In:
Reproduction in Domestic Animals, Wiley, Vol. 57, No. 4 ( 2022-04), p. 393-401
Abstract:
The present study compared the outcomes of in vivo embryo production in Morada Nova ewes subjected to either 9‐day (G‐9 SOV , n = 21) or 12‐day (G‐12 SOV , n = 21) progesterone (P 4 )‐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‐9 SOV and G‐12 SOV 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‐12 SOV (12.3 ± 1.7/12.1 ± 1.9) than in G‐9 SOV (7.9 ± 1.4/8.2 ± 1.6). Mean numbers of retrieved blastocysts and viable embryos were greater ( p 〉 .05) in G‐12 SOV (5.8 ± 1.9 and 3.7 ± 1.7) than G‐9 SOV (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 P 4 ‐device removal) was positively correlated ( p 〈 .05) with the number of CL ( r = .95) and viable embryos ( r = .91) in G‐12 SOV . The ewes with ≥10 Cl (48% of all flushed donors) yielded 80.5% of viable embryos. In summary: (a) Morada Nova ewes from G‐12 SOV group had better superovulatory responses compared with G‐9 SOV group; (b) total follicle count at the last pFSH dose was a good predictor of superovulatory responses only in the ewes primed with P 4 for 12 days; and (c) animals with ≥10 ovulations are main contributors to viable embryo production in Morada Nova ewes.
Type of Medium:
Online Resource
ISSN:
0936-6768
,
1439-0531
Language:
English
Publisher:
Wiley
Publication Date:
2022
detail.hit.zdb_id:
2020494-2
SSG:
12
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