Early luteal development in Santa Inês ewes superovulated with reduced doses of porcine follicle‐stimulating hormone

Abstract

Contents The aim was to compare the early luteal development in ewes superovulated with different doses of pFSH. Twenty‐nine Santa Inês ewes received a progesterone device (CIDR®) for 8 days. Gonadotrophic treatment started on Day 6: G200 (control, n = 9, 200 mg); G133 (n = 10, 133 mg); and G100 (n = 10, 100 mg of pFSH). On Day 6, all females received eCG (300 IU). B‐mode and spectral Doppler ultrasonography were performed daily during the early luteal phase (Days 11–15) to monitor the development of corpora lutea (CLs; dimensions) and ovarian arteries indices. CLs were also classified as normal or prematurely regressed (PRCL) on Day 15 by videolaparoscopy. Ewes from G100 and G133 showed gradual increase in luteal diameter during the early luteal phase (p < 0.001), whereas G200 animals presented increase from Day 11 to Day 13, and then decrease on Days 14 and 15 (p < 0.001). The G200 females showed greater percentage of PRCL (45.20%) than those of the other groups (p < 0.001). The normal CLs number was greater in G100 than in G133 (p = 0.04), while the PRCL number was greater in G200 than in the other groups (p = 0.03). Resistive index (RI) was greater in G200 than in G100 (p = 0.02). RI was lower in Day 12 than Day 15 (p = 0.02). Pulsatility index (PI) was greater on Days 14 and 15 (p < 0.01). In conclusion, the lowest dose of pFSH (100 mg) can be considered sufficient for an efficient superovulatory response in sheep, producing better CLs development dynamic in early luteal phase and ovarian blood perfusion and smaller number of PRCL than the traditional (200 mg) pFSH dose.

Efeitos da reinserção de dispositivo intravaginal de progesterona sobre parâmetros endócrinos e embrionários em ovelhas superovuladas

“…Although the cascade causing PRCL was possibly already in progress at the time of reinsertion of the P4 device, the strategy tested indicates having either avoided additional PRCL and/or maintain the normal functioning of most CLs. The PRCL is a major cause of naturally occurring subfertility in ruminants (Yaniz et al, 2008) and its occurrence is exacerbated in superovulated animals (Okada et al, 2000;Oliveira et al, 2018;Rodriguez et al, 2019;, and can occur in up to 75% of females (Fukui et al, 1998).…”