Reproductive performance of a cohort of Standardbred mares under a commercial breeding system.
Equine Vet J
; 2023 Aug 09.
Article
em En
| MEDLINE
| ID: mdl-37559421
ABSTRACT
BACKGROUND:
Despite being a large commercial breeding industry, there is little published data on the reproductive success of Standardbred mares.OBJECTIVES:
To quantify the reproductive performance of Standardbred mares under artificial breeding systems in a commercial setting and determine the incidence of early embryonic and other pre-partum losses. STUDYDESIGN:
Retrospective cohort study.METHODS:
Data from four commercial farms were collected across four breeding years, and all mares were bred via artificial insemination. A total of 3995 mares contributed 7229 mare years. First-cycle pregnancy rate (FCPR) and end of season pregnancy rate (SPR) were analysed in mixed-effects logistic regression models. Time-to-conception interval was analysed in a Cox regression model.RESULTS:
The mean FCPR was 61.4% (confidence interval [CI] 60.3%-62.6%), the mean end of SPR was 84.7% (CI 83.8-85.5%), the mean live foal rate (FR) was 73.1% (CI 72.1%-74.2%). Mares located on-farm were more probable to be pregnant in terms of both FCPR (odds ratio [OR] 1.168, CI 1.018-1.340, p = 0.026) and SPR (OR 2.026, CI 1.673-2.454, p < 0.001), mares inseminated with thawed-frozen semen were less probable to be pregnant in terms of FCPR (OR 0.598, CI 0.457-0.783, p < 0.001) and SPR (OR 0.479, CI 0.354-0.647, p < 0.001) compared with insemination with fresh-extended semen. Older mares (14 years and older) were less probable to be pregnant in terms of FCPR (OR 0.795, CI 0.688-0.919, p = 0.002) and SPR (0.435, CI 0.352-0.538, p < 0.001) compared with young mares (3- to 8-year old). MAINLIMITATIONS:
Retrospective data relied on accurate record keeping of stud farms and no mare-treatment or ovulation induction records were available. Live FRs relied mostly on annual foaling returns so fetal/foal deaths may be underrepresented.CONCLUSION:
This study provides substantial baseline data on reproductive performance for Standardbred mares managed under a commercial artificial breeding system.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Tipo de estudo:
Observational_studies
/
Risk_factors_studies
Idioma:
En
Revista:
Equine Vet J
Ano de publicação:
2023
Tipo de documento:
Article