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Animals : an open access journal from MDPI2022; 12(14); 1841; doi: 10.3390/ani12141841

Mixed-Effects Modelling of the Risk Factors Associated with Multiple Pregnancies in Thoroughbred Mares.

Abstract: Multiple pregnancies (MPs) are commonly diagnosed during breeding management of mares. Whilst some studies have reported on factors associated with the risk of MPs, few have utilised multivariable data analysis to control for confounding variables. A prospective cohort study of Thoroughbred broodmares was conducted with information collected on 27 factors. Mixed-effects logistic regression was used to determine risk factors for MPs. Mare, stallion, stud, and veterinarian were evaluated as random effects. The prevalence of MPs in 1754 mares and 2245 pregnancies was 16.06% (95% confidence interval [CI] = 14.54, 17.58). Multiple ovulations (OR = 15.57, 95% CI = 11.88, 20.53) and treatment with cloprostenol (OR = 1.35, 95% CI = 1.015, 1.80) were associated with increased odds of MPs following multivariable analysis. Mares that foaled at the start of the breeding season (OR = 0.66, 95% CI = 0.47, 0.94), conceived at the second or more oestrus cycles (OR = 0.60, 95% CI= 0.43, 0.84), or identified with a uterine cyst (OR = 0.63, 95% CI = 0.40, 0.97) were at reduced odds of conceiving MPs. Mare, stallion, stud, and veterinarian were not associated with MPs. These findings provide possible explanations as to why the prevalence of MPs but not MOs have increased over the last decade.
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Publication Date: 2022-07-20 PubMed ID: 35883388PubMed Central: PMC9312083DOI: 10.3390/ani12141841Google 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 investigated the main risk factors associated with multiple pregnancies in Thoroughbred mares, using a complex data analysis model to account for varied variables. It found that multiple ovulations and treatment with cloprostenol increase the odds of multiple pregnancies, while mares that foaled at the start of the breeding season, conceived at the second or subsequent oestrus cycles, or had a uterine cyst had less likelihood of conceiving multiple pregnancies.

Objective and Methodology of the Study

  • The research conducted a prospective cohort study focused on Thoroughbred broodmares.
  • Data about 27 different factors was collected for analysis.
  • A method of data analysis referred to as mixed-effects logistic regression was employed. This method helps in identifying and measuring the impact of different risk factors while controlling for confounding variables.
  • The prevalence of multiple pregnancies was established to be about 16.06% in the 1754 mares and 2245 pregnancies included in the study.

Key Findings of the Study

  • Two primary factors were associated with increased odds for multiple pregnancies in mares: multiple ovulations and treatment using a drug known as cloprostenol.
  • On the other hand, certain factors were found to reduce the likelihood of multiple pregnancies in mares. These include: foaling at the start of the breeding season, conceiving during the second or any subsequent oestrus cycles, and having a uterine cyst.
  • In their capacity as random effects, the specific mare, stallion, stud, and veterinarian involved in the breeding process were not found to have a significant association with multiple pregnancies.

Significance of the Study

  • The study presents possible explanations as to why the prevalence of multiple pregnancies but not multiple ovulations has risen in the last decade. This could suggest that other factors, aside from multiple ovulations, are influencing this trend.
  • By understanding the risk factors for multiple pregnancies in mares, breeders and veterinarians may be better equipped to manage breeding to achieve desired outcomes, improve mare health, and reduce potential complications.

Cite This Article

APA
Salem SE, Sinnott A, Roach JM, Verheyen KLP, de Mestre AM. (2022). Mixed-Effects Modelling of the Risk Factors Associated with Multiple Pregnancies in Thoroughbred Mares. Animals (Basel), 12(14), 1841. https://doi.org/10.3390/ani12141841

Publication

Animals : an open access journal from MDPI
ISSN: 2076-2615
NlmUniqueID: 101635614
Country: Switzerland
Language: English
Volume: 12
Issue: 14
PII: 1841

Researcher Affiliations

Salem, Shebl E
  • Department of Pathobiology and Population Sciences, The Royal Veterinary College, Hawkshead Lane, Hertfordshire AL9 7TA, UK.
Sinnott, Alannah
  • Department of Comparative Biomedical Sciences, The Royal Veterinary College, Hawkshead Lane, Hertfordshire AL9 7TA, UK.
Roach, Jessica M
  • Department of Comparative Biomedical Sciences, The Royal Veterinary College, Hawkshead Lane, Hertfordshire AL9 7TA, UK.
Verheyen, Kristien L P
  • Department of Pathobiology and Population Sciences, The Royal Veterinary College, Hawkshead Lane, Hertfordshire AL9 7TA, UK.
de Mestre, Amanda M
  • Department of Comparative Biomedical Sciences, The Royal Veterinary College, Hawkshead Lane, Hertfordshire AL9 7TA, UK.

Grant Funding

  • TBA250 / Horserace Betting Levy Board

Conflict of Interest Statement

The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.

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Citations

This article has been cited 1 times.
  1. Khan IU, Khairullah AR, Khan AY, Rehman AU, Mustofa I. Strategic approaches to improve equine breeding and stud farm outcomes. Vet World 2025 Feb;18(2):311-328.
    doi: 10.14202/vetworld.2025.311-328pubmed: 40182817google scholar: lookup
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