Hostname: page-component-78c5997874-xbtfd Total loading time: 0 Render date: 2024-11-17T20:04:09.589Z Has data issue: false hasContentIssue false
  • English
  • Français

Factors influencing placental and fetal development in the mare: important considerations for the selection of embryo recipients

Published online by Cambridge University Press:  27 February 2018

S Wilsher  and
W R Allen
S Wilsher
Affiliation:
University of Cambridge, Department of Clinical Veterinary Medicine Equine Fertility Unit, Mertoun Paddocks Newmarket, Suffolk CB8 9BH, UK
W R Allen
Affiliation:
University of Cambridge, Department of Clinical Veterinary Medicine Equine Fertility Unit, Mertoun Paddocks Newmarket, Suffolk CB8 9BH, UK
Get access

Extract

In mammals the placenta is the vehicle for nutritional and gaseous exchange between the maternal and fetal circulations during pregnancy. The allantochorionic placenta of equids is classified as non–deciduate, non–invasive, epitheliochorial and diffuse and, as such, equine placentation demands fetomaternal interdigitation over the entire endometrial surface to optimise fetal development in utero. Any shortcomings are reflected by slower growth and delayed maturation of the fetus.

This requirement for an unabbreviated area of placental attachment is emphasised by the inability of mares to carry twin conceptuses to term due to simple competition between the two placentae for the limited area of endometrium which results in progressive starvation of one or both fetuses (Jeffcott and Whitwell, 1973). In addition, age–related chronic degenerative changes in the mare's endometrium (endometrosis) may compromise the uterine environment during pregnancy and Bracher et al. (1996) showed a close relationship between the health of the endometrium, the normality of structure and the density of the microcotyledons on the surface of the allantochorion, and fetal weight.

Type
Research Article
Information
BSAP Occasional Publication , Volume 32: Emerging Equine Science , 2004 , pp. 87 - 89
Copyright
Copyright © British Society of Animal Production 2014

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Bracher, V., Mathias, S and Allen, W.R. (1996). Influence of chronic degenerative endometritis (endometrosis) on placental development in the mare. Equine Veterinary Journal 28: 180–188.Google Scholar
Finocchio, E.J. (1986). Race performance and its relationship to birthrank and maternal age. Proceedings of the American Association of Equine Practitioners 31: 571–578.Google Scholar
Jeffcott, L.B. and Whitwell, K.E. (1973). Twinning as a cause of foetal and neonatal loss in the Thoroughbred mare. Journal of Comparative Pathology 83: 91–105.Google Scholar
Hintz, H.F ., Hintz, R.L. and Van Vleck, L.D. (1979). Growth rate of thoroughbreds. Effect of age of dam, year and month of birth, and sex of foal. Journal of Animal Science 48: 480–487.Google Scholar
Tischner, M. and Klimszak, M. (1989). Development of Polish pony foals born after transfer to large mares. Journal of Reproduction and Fertility Supplement 8: 62–63.Google Scholar
Walton, A and Hammond, J. (1938). The maternal effects on growth and conformation in Shire horse–Shetland crosses. Proceedings of the Royal Society, Series B.125: 311–335.Google Scholar