A predictive model for reproductive performance following abortion in Thoroughbred mares.
Abstract: Pregnancy losses include early embryonic death (EED) and later (postimplantation) abortion. Abortions, particularly Equid herpesvirus (EHV-1) abortion epizootics, cause severe economic and production losses. The long-term effects of EHV-1 and other abortions on subsequent reproductive performance in broodmare populations, however, remain undefined. This study described the relationships of EED and abortion with the following reproductive outcomes in Thoroughbred systems: breeding efficiency, month of last breeding, subsequent pregnancy and live foal rates. A prospective cohort study in broodmare populations following EHV-1 epizootics on two South African farms was used to develop predictive models of the relative influences and interactions of reproductive variables associated with EHV-1 and other abortion causes on reproductive performance. EED predicted all the reproductive outcomes. Abortion predicted increased effort and month of breeding to establish pregnancy, but not becoming pregnant or foaling. Increasing age predicted decreased reproductive efficiency, and pregnancy and foaling probabilities. Mare reproductive status predicted breeding efficiency and the last month of breeding, but not establishing pregnancy. The last month of breeding predicted efficiency, pregnancy and foaling. Interestingly, breeding in the first month of the season was associated with an improved probability of pregnancy among barren mares.
Publication Date: 2012-10-31 PubMed ID: 23118044DOI: 10.1136/vr.100670Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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This study examines the long-term effects of Equid herpesvirus (EHV-1) and other causes of abortion on the reproductive performance in Thoroughbred mares. The researchers used a cohort study on South African farms to develop predictive models of the relative influences and interactions of various reproductive variables on reproductive performance and outcomes such as breeding efficiency, month of last breeding, subsequent pregnancy and live foal rates.
Research Objectives
- The research team aimed to understand the long-term impacts of abortions, especially those caused by EHV-1, on the future reproductive performance of Thoroughbred mares.
- They intended to explore the relationships of early embryonic death (EED) and abortion with various reproductive outcomes in Thoroughbred systems.
- They also wanted to develop predictive models demonstrating the relative influences and interactions of various reproductive variables associated with EHV-1 and other abortion causes on reproductive performance.
Research Methods
- The research involved a prospective cohort study conducted on broodmare populations of two South African farms that experienced EHV-1 epizootics.
- Data from the study were utilized to form predictive models for understanding the reproductive outcomes post-abortion.
Key Findings
- EED was found to be a predictor of all the investigated reproductive outcomes.
- Although abortion predicted an increased effort and month of breeding to establish pregnancy, it wasn’t linked directly with becoming pregnant or foaling.
- In line with existing knowledge, increasing age in mares was linked to decreased reproductive efficiency and lower likelihood of pregnancy and foaling.
- The reproductive status of a mare influenced its breeding efficiency and the last month of breeding, but not in establishing pregnancy.
- The last month of breeding was positively correlated with efficiency, pregnancy, and foaling.
- An interesting observation was that breeding in the first month of the season improved the likelihood of pregnancy among barren mares.
Implication of Findings
- The research expands our understanding of how abortion, especially due to EHV-1, impacts a mare’s future reproduction performance.
- The predictive models developed here can aid in management decisions related to horse breeding, contributing to better economic and production outcomes.
Cite This Article
APA
Schulman ML, Kass PH, Becker A, Van der Merwe B.
(2012).
A predictive model for reproductive performance following abortion in Thoroughbred mares.
Vet Rec, 172(2), 44.
https://doi.org/10.1136/vr.100670 Publication
Researcher Affiliations
- Section of Reproduction, University of Pretoria, Onderstepoort 0110, South Africa. martin.schulman@up.ac.za
MeSH Terms
- Abortion, Veterinary / epidemiology
- Abortion, Veterinary / virology
- Age Factors
- Animals
- Breeding
- Cohort Studies
- Female
- Herpesviridae Infections / complications
- Herpesviridae Infections / veterinary
- Herpesvirus 1, Equid
- Horse Diseases / virology
- Horses / physiology
- Models, Biological
- Predictive Value of Tests
- Pregnancy
- Pregnancy Complications, Infectious / veterinary
- Pregnancy Complications, Infectious / virology
- Pregnancy Outcome
- Pregnancy Rate
- Pregnancy, Animal / physiology
- Prospective Studies
- Reproduction / physiology
- South Africa
- Time Factors
Citations
This article has been cited 2 times.- Brown LJ, Brown G, Kydd J, Stout TAE, Schulman ML. Failure to detect equid herpesvirus types 1 and 4 DNA in placentae and healthy new-born Thoroughbred foals. J S Afr Vet Assoc 2019 May 30;90(0):e1-e5.
- Scholtz M, Guthrie AJ, Newton R, Schulman ML. Review of Pseudomonas aeruginosa and Klebsiella pneumoniae as venereal pathogens in horses. Equine Vet J 2025 May;57(3):587-597.
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