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Home / Equine Research Bank / Theriogenology / The effect of age on multiple ovulation rates, multiple preg...
Theriogenology2004; 63(9); 2482-2493; doi: 10.1016/j.theriogenology.2004.09.058

The effect of age on multiple ovulation rates, multiple pregnancy rates and embryonic vesicle diameter in the mare.

Abstract: Numerous and conflicting reports exist regarding factors that may effect mare reproductive performance, in particular multiple ovulation (MO) and its consequences. Sequential ultrasonic examination was used to monitor 3075 ovulations in 1581 mainly Thoroughbred mares to ascertain: whether increasing age is associated with an increase in MO; whether this is counteracted by an increase in embryo mortality (EM) prior to Day 13; and whether this embryonic loss may be associated with small-for-age embryonic vesicles (Days 13/14). Overall ovulation rate was 1.31, MO occurring in 29.3% of cycles. MO incidence significantly (p<0.05) increased with age (20.7% in 2-4-year olds compared to 35.6% in 17-19-year olds). 25.2% of MO were apparent as multiple pregnancies (MP) (40.0% of all pregnancies arising from MO) and 37.8% as single pregnancies (SP) at Days 13/14. Older mares demonstrated significantly (p<0.001) lower pregnancy rates and of those pregnant, significantly (p<0.01) fewer were MP than younger mares. Observation of 1442 embryonic vesicles failed to demonstrate any consistent significant association between age and vesicle size in single ovulating (SO) or MO mares on Days 13/14. We conclude that: (i) increasing age was significantly (p<0.05) associated with increasing incidence of MO; (ii) increasing age was significantly associated with a decreasing incidence of pregnancy/ovulation (p<0.001), and MP (p<0.01), at Days 13/14; (iii) there was no consistent significant association between mare age and vesicle size.
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Publication Date: 2004-12-30 PubMed ID: 15910928DOI: 10.1016/j.theriogenology.2004.09.058Google Scholar: Lookup
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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 explores the effect of age on the multiple ovulation rates, pregnancy rates, and embryonic vesicle diameter in horses. The study concluded that older mares have higher incidences of multiple ovulations but a lower probability of pregnancies resulting from these instances, with no significant correlation to the size of the embryonic vesicle.

Research Methodology

  • The research team conducted a sequential ultrasonic examination on 1581 predominantly Thoroughbred mares, scrutinizing 3075 ovulations.
  • They sought to investigate three main hypotheses: whether increasing age in mares correlates with an increase in multiple ovulation (MO), whether this increase leads to a rise in embryo mortality (EM) before Day 13, and if this embryo loss is connected with smaller embryonic vesicles (on Days 13 and 14).

Key Findings

  • The average ovulation rate from the examinations was 1.31, with MO being observed in roughly 29.3% of all the studied cycles.
  • Significantly, the incidence of MO notably increased with the mares’ age. Compared to the 20.7% MO rate in younger mares aged between 2-4 years, older mares in the age group of 17-19 years displayed a MO rate of 35.6%.
  • Of the observed MO, 25.2% of them evolved into multiple pregnancies (MP). Thus, 40% of all pregnancies that resulted from MO were MPs. Furthermore, 37.8% of these cases resulted in single pregnancies (SP) by Days 13/14.
  • Older mares showed significantly lower pregnancy rates compared to their younger counterparts. Additionally, fewer pregnancies in older mares were confirmed as MPs.
  • A study on 1442 embryonic vesicles showcased no substantial link between the mares’ age and the vesicle’s size, both in multiple and single ovulation cases on Days 13/14.

Conclusions

  • The study concluded that as the mare’s age increases, so does the incidence of MO.
  • Furthermore, there is a significant negative trend between the mare’s age and the occurrence of pregnancy per ovulation, more so among observations of multiple pregnancies.
  • The research did not find any significant and consistent correlation between a mare’s age and the size of the embryonic vesicle.

Cite This Article

APA
Morel MC, Newcombe JR, Swindlehurst JC. (2004). The effect of age on multiple ovulation rates, multiple pregnancy rates and embryonic vesicle diameter in the mare. Theriogenology, 63(9), 2482-2493. https://doi.org/10.1016/j.theriogenology.2004.09.058

Publication

Theriogenology
ISSN: 0093-691X
NlmUniqueID: 0421510
Country: United States
Language: English
Volume: 63
Issue: 9
Pages: 2482-2493

Researcher Affiliations

Morel, Mina C G Davies
  • University of Wales, Institute of Rural Sciences, Aberystwyth, Ceredigion SY233AL, UK. mid@aber.ac.uk
Newcombe, John R
    Swindlehurst, Jennifer C

      MeSH Terms

      • Aging / physiology
      • Animals
      • Embryo, Mammalian / anatomy & histology
      • Embryonic Development
      • Female
      • Fetal Death / veterinary
      • Horses / anatomy & histology
      • Horses / physiology
      • Ovulation
      • Pregnancy
      • Pregnancy, Multiple

      Citations

      This article has been cited 6 times.
      1. Derisoud E, Jouneau L, Dubois C, Archilla C, Jaszczyszyn Y, Legendre R, Daniel N, Peynot N, Dahirel M, Auclair-Ronzaud J, Wimel L, Duranthon V, Chavatte-Palmer P. Maternal age affects equine day 8 embryo gene expression both in trophoblast and inner cell mass. BMC Genomics 2022 Jun 15;23(1):443.
        doi: 10.1186/s12864-022-08593-7pubmed: 35705916google scholar: lookup
      2. Niikura T, Tsogtgerel M, Niikura C, Wada H, Kanzawa S, Fujiwara T, Nambo Y. Effect of prostaglandin F2(α) administration on uterine polymorphonuclear neutrophil counts in Japanese heavy draft horses. J Equine Sci 2021 Dec;32(4):117-124.
        doi: 10.1294/jes.32.117pubmed: 35023989google scholar: lookup
      3. Benammar A, Derisoud E, Vialard F, Palmer E, Ayoubi JM, Poulain M, Chavatte-Palmer P. The Mare: A Pertinent Model for Human Assisted Reproductive Technologies?. Animals (Basel) 2021 Aug 4;11(8).
        doi: 10.3390/ani11082304pubmed: 34438761google scholar: lookup
      4. Catandi GD, Obeidat YM, Broeckling CD, Chen TW, Chicco AJ, Carnevale EM. Equine maternal aging affects oocyte lipid content, metabolic function and developmental potential. Reproduction 2021 Apr;161(4):399-409.
        doi: 10.1530/REP-20-0494pubmed: 33539317google scholar: lookup
      5. Dorado J, Bottrel M, Ortiz I, Díaz-Jiménez M, Pereira B, Consuegra C, Carrasco JJ, Gómez-Arrones V, Domingo A, Hidalgo M. Factors Affecting Embryo Recovery Rate, Quality, and Diameter in Andalusian Donkey Jennies. Animals (Basel) 2020 Oct 26;10(11).
        doi: 10.3390/ani10111967pubmed: 33114673google scholar: lookup
      6. Warriach HM, Memon MA, Ahmad N, Norman ST, Ghafar A, Arif M. Reproductive Performance of Arabian and Thoroughbred Mares under Subtropical Conditions of Pakistan. Asian-Australas J Anim Sci 2014 Jul;27(7):932-6.
        doi: 10.5713/ajas.2013.13547pubmed: 25050033google scholar: lookup
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