Abstract
Two experiments were conducted to investigate the effects of ketoprofen on ovarian function in dairy cows. In experiment I, eight non-milking dairy cows were administered a 0.9% saline solution daily from day 8 (day −3) of ensuing synchronized estrous cycle at 24-h intervals over 4 days (control observation). After an estrous cycle rest, the cows were given the recommended daily therapeutic dose (3 mg/kg, i.m.) of ketoprofen (Ketofen 100; 10%, Merieux/Webster, Australia) from day 8 (day −3) of the synchronized estrous cycle at 24-h intervals over 4 days. All cows received an intramuscular injection of prostaglandin \({\text{F}}_{{{\text{2}}\alpha }}\) (30 mg, Lutalyse) either 6 h before the first treatment of saline solution or 6 h before the first injection of ketoprofen. Ultrasonography of the ovaries was performed daily from the day before (day −4) experimental treatments until day 2 after induced estrus, to monitor the growth of the ovulatory follicle and ovulation, and then on day 9 after estrus to determine the presence and the size of the corpus luteum. In experiment II, five non-milking dairy cows were used in two successive observations. The plasma preovulatory estradiol-17β peak and progesterone concentrations were determined, and ovarian ultrasonography was performed to determine ovulation and corpus luteum development. Results obtained from experiment I showed that the diameter of dominant ovulatory follicle on day of estrus was significantly (p<0.05) higher in saline-treated estrous cycle compared to that of ketoprofen-treated cycles (13.8±1.3 vs 10.9±0.4 mm). Furthermore, by 48 h after standing estrus, ovulation had taken place in seven of eight saline-treated estrous cycles, whereas only three ketoprofen-treated cows had ovulated by 48 h after standing estrus (p<0.05). A significantly (p<0.05) higher mean estradiol-17β peak was observed in ketoprofen-treated estrous cycles at estrus compared to that of the control estrous cycles (experiment II). Additionally, a significant (p<0.05) daily increase in the mean plasma progesterone concentration was observed after ketoprofen treatment beginning from day 0 to 6 of the subsequent estrous cycle (p<0.05). The results of the present study demonstrate that administration of ketoprofen during the pre- and periovulatory period of the estrous cycle in dairy cows impairs final growth of ovulatory follicle, leading to a disturbance in the normal process of ovulation.
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