Ovarian response to P4‐PGF‐FSH treatment in Suffolk sheep and P4‐PGF‐PMSG synchronization in cross‐bred ewes, for IVD and ET protocol

Abstract

Background:The success of an embryo transfer protocol in sheep depends on many factors, but the choice of drugs for the desired superovulation as well as the conception rate (CR) are most essential. Reproductive activity in sheep is characterized by a seasonality influenced by several factors such as photoperiod, latitude, temperature, nutrition and breed. Reproductive seasonality and nutritional condition are the main factors that influence embryo production in sheep. In sheep, some anatomical peculiarities limit the application of traditional reproductive biotechnologies used in cattle. Objectives:The aim of this study was to conclude on the effectiveness of a wider on farm in vivo embryo transfer development programme in Suffolk sheep by streamlining hormone therapies and optimizing technique.Methods: A total number of 60 sheep and three rams were included in this study, divided into two groups (receptors and donors). Donor Suffolk sheep were treated for superovulation using the P4-PGF-FSH multiple ovulation embryo transfer (MOET) protocol, while the cross-bred recipients' group was synchronized with P4-PGF-PMSG.Results: On the first day after superovulation, all ovaries had more than five dominant follicles, while corpora lutea were later observed in 83.3% sheep. The recovery rate was 83.3%, while 72.9% embryos were transferable. Embryos were transferred directly into recipients. Fertility after 30 days was 68.57%, lambing rate was 91.6% and CR was 62.85%. This study showed that veterinary drugs (P4, FSH, LH, PMSG, PGF) used for superovulation optimized by us were capable of producing by this improved technique the optimization of the reproduction indices at embryo-transfer (ET) and to be able to be used successfully. Conclusions:The application of an MOET protocol has a positive effect in the production of in vivo embryo production (IVD) embryos in Suffolk sheep and can guarantee the success of embryo transfer activity to ewes with lower genetic merit. Our research aimed at representing a model for sheep farms for a rapid improvement of productive traits.

Strategies to improve cervical relaxation, ovarian response, and embryo yield in sheep undergoing non-surgical embryo recovery

“…In the present study, CL count was higher compared to other studies in sheep that found an average of 7 (Lagares et al, 2021) to 9 (Ciornei et al, 2022) CL / ewe using the same commercial formulation of pFSH and doses between 250 to 500 IU.…”

“…response in approximately 90% of animals, as observed in studies of D' Alessandro et al (1996) and Cordeiro et al (2003). This study found a similar or even higher mean CL count (10.1-13.5/ewe) with reduced doses of pFSH (250-400 IU), in comparison to other studies using 500 or 750 IU (8.3-9.1/ewe) Ciornei et al, 2022). Furthermore, it confirms that a better SOV response is directly related to a greater number of recovered structures.…”

Embryo production and transplantation in non‐breeding season of meat sheep breeds by stimulating superovulation with different follicle‐stimulating hormone preparations

“…Similarly, several researchers such as Donaldson et al (1986), Nowshari et al (1995), Boscos et al (2002), found that a low‐LH:FSH preparation may be better for follicle development and obtaining more embryos transferring. On contrary, other researchers showed that a responding donor can produce an average of 8–12 embryos (limit from 1 to 30) depending on the breed, time of year and condition of the animal embryos (Ciornei et al, 2022; Ghosh et al, 2017; Menchaca et al, 2009). In our study, the number of corpora lutea per donor averaged 12.3 ± 0.87 for both treatment regimens, which is also at the upper limit of performance.…”

“…The main factor of donors' response to superovulation is gonadotropin, which directly affects embryos recovery number from one donor (Pérez-Sandoval et al, 2019). Anterior pituitary gland produces FSH preparations and also it contains other biologically active substances such as LH, the amount of FSH and LH and their activity may vary depending on animal breed and different preparations (Braileanu et al, 1998;Ciornei et al, 2022;Donaldson et al, 1986;Luna-Palomera et al, 2019). In our present study, two follicle-stimulating preparations (Folltropin-V and FSH-P) were used to stimulate superovulation in Charolais and Ile-de-France ewes.…”

Embryo transfer of dorper breed to Mongolian sheep

“…Since ET in sheep is a well-known but insufficiently applied reproductive biotechnology. Therefore, there has been a need for an optimization and a continuous improvement of the techniques (Ciornei et al, 2022). Hence, the main objective of this study was to evaluate the conception rate obtained after ET in Mongolian sheep.…”