Ovarian Structures during the Estrous Cycle and Early Pregnancy in Ewes1

Abstract

The development of ovarian follicular and luteal structures during the estrous cycle and early pregnancy in ewes was examined. Ewes were treated with prostaglandin F2 alpha to induce estrus; they were placed with either two fertile or two vasectomized rams and observed for estrus twice daily. Beginning at estrus (Day 0), ovaries were scanned for CL and for follicles > or = 2 mm by transrectal ultrasonography daily for the first 25 days of pregnancy (PREG, n = 17 ewes) or until Day 8 of the second estrous cycle (CYC, n = 15 ewes). Jugular blood samples were collected at ultrasonography and on Days 30, 35, and 40 of gestation for RIA of progesterone and estradiol-17 beta. Total follicles (17.6 +/- 1.3), number of follicles > or = 4 mm in diameter (11.3 +/- 0.6), and number of follicles that became the largest during the first 16 days of pregnancy or the first estrous cycle (4.9 +/- 0.3) did not differ between PREG and CYC ewes. Number of newly detected follicles each day and difference in mean diameter between the largest two follicles and all other follicles were similar between PREG and CYC ewes until luteal regression. At that time, difference in diameter between the largest two follicles and all other follicles increased in CYC ewes in parallel with estradiol-17 beta in serum. Mean concentrations of progesterone in serum were higher in PREG than in CYC ewes (2.4 +/- 0.1 vs. 2.0 +/- 0.1 ng/ml; p < 0.05) before onset of luteal regression, but mean areas of CL did not differ.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of maternal environment on the number of transferable embryos obtained in response to superovulatory FSH treatments in ewes

“…Ultrasonographies were realized using a 7.5 MHz linear-array probe fitted to an Aloka SSD 500 (Ecotron, Madrid, Spain), as described by Schrick et al [11] and validated in our laboratory by Gonzalez-Bulnes et al [12].…”

Respostas endócrinas e ovarianas associadas com o folículo dominante da primeira onda folicular em ovelhas sincronizadas com CIDR ou PGF2alfa

“…As concentrações continuaram aumentando progressivamente do quinto (3,43 ± 0,33 ng/mL) ao nono dia (4,91 ± 0,33 ng/mL), evidenciando diferença estatís-tica significativa (p<0,0001) entre os dias do ciclo estudados. Valores inferiores foram reportados por Schrick et al (1993), devido principalmente ao tipo de ensaio utilizado.…”

“…Também foram obtidos por Scaramuzzi et al (1993) e Schrick et al (1993) aumentos nas concentrações de E 2 plasmático nos dias três a oito; entretanto, foram descritos aumentos significativos por nos dias seis a nove do ciclo estral, o que pode estar ligado, estreitamente, ao desenvolvimento das ondas de crescimento folicular. Os resultados corroboram os achados de Kouskoura et al (1995), os quais mostraram que a sincronização de estro acompanhada da administração de eCG (8 UI/kg), na retirada do implante de P 4 (375 mg), em ovelhas Friesland, Chios, Serres e Karagouniki, provocou aumentos nas concentrações plasmáticas de E 2 nas quatro horas seguintes e, a partir daí, diminuíram gradualmente, o que revelou significativas diferenças estatísticas entre raças, sugerindo também que o uso de menor dosagem de eCG, no momento da retirada do progestágeno, permite melhor e mais precisa sincronização de estro e ovulação.…”

Applications of ultrasonography in ruminants (II): Female reproductive system - A review

“…Στα πρόβατα οι παλμοί της καρδιάς των εμβρύων ανιχνεύονται για πρώτη φορά την 1 Η Τ| -23η ημέρα της κυοφορίας (Gareia et ah 1993, Schrick andInskeep 1993), ενώ στις αίγες την 19 η -23 Τ| ημέρα (Martinez et al 1998). Από τα ανατομικά στοιχεία των εμβρύων αυτά που χρησιμοποιούνται συχνότερα για το προσδι ορισμό του σταδίου της κυοφορίας είναι το ΚΓΜ και η ΑΒΔ (Mcincckc -Tillmann and Mcincckc 2007).…”