Single-dose FSH protocol with 48- or 72-h coasting periods as simplified alternatives for in vitro embryo production in Angus oocyte donor cows.
Single-dose FSH protocols can be as effective as multiple injections for embryo production in cattle, without compromising quality when coasting periods are shortened.
Where it sits
this study against the rest of the gonadorelin (gnrh) corpusSummary and findings
The study evaluated superstimulation protocols prior to follicular aspiration and compared coasting periods on superstimulatory response and in vitro embryo production in Bos taurus cows. A total dose of 160 mg of FSH was administered across four treatment groups. The findings indicated that single-dose FSH protocols were as effective as multiple injections for embryo production.
Abstract
The aim of the present study was to evaluate different superstimulation protocols prior to follicular aspiration and to compare coasting periods on superstimulatory response and in vitro embryo production (IVP) in Bos taurus cows. Donor cows were randomly assigned to one of four treatment groups in a crossover design repeated across four replicates: (1) a negative control (no FSH), (2) a multiple-injection FSH protocol, (3) a single-dose FSH diluted in hyaluronic acid with a 48 h coasting period (MAP48), and (4) a single-dose FSH diluted in hyaluronic acid with a 72 h coasting period (MAP72). In all FSH-treated groups, cows received a total dose of 160 mg of FSH. To ensure that ovum pick-up (OPU) was performed on the same chronological day in all four groups, the initiation of progesterone, GnRH, and FSH treatment in the MAP48 group was delayed by one day, thereby achieving a shorter coasting period without altering the timing of OPU. Ovum pick-up was performed simultaneously in all groups, and recovered cumulus-oocyte complexes (COCs) were evaluated and cultured, followed by in vitro fertilization and culture of presumptive zygotes. Superstimulation with FSH increased the number of viable COC and tended to increase blastocyst production compared with untreated controls. No differences were observed in COC recovery, embryo production, or blastocyst production rates between the multiple FSH protocol and the single-dose (MAP48 or MAP72) protocols, nor between the two coasting periods. Day 7 blastocysts were further analyzed to evaluate embryo quality, including relative gene expression of inner cell mass and trophectoderm markers and total and CDX2-positive cell number. No differences were detected among treatments for any of these variables, suggesting that the day of oocyte collection per se does not affect embryo quality when coasting periods are within the studied range. In conclusion, single-dose protocols of FSH diluted in hyaluronic acid were as effective as multiple FSH injections for IVP in beef cows, and shortening the coasting period from 72 to 48 h did not compromise embryo yield or quality.
Background
This paper addresses the efficiency of different superstimulation protocols for in vitro embryo production in cattle, a critical aspect of reproductive management in livestock. Previous studies have indicated that FSH can enhance ovarian response and embryo yield, but the optimal administration method and timing remain unclear. This study is significant as it explores simplified protocols that could improve reproductive efficiency in beef cattle.
Methods
The study employed a crossover design with four treatment groups: a negative control, a multiple-injection FSH protocol, a single-dose FSH with a 48-hour coasting period, and a single-dose FSH with a 72-hour coasting period. The sample consisted of Bos taurus cows, with a total dose of 160 mg of FSH administered. The primary outcomes measured included COC recovery, embryo production, and blastocyst quality, assessed after ovum pick-up.
Results
Superstimulation with FSH increased the number of viable COC compared to untreated controls. No significant differences were found in COC recovery, embryo production, or blastocyst production rates between the multiple FSH protocol and the single-dose protocols. The study reported that shortening the coasting period from 72 to 48 hours did not compromise embryo yield or quality.
Interpretation
The results suggest that single-dose FSH protocols can be as effective as multiple injections, which may simplify the procedure for practitioners. However, the lack of significant differences in embryo quality and production raises questions about the clinical relevance of the findings. Limitations such as small sample size and specific conditions may affect the generalizability of the results.
Key findings
- 160 mg total dose of FSH administered across treatment groups.
- No differences in COC recovery, embryo production, or blastocyst production rates between multiple FSH protocol and single-dose protocols.
- Superstimulation with FSH increased the number of viable COC compared to untreated controls.
- Blastocyst production tended to increase with FSH treatment compared to controls.
- No differences in embryo quality measures among treatments.
Limitations
- Small sample size may limit generalizability.
- Crossover design may introduce confounding variables.
- Short follow-up period may not capture long-term outcomes.
- No significant differences in embryo quality measures reported.