Periovulatory administration of therapeutic and supratherapeutic doses of firocoxib does not impair induced ovulation or follicular dynamics in mares treated with a GnRH analogue.

OBJECTIVE

To evaluate the effects of therapeutic and supratherapeutic periovulatory doses of firocoxib on ovulation and follicular dynamics in mares.

MATERIALS AND

METHODS

Seventy cycling mares were randomly assigned to receive firocoxib at 0.1 mg/kg (n = 27), firocoxib at 0.3 mg/kg (n = 22), or no treatment (control; n = 21). Treatments were initiated on Day 0, defined as the day of ovulation induction with a GnRH analogue administered intramuscularly, with firocoxib administered intravenously on Day 0 and Day 1 (24 h apart). Follicular diameter and ovulation timing were assessed by transrectal ultrasonography.

RESULTS

All mares ovulated within 72 h after ovulation induction, with no ovulatory failures or hemorrhagic anovulatory follicles. Time to ovulation did not differ among groups (P > 0.05). Dominant follicle diameter on Days -2 and -1 and percentage follicular growth between these days were similar across treatments (P > 0.05).

CONCLUSIONS

Periovulatory administration of firocoxib, even at supratherapeutic doses, did not appear to impair induced ovulation or follicular development in mares under the conditions of this study.