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Home / Equine Research Bank / Reprod Fertil / Multivariable analysis to determine risk factors associated ...
Reproduction & fertility2022; 3(4); 301-312; doi: 10.1530/RAF-22-0087

Multivariable analysis to determine risk factors associated with abortion in mares.

Abstract: Risk factors associated with equine reproductive efficiency have been identified along with those associated specifically with early pregnancy loss (EPL). In contrast, no studies have reported risk factors associated with abortion (loss between day 70 and 300 post-cover). Given the causes of abortion differ to those of EPL, likely too will the risk factors. A retrospective cohort study was carried out to identify risk factors associated with abortion in UK and Irish based Thoroughbreds, collecting data on 20 exposure variables over a five-year period. A generalized linear mixed model was utilized to evaluate the associations between exposure variables and abortion, with clustering of observations accounted for at the mare and farm level. Variables with a likelihood ratio test (LRT) p value <0.2 were entered into the model in a forward stepwise approach. Pregnancy outcome was available on 4,439 pregnancies from 2,510 mares. Having had two or more prior abortions (odds ratio (OR) 7.91, 95% confidence interval (CI) 2.86, 21.88), conceiving on the second or subsequent covered estrous cycle (OR 1.84, 95% CI 1.22, 2.78) and conceiving multiple conceptuses (OR 1.68, 95% CI 1.02, 2.76) were associated with an increased risk of abortion compared to null parous, first estrous cycle covers and singleton conceptions respectively. Increasing paternal age (OR 0.95, 95% CI 0.90, 0.99) was associated with a decreasing risk of abortion. Mare and farm variance were not significant in the final model, LRT p=0.43. These findings provide evidence-based data to inform Thoroughbred breeding management practices to help mitigate abortion risk.
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Publication Date: 2022-11-01 PubMed ID: 36374277PubMed Central: PMC9782406DOI: 10.1530/RAF-22-0087Google 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.

The research article investigates the risk factors associated with abortion in thoroughbred horses in the UK and Ireland. Using a detailed retrospective study spanning five years, the authors identified several factors that increase the occurrence of abortion, including multiple prior abortions and multiple conceptions.

Introduction and Methodology

  • The paper aims to fill the gap in existing literature by identifying and understanding the risk factors associated with abortion in thoroughbreds, defined as loss between days 70 to 300 post-cover. This is different from the previously studied early pregnancy loss (EPL).
  • The data collection was made on 20 exposure variables over a span of five years, using a retrospective cohort study approach. This suggests that the researchers gathered historical data on the mares under study and analyzed patterns and significant factors leading to abortion.
  • The researchers employed a generalized linear mixed model to study the connections between the risk (exposure) factors and abortion cases. This type of model allows for both fixed and random effects, which lets the researchers consider the potential impact of unmeasured or unknown factors. They also factored in the possibility of different observations being correlated at the mare and farm level.

Results

  • Findings were derived from analyzing the outcomes of 4,439 pregnancies from 2,510 mares. The variables that increased the abortion risk were two or more previous abortions, conceiving during the second or subsequent estrous cycle, and multiple conceptions.
  • Interestingly, increasing paternal age was observed to be associated with a decreasing risk of abortion. This contradicts the usual expectation that age increases health risks, and suggests a direction for future research.
  • The variance due to mare and farm were not significantly impacting in the final model outcome. This suggests that the individual characteristics of the mares or farm conditions did not significantly affect the risk of abortion when considering all of the factors in the model.

Impact

  • The findings of this study provide evidence-based data that can be used to improve thoroughbred breeding management practices. By understanding the risk factors, measures can be taken to avoid situations that increase abortion risk and therefore improve reproductive efficiency.

Cite This Article

APA
Roach J, Arango Sabogal JC, Smith K, Foote A, Verheyen K, de Mestre AM. (2022). Multivariable analysis to determine risk factors associated with abortion in mares. Reprod Fertil, 3(4), 301-312. https://doi.org/10.1530/RAF-22-0087

Publication

Reproduction & fertility
ISSN: 2633-8386
NlmUniqueID: 101778727
Country: England
Language: English
Volume: 3
Issue: 4
Pages: 301-312
PII: RAF-22-0087

Researcher Affiliations

Roach, Jessica
  • J Roach, Comparative Biomedical Sciences, Royal Veterinary College, Hatfield, United Kingdom of Great Britain and Northern Ireland.
Arango Sabogal, Juan Carlos
  • J Arango Sabogal, Pathobiology and Population Sciences, Royal Veterinary College, Hatfield, United Kingdom of Great Britain and Northern Ireland.
Smith, Ken
  • K Smith, Pathobiology and Population Sciences, Royal Veterinary College, Hatfield, United Kingdom of Great Britain and Northern Ireland.
Foote, Alastair
  • A Foote, Rossdales Laboratories, Newmarket, United Kingdom of Great Britain and Northern Ireland.
Verheyen, Kristien
  • K Verheyen, Pathobiology and Population Sciences, Royal Veterinary College, Hatfield, United Kingdom of Great Britain and Northern Ireland.
de Mestre, Amanda M
  • A de Mestre, Comparative Biomedical Sciences, Royal Veterinary College, Hatfield, United Kingdom of Great Britain and Northern Ireland.

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