NonSurgical Embryo Recovery from Estrus-Synchronized or Superovulated Morada Nova Ewes: A Feasible Strategy for Sheep Embryo Banking

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

“…In the ewes of the present study, only 60% (G‐9 SOV ) and 67% (G‐12 SOV ) of all recovered structures were viable embryos. These proportions are similar to those reported in previous studies using the same mating strategy in Morada Nova (G‐9 SOV , 60.0% and G‐12 SOV , 70.5%, respectively; Arrais et al., 2021) and Lacaune ewes (G‐9 SOV , 62.7%; Figueira, Alves, Maia, Souza‐Fabjan, Batista, Morais, et al., 2020) superovulated in the same superovulatory pFSH regimen (133 mg of pFSH in decreasing daily doses). In another study, Morada Nova ewes had 46.9% (68/49) of viable embryos after 14 days of P 4 priming and 133 mg of pFSH, followed by laparoscopic insemination performed 50 hr after device removal (Brasil et al., 2016).…”

“…The present study confirmed the suitability of NSER for use in superovulated Morada Nova ewes (Arrais et al., 2021). Superovulated Morada Nova ewes that underwent oestrus synchronization with progesterone‐releasing device for 12 days produced more viable embryos and had a higher proportion of blastocysts than the ewes pre‐treated with progesterone for 9 days.…”

“…Based on the ultrasonographic detection of CL, 80.5% of viable embryos were recovered from ewes with ≥10 Cl after the superovulatory treatment (48% of flushed ewes). While for conservation purposes, embryo recovery can be conducted even in poor responders or oestrus‐synchronized, non‐superovulated ewes (Arrais et al., 2021), commercial multiple ovulation and embryo transfer (MOET) programmes require eliminating the collections from animals that do not contribute significantly to a final viable embryo yield. As indicated earlier by Oliveira, Ribeiro, et al.…”

“…NSER was performed 6–7 days after the onset of oestrus. Cervical assessment, anaesthetic desensitization, clipping and cervical retraction were also performed as previously described (Arrais et al., 2021). After retraction, the Hegar dilators (size 3–4) were used to traverse the cervix.…”

“…While the period of progesterone or progestin exposure in Merino (5–14 days, Menchaca et al., 2010) and Santa Inês ewes (6.5 vs 14.5 days, Oliveira et al., 2020) had a limited effect on in vivo embryo production, the 9‐day treatment with medroxyprogesterone acetate was associated with better outcomes compared with the short‐term (6 days) protocol in Lacaune ewes (Figueira, Alves, Maia, Souza‐Fabjan, Batista, Morais, et al, 2020). Results of a preliminary study comparing embryo yields in superovulated and oestrus‐synchronized, non‐superovulated Morada Nova ewes subjected to progesterone‐based oestrus synchronization protocols of varying durations (6, 9 or 12 days) showed that the 9‐ and 12‐day protocols resulted in better embryo recovery rates than the 6‐day regimen (Arrais et al., 2021), but a confirmatory trial is still needed.…”