Reference

The influences of progestogens and 17

The influences of progestogens and 17.beta.-estradiol on the reproductive performance of the ewe. Alifakiotis, T. A.; Foote, W. C.; Ekre, Cordell D. (Utah State Univ., Logan, Utah, USA). Proc. World Vet. Congr., 20th, Volume 2, 935-40. XX World Vet. Congr., Organ. Comm., Fac. Vet. Med., Aristotelian Univ.: Salonika, Greece. (English) 1975. CODEN: 36BVAH. DOCUMENT TYPE: Conference CA Section: 2 (Hormone Pharmacology) In a study involving 225 cycling ewes, the effects of 3 progestogen treatments, 6.alpha.-chloro-17-hydroxypregna-4,6-diene-3,20-dione acetate (CAP) [302-22-7], orally; Cronolone [2529-45-5] in a pessary; and progesterone (I) [57-83-0] in a silastic rubber implant, were compared to an untreated control group. Two and 0 mg estradiol (II) [50-28-2] (initial) and 2, 1, or 0 mg II (final) were injected at the end of the 14 day progestogen treatment period and 1 cycle length later. No difference was obsd. in synchronization of estrus due to progestogen-route of administration. Ovulation rate was depressed at the 1st following injection of 2 mg. II but not after 1 or 0 mg. II had no effect on the percentage of ewes lambing except when 2 mg was administered at both the initial and final period. Two mg but not 1 mg of final II decreased the conception rate at the 1st estrus bred.

Preovulatory LH release and ovulation in dry and in lactating ewes after progestagen and PMSG treatment during the seasonal anestrum

Preovulatory LH release and ovulation in dry and in lactating ewes after progestagen and PMSG treatment during the seasonal anestrum. Cognie, Y.; Pelletier, J.; Caraty, A. (Cent. Rech. Tours, Inst. Natl. Rech. Agron., Monnaie, Fr.). Ann. Biol. Anim., Biochim., Biophys., 16(4), 529-36 (English) 1976. CODEN: ABABAC. DOCUMENT TYPE: Journal CA Section: 2 (Hormone Pharmacology) Onset of estrus and the time of ovulation was compared in dry ewes and in lactating ewes treated with progestagen fluorogestone acetate (FGA) [2529-45-5]-impregnated vaginal sponges followed by a pregnant mare serum gonadotropin (PMSG) [9002-70-4] injection during the nonsexual season. In other ewes treated in the same way, LH [9002-67-9] release and the age of corpora lutea were studied. The onset of estrus was earlier in dry ewes than in lactating ewes (33.9 vs. 36.7 h, but the interval to estrus and the first ovulations was shorter in the latter than in the former (24.5 vs. 27.5 h); thus in both groups the first ovulations occurred 62.0 h after sponge removal. However, by comparing the no. of ovulations at 72 and 100 h after sponge removal, it was apparent that late ovulations occurred in both groups, with a significant difference (2. 9002-70-4 and 9002-67-9 which are cas registry numbers of chemicals are mentioned.1 vs. 3.4 corpora lutea) in the lactating females only. This may also explain why the mean age of corpora lutea, estd. 100 h after sponge removal, differed between lactating ewes and dry ewes (25.3 vs. 35.0 .+-. 2.0 h). Although LH release was 25% less in lactating than in dry ewes, it seems probable that this cannot explain all the differences between the two groups at the ovarian level. .