Morphologic stages of the equine embryo proper on days 17 to 40 after ovulation.
Abstract: To describe the gross and histologic changes that develop in the equine embryo proper (ie, the portion of the embryo that becomes the fetus) from days 17 to 40 after ovulation and to compare the external features of equine embryos with those of porcine, ovine, and human embryos. Methods: 34 embryos collected from mixed-breed pony mares. Methods: External features for each embryo proper, including length, number of branchial arches, growth of appendages, face and head features, and body features, were examined, using a dissecting microscope, for embryos collected on days 17 to 40. Internal features were histologically examined by serially sectioning embryos collected on days 20 to 35. Results: Number of embryos recovered for each day ranged from 1 to 5. The initial detection of features was not related closely to age; typically, the first attainment of a given body length or characteristic varied over a 3-day period among embryos. Similarly, the period during which individual characteristics for a given Carnegie stage were attained ranged from 3 to 6 days. Age at first appearance of a characteristic was greater for equine embryos than ages reported for ovine and porcine embryos but less than for human embryos. Indicators of age included number of pairs of branchial arches, all limb buds present, retinal pigmentation, and prominence of the pontine flexure. Conclusions: No embryologic structures or changes were found that could be considered unique to equine embryos on days 17 to 40 after ovulation.
Publication Date: 2001-09-19 PubMed ID: 11560260DOI: 10.2460/ajvr.2001.62.1358Google Scholar: Lookup
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Comparative Study
- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.
This research study examined the physical and tissue changes in equine (horse) embryos from days 17 to 40 after ovulation, comparing features with those of pig, sheep, and human embryos. The study found the presence and development of features varied among the embryos, and that certain characteristics emerged in equine embryos sooner or later than in other species.
Research Methodology
- The study analysed 34 embryos from mixed-breed pony mares from 17 to 40 days after ovulation.
- External features including length, number of branchial arches (gill arches), growth of appendages, facial and head features, and body characteristics were examined under a dissecting microscope.
- Internal characteristics were inspected histologically (microscopic anatomy) by sectioning the embryos collected from 20 to 35 days after ovulation.
Research Findings
- The number of embryos recovered for each day ranged from 1 to 5.
- The appearance of features was not closely related to age, instead, the first appearance of a specific body length or characteristic varied over a period of 3 days amongst the embryos studied.
- The study noticed that the timescale for individual characteristics for a given “Carnegie stage” (a system used to stage human embryonic development) varied, ranging from 3 to 6 days.
- The first appearance of characteristics was found to be greater for equine embryos than for ovine (sheep) and porcine (pig) embryos but was less than for human embryos. Characteristics aiding in Aging included the number of pairs of branchial arches, the presence of all limb buds, retinal pigmentation, and the prominence of the pontine flexure (a bend in the developing brain).
Conclusions
- Overall, no physical structures or changes were found that could be considered unique to equine embryos on days 17 to 40 after ovulation. The findings indicate that while there are variations in the timing of development, the embryonic stage characteristics hold similarities across the species examined.
Cite This Article
APA
Acker DA, Curran S, Bersu ET, Ginther OJ.
(2001).
Morphologic stages of the equine embryo proper on days 17 to 40 after ovulation.
Am J Vet Res, 62(9), 1358-1364.
https://doi.org/10.2460/ajvr.2001.62.1358 Publication
Researcher Affiliations
- Department of Animal Health and Biomedical Sciences, School of Veterinary Medicine, University of Wisconsin, Madison 53706, USA.
MeSH Terms
- Animals
- Embryonic and Fetal Development / physiology
- Female
- Horses / anatomy & histology
- Horses / embryology
- Humans
- Pregnancy
- Sheep
- Swine
Citations
This article has been cited 2 times.- Handschuh S, Okada CTC, Walter I, Aurich C, Glösmann M. An optimized workflow for microCT imaging of formalin-fixed and paraffin-embedded (FFPE) early equine embryos. Anat Histol Embryol 2022 Sep;51(5):611-623.
- Rigoglio NN, Barreto RS, Favaron PO, Jacob JC, Smith LC, Gastal MO, Gastal EL, Miglino MA. Central Nervous System and Vertebrae Development in Horses: a Chronological Study with Differential Temporal Expression of Nestin and GFAP. J Mol Neurosci 2017 Jan;61(1):61-78.
Use Nutrition Calculator
Check if your horse's diet meets their nutrition requirements with our easy-to-use tool Check your horse's diet with our easy-to-use tool
Talk to a Nutritionist
Discuss your horse's feeding plan with our experts over a free phone consultation Discuss your horse's diet over a phone consultation
Submit Diet Evaluation
Get a customized feeding plan for your horse formulated by our equine nutritionists Get a custom feeding plan formulated by our nutritionists
