Embryo transport through the mare’s oviduct depends upon cleavage and is independent of the ipsilateral corpus luteum.
Abstract: Two experiments were conducted using 14 mares. In Exp. 1, mares were inseminated with semen treated with TEPA, which, in other species, has been shown to lead to an arrest in ovum cleavage at 2--4 cells. The oviducts and/or uterus were then flushed 7--10 days after ovulation in 6 mares (Group A) or 2--6 days after ovulation in 5 mares (Group B). Fresh eggs were found in the oviduct flushes of 5 Group A and 5 Group B mares: 9 of the 10 eggs appeared to have cleaved, but none had developed beyond 16-cells. Seven eggs contained spermatozoa and 3 of 4 eggs from each group showed evidence of fertilization when examined ultrastructurally. Group A mares had thus retained fertilized eggs in the oviduct beyond the time at which they would normally have entered the uterus (6 days), indicating that development beyond at least the 2- to 4-cell stage is necessary for normal transport. In Exp. 2, 5 attempts were made to recover the embryo within 4 days of ovulation and transfer it to the contralateral oviduct. A single pregnancy resulted, indicating that a unilateral interaction with the corpus luteum was not necessary for the transport of the embryo to the uterus.
Publication Date: 1979-01-01 PubMed ID: 289814
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- Journal Article
Summary
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The research conducted experiments on mares to understand the factors influencing embryo transport through the oviduct. It was discovered that ovum cleavage significantly impacts this process, while the presence of an ipsilateral corpus luteum doesn’t affect it.
Plain Language Overview
The study conducted two experiments on 14 mares to determine what affects the transport of embryos through the mare’s oviduct. It was determined that the splitting of the ovum, or cleavage, plays a critical role, while the presence of a corpus luteum on the same side does not.
Experiment 1
- In the first experiment, a group of mares were inseminated with semen treated with TEPA, a compound known in other species to halt ovum cleavage at the 2-4 cell stage.
- The mares’ oviducts and/or uterus were flushed after ovulation; for six mares this was done 7-10 days after ovulation (Group A) and for five mares this was done 2-6 days after (Group B).
- Fresh eggs were found in oviduct flushes of mares from both groups, most of which appeared to have undergone cleavage, though none had developed beyond 16 cells.
- Most eggs contained sperm and showed evidence of fertilization under ultrastructural examination.
- However, Group A mares retained fertilized eggs in the oviduct beyond the normal time for them to enter the uterus (6 days), indicating that development beyond the 2- to 4-cell stage is essential for normal transport.
Experiment 2
- In the second experiment, attempts were made to recover an embryo within 4 days of ovulation and transfer it to the contralateral oviduct.
- A single pregnancy was achieved, indicating that a unilateral interaction with the corpus luteum is not necessary for embryo transport to the uterus.
Conclusion
- The research suggests that embryo transport in mares highly depends on the cleavage of the ovum. In contrast, the presence of a corpus luteum on the same side as the ovary that produced the oocyte does not have a significant impact on embryo transport.
Cite This Article
APA
Betteridge KJ, Eaglesome MD, Flood PF.
(1979).
Embryo transport through the mare’s oviduct depends upon cleavage and is independent of the ipsilateral corpus luteum.
J Reprod Fertil Suppl(27), 387-394.
Publication
Researcher Affiliations
MeSH Terms
- Animals
- Cleavage Stage, Ovum / physiology
- Corpus Luteum / physiology
- Embryo Transfer / methods
- Embryo Transfer / veterinary
- Fallopian Tubes / physiology
- Female
- Fertilization
- Horses / physiology
- Ovulation
- Pregnancy
- Pregnancy, Animal
Citations
This article has been cited 5 times.- Swegen A. Maternal recognition of pregnancy in the mare: does it exist and why do we care?. Reproduction 2021 May 5;161(6):R139-R155.
- Saint-Dizier M, Schoen J, Chen S, Banliat C, Mermillod P. Composing the Early Embryonic Microenvironment: Physiology and Regulation of Oviductal Secretions. Int J Mol Sci 2019 Dec 28;21(1).
- Binelli M, Gonella-Diaza AM, Mesquita FS, Membrive CMB. Sex Steroid-Mediated Control of Oviductal Function in Cattle. Biology (Basel) 2018 Feb 2;7(1).
- Poitras P, Guay P, Vaillancourt D, Zidane N, Bigras-Poulin M. In vitro viability of cryopreserved equine embryos following different freezing protocols. Can J Vet Res 1994 Oct;58(4):235-41.
- Betteridge KJ, Eaglesome MD, Mitchell D, Flood PF, Beriault R. Development of horse embryos up to twenty two days after ovulation: observations on fresh specimens. J Anat 1982 Aug;135(Pt 1):191-209.
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