Medroxyprogesterone Acetate: RESULTS(3)


At the time of sponge removal in treated ewes, the last follicular wave before ovulation contained ovulatory follicles in all ewes studied. Of all follicles reaching >5 mm in diameter in this wave. 85% (11/13) and 73% (11/15) ovulated in the treatment and control groups, respectively (P > 0.05). The penultimate wave contained ovulatory follicles in five treated ewes but in only two control sheep. In the penultimate follicular wave. 70% (7/10) and 21% (3/ 14) of follicles >5 mm in size were ovulatory in the treated and control ewes, respectively (P < 0.05). In addition, one treated ewe had a follicle that emerged in the follicular wave before the penultimate wave (Day -2 before PGF2J and it ovulated 11 days after emergence. One treated ewe ovulated a follicle from a wave that emerged >3 days before PGF2c, and the time elapsed from emergence to ovulation was >12 days. Finally, one treated ewe had an ovulatory follicle that emerged in each of the two waves before the penultimate wave. buy zyban

None of the characteristics of follicle growth for ovulatory follicles in the last wave before ovulation detected after MAP treatment of treated ewes differed between the treated and control ewes (Table 3). In both groups of ewes, ovulatory follicles in the penultimate follicular wave emerged approximately 3 days earlier than ovulatory follicles in the final wave before ovulation. Ovulatory follicles in the penultimate wave in the treated ewes had a significantly longer growing phase (5.1 ± 0.5 vs. 3.0 ± 0.0 days) but a shorter static phase (2.7 ± 0.6 vs. 5.0 ± 1.0 days) compared with the control ewes (P < 0.05).

TABLE 3. Characteristics of ovulatory antral follicles (growing to >5 mm diameter; means ± SEM) originating from the final or penultimate follicular wave before ovulation (posttreatment).*
Table3Effects of a 6-Day Treatment-4
* In 7 Western white-faced ewes that received PGF2a injection on — Day 8 and a progestogen (MAP) sponge from — Days 8 to 14 after ovulation, and in 7 control (untreated) white-faced ewes (experiment 1). Day 0 = Day of PGF2a injection and insertion of MAP sponges in treated ewes.
AB Means with different letter superscripts are significantly different (P < 0.05) between the final and penultimate waves for treated ewes; CD between the final and penultimate waves for control ewes; and ab between treated and control ewes for the penultimate follicular wave.