Speed of in vitro embryo development affects the likelihood of foaling and the foal sex ratio.
Abstract: The success of invitro embryo production (IVEP) in horses has increased considerably during recent years, but little is known about the effect of the speed of invitro embryo development. Blastocysts (n=390) were produced by intracytoplasmic sperm injection of IVM oocytes from warmblood mares, cryopreserved, thawed and transferred into recipient mares on Days 3, 4, 5 or 6 after ovulation. The time required for invitro-produced (IVP) embryos to reach the blastocyst stage was recorded (Day 7 vs Day 8). The likelihood of foaling was affected by the speed of invitro embryo development and recipient day after ovulation at transfer. The odds ratio for foaling was ~0.63 for transfer of Day 8 (46%) compared with Day 7 (56%) IVP blastocysts. The highest likelihood of pregnancy (72%) and foaling (60%) was observed when IVP blastocysts were transferred to recipient mares on Day 4 after ovulation. Finally, the sex (colt:filly) ratio was higher after transfer of Day 7 (71%:29%) than Day 8 (54%:46%) IVP blastocysts, suggesting that the speed of embryo development is sex dependent. In conclusion, the speed of invitro embryo development in our IVEP system affects the likelihood of foaling and the sex of the foal.
Publication Date: 2020-03-17 PubMed ID: 32172777DOI: 10.1071/RD19298Google Scholar: Lookup
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- Comparative Study
- Journal Article
Summary
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The research article discusses the effect of the rate of in vitro embryo development on the probability of successful foaling and the sex ratio of the foal in horses.
Study Overview
- The research focused on in vitro embryo production (IVEP) in horses. The embryos were produced through a process called Intracytoplasmic Sperm Injection (ICSI) on In Vitro Maturation (IVM) oocytes obtained from warmblood mares.
- The embryos produced in vitro were then frozen and thawed before being transferred to recipient mares on days 3, 4, 5, or 6 after ovulation.
- Two categories were established to track the speed at which embryos reached the blastocyst stage: Day 7 and Day 8.
Findings
- The investigation revealed that the time required for the embryos to reach the blastocyst stage significantly influenced the likelihood of a successful birth.
- The odds ratio for successful foaling was approximately 0.63 for the transfer of Day 8 blastocysts compared to the transfer of Day 7 blastocysts. In numerical terms, the success rate was 46% for blasts transferred on Day 8 compared to 56% on Day 7.
- Additionally, the researchers noted a higher likelihood of pregnancy (72%) and successful foaling (60%) when the blastocysts were transferred to the recipient mares on Day 4 post-ovulation.
Impact of Embryo Development Speed on Sex Ratio
- The research also uncovered that the speed of embryo development influenced the sex of the foals. The sex ratio (colt:filly) was higher when Day 7 embryos were transferred (71%:29%) compared to when Day 8 embryos were transferred (54%:46%).
- This finding implies that the speed of in vitro embryo development is sex-dependent.
Conclusion
- In summary, the speed of invitro embryo development in the IVEP system impacts both the likelihood of successful foaling and the sex ratio of the foal. Hence, this study provides critical insights for the optimization of techniques used in producing horse embryos in vitro.
Cite This Article
APA
Claes A, Cuervo-Arango J, Colleoni S, Lazzari G, Galli C, Stout TA.
(2020).
Speed of in vitro embryo development affects the likelihood of foaling and the foal sex ratio.
Reprod Fertil Dev, 32(5), 468-473.
https://doi.org/10.1071/RD19298 Publication
Researcher Affiliations
- Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 112, 3584CM Utrecht, The Netherlands; and Corresponding author. Email: a.claes@uu.nl.
- Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 112, 3584CM Utrecht, The Netherlands.
- Avantea, Laboratory of Reproductive Technologies, Via Porcellasco, 7/F, 26100 Cremona CR, Italy.
- Avantea, Laboratory of Reproductive Technologies, Via Porcellasco, 7/F, 26100 Cremona CR, Italy; and Fondazione Avantea, Via Cabrini, 12 26100 Cremona CR, Italy.
- Avantea, Laboratory of Reproductive Technologies, Via Porcellasco, 7/F, 26100 Cremona CR, Italy; and Fondazione Avantea, Via Cabrini, 12 26100 Cremona CR, Italy.
- Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 112, 3584CM Utrecht, The Netherlands.
MeSH Terms
- Animals
- Animals, Newborn
- Blastocyst / physiology
- Embryo Culture Techniques / veterinary
- Embryo Transfer / veterinary
- Female
- Horses / physiology
- In Vitro Oocyte Maturation Techniques / veterinary
- Live Birth / veterinary
- Male
- Pregnancy
- Retrospective Studies
- Sex Ratio
- Sperm Injections, Intracytoplasmic / veterinary
- Time Factors
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