The effect of administering a dopamine agonist (Cabergoline) on follicular and luteal development during pro-estrus and estrus in the female greyhound

There were no differences between Cabergoline-treated and control dogs in the duration of pro-estrus or estrus. There was a progressive increase in follicle diameter from the start of pro-estrus when follicles were mainly class F1 to the day of estrus when follicles were mainly class F3. Three days after the start of estrus, the first F-POST follicles were detected. This pattern of development continued and on day 5 the first CLs were detected. By day 9, only CLs were detected. The peak of pre-ovulatory LH was within 3 days of estrus and ovulation was detected in all animals within 3 days of the LH peak. There were no differences in LH concentrations between groups. Plasma prolactin levels varied between animals and were reduced in treated dogs, however, this was not statistically significant (P = 0.12). Plasma progesterone levels were below 1.0 ng/ml before the LH surge and thereafter gradually increased. There were no differences in plasma progesterone concentrations between treated and control dogs. In conclusion these results show that the administration of the dopamine agonist Cabergoline during pro-estrus and estrus did not affect the duration of pro-estrus or estrus or the pattern of follicular and luteal development in female dogs.