Follicular wave emergence in Santa Inês ewes subjected to long-term, progesterone-based estrous synchronization protocols at different times of the year

Oliveira, M. E. F.; Ayres, H.; Oliveira, Luís Guilherme de; Oba, Eunice; Kridli, Rami T.; Bartlewski, Pawel M.; Fonseca, J. F.; Bicudo, Sony Dimas; Vicente, W. R. R.

doi:10.1016/j.anireprosci.2016.09.008

Cited by 11 publications

(5 citation statements)

References 23 publications

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“…Since the numbers of antral follicles at the time of the first and sixth pFSH dose did not vary between the two groups of ewes (G‐12 SOV and G‐9 SOV ), the difference in ovulation rates is most likely related to follicular responsiveness to the pre‐ovulatory secretion of LH (Veiga‐Lopez et al., 2006). Circulating progesterone (P 4 ) concentrations decline gradually from one day after progesterone‐releasing intravaginal device insertion until the day of its removal (Oliveira et al., 2016). It is, therefore, possible that circulating P 4 concentrations during the pFSH treatment (i.e.…”

Section: Discussionmentioning

confidence: 99%

A study of the factors affecting embryo yields and quality in superovulated Morada Nova ewes that underwent non‐surgical uterine flushing

Oliveira

Arrais

Mello

et al. 2022

Reprod Domestic Animals

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The present study compared the outcomes of in vivo embryo production in Morada Nova ewes subjected to either 9‐day (G‐9SOV, n = 21) or 12‐day (G‐12SOV, n = 21) progesterone (P4)‐based estruses synchronization protocol coupled with superovulatory treatment with decreasing doses of porcine follicle‐stimulating hormone (133 mg of pFSH given over 3 days). Non‐surgical embryo recovery (NSER) was performed 6–7 days after the onset of oestrus. Total antral follicle count doubled from the first to the sixth pFSH dose in both groups (p < .05). Oestrus responses did not vary between the two groups of animals (95.2%). Corpora lutea (CL) were detected in 85.0% and 60.0% of ewes that previously manifested oestrus behaviour in G‐9SOV and G‐12SOV respectively. NSER was successfully completed in 86.2% of ewes that had CL (p > .05). The mean number of CL per ewe/successfully flushed donor ewe was greater (p < .05) in G‐12SOV (12.3 ± 1.7/12.1 ± 1.9) than in G‐9SOV (7.9 ± 1.4/8.2 ± 1.6). Mean numbers of retrieved blastocysts and viable embryos were greater (p > .05) in G‐12SOV (5.8 ± 1.9 and 3.7 ± 1.7) than G‐9SOV (3.5 ± 1.1 and 0.8 ± 0.3 respectively). The total follicle count (all follicles ≥2 mm in diameter) at the sixth pFSH dose (at P4‐device removal) was positively correlated (p < .05) with the number of CL (r = .95) and viable embryos (r = .91) in G‐12SOV. The ewes with ≥10 Cl (48% of all flushed donors) yielded 80.5% of viable embryos. In summary: (a) Morada Nova ewes from G‐12SOV group had better superovulatory responses compared with G‐9SOV group; (b) total follicle count at the last pFSH dose was a good predictor of superovulatory responses only in the ewes primed with P4 for 12 days; and (c) animals with ≥10 ovulations are main contributors to viable embryo production in Morada Nova ewes.

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Section: Discussionmentioning

confidence: 99%

A study of the factors affecting embryo yields and quality in superovulated Morada Nova ewes that underwent non‐surgical uterine flushing

Oliveira

Arrais

Mello

et al. 2022

Reprod Domestic Animals

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“…This study was conducted in Jaboticabal, SP, Brazil (latitude: 21°15′18″S, longitude 48°19′19″W) from July to October (period of lengthening day lengths) and it utilized 24 sexually mature Santa Inês ewes, 2–3 years old, weighing 35–45 kg and kept under intensive management system with unlimited access to mineral salt licks, water and corn silage, and balanced feed rations (~200 g/animal/day). During the period of lengthening day lengths in southern Brazil, approximately 55% of Santa Inês ewes exhibit recurrent ovulatory cycles (Oliveira, Ayres, Oliveira, Barros, et al., ; Oliveira, Ayres, Oliveira, Oba, et al., ).…”

Section: Methodsmentioning

confidence: 99%

Assessing the usefulness of B‐mode and colour Doppler sonography, and measurements of circulating progesterone concentrations for determining ovarian responses in superovulated ewes

Oliveira

Ribeiro

Rodriguez

et al. 2018

Reprod Domestic Animals

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The main goal of this study was to assess the usefulness of two imaging modalities, namely the B-mode and colour Doppler sonography, and serum progesterone (P ) concentrations for determining the ovarian response in superovulated ewes. Twenty-four sexually mature Santa Inês ewes underwent the superovulatory treatment consisting of eight injections of porcine FSH (total dose of 200 or 133 or 100 mg; n = 8 ewes/total dose) given at 12-hr intervals and initiated 48 hr before CIDR (Pfizer Inc., Auckland, New Zealand) removal. Six days after natural mating, the ovaries of all donor ewes were visualized and examined with transrectal ultrasonography and then with videolaparoscopy to identify and enumerate corpora lutea (CL) and luteinized unovulated follicles (LUFs). Jugular blood samples were collected just prior to ovarian examinations. The total number of CL (r = .78 and 0.83, p < .0001) and LUFs (r = .74 and 0.90, p < .0001) enumerated using the B-mode and colour Doppler ultrasonographic technique, respectively, were correlated with that ascertained by videolaparoscopy. Circulating concentrations of P were related directly to the number of healthy CL (r = .73, p = .0002) and inversely to the number of prematurely regressing CL (r = -.46, p = .03), but the accuracy of predicting the number of short-lived CL with serum P concentrations was very poor. The present results indicate that ultrasonographic imaging and serum P measurements on the day of embryo recovery are useful indicators of total/normal CL numbers and both ultrasonographic techniques can be used to quantify LUFs in superovulated ewes.

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“…The primary factor responsible for the variability in ovarian responses to any superovulation treatment is the ovarian status (the number and size of the antral follicles and CL on the ovaries) at the onset of an exogenous hormonal regimen. Furthermore, synchronization with follicular wave emergence has a major impact on the ovarian response to superovulatory protocols in sheep [ 72 , 73 ]. In sheep, a follicular wave is defined as the emergence or growth of 1–3 follicles from a pool of small follicles (2–3 mm in diameter) on the ovary, reaching >5 mm in diameter before regression (anovulatory wave) or ovulation (ovulatory wave).…”

Section: Factors Affecting Outcomes Of Superovulationmentioning

confidence: 99%

Towards Improving the Outcomes of Multiple Ovulation and Embryo Transfer in Sheep, with Particular Focus on Donor Superovulation

Khan

Jamal

et al. 2022

Veterinary Sciences

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Considerable improvements in sheep multiple ovulation and embryo transfer (MOET)protocols have been made; however, unlike for cattle, MOET is poorly developed in sheep, and thus has not been broadly applicable as a routine procedure. The tightly folded nature of the ewe cervix, the inconsistent ovarian response to various superovulatory treatments, and the requirement of labor to handle animals, particularly during large-scale production, has limited the implementation of successful MOET in sheep. Moreover, several extrinsic factors (e.g., sources, the purity of gonadotrophins and their administration) and intrinsic factors (e.g., breed, age, nutrition, reproductive status) severely limit the practicability of MOET in sheep and other domestic animals. In this review, we summarize the effects of different superovulatory protocols, and their respective ovarian responses, in terms of ovulation rate, and embryo recovery and transfer. Furthermore, various strategies, such as inhibin immunization, conventional superovulation protocols, and melatonin implants for improving the ovarian response, are discussed in detail. Other reproductive techniques and their relative advantages and disadvantages, such as artificial insemination (AI), and donor embryo recovery and transfer to the recipient through different procedures, which must be taken into consideration for achieving satisfactory results during any MOET program in sheep, are also summarized in this article.

show abstract

Follicular wave emergence in Santa Inês ewes subjected to long-term, progesterone-based estrous synchronization protocols at different times of the year

Cited by 11 publications

References 23 publications

A study of the factors affecting embryo yields and quality in superovulated Morada Nova ewes that underwent non‐surgical uterine flushing

A study of the factors affecting embryo yields and quality in superovulated Morada Nova ewes that underwent non‐surgical uterine flushing

Assessing the usefulness of B‐mode and colour Doppler sonography, and measurements of circulating progesterone concentrations for determining ovarian responses in superovulated ewes

Towards Improving the Outcomes of Multiple Ovulation and Embryo Transfer in Sheep, with Particular Focus on Donor Superovulation

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