Gatius, Fernando;
Hunter, Ronald Henry Fraser;
.
(2019)
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Pre-ovulatory follicular temperature in bi-ovular cows.
Journal of Reproduction and Development, 2019, vol. 65, núm. 2, p. 191-194.
https://doi.org/10.1262/jrd.2018-111.
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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.