De Witt, Anika A.Fosgate, Geoffrey TheodoreSchulman, M.L. (Martin)2023-03-302023-05De Witt, A.A., Fosgate, G.T. & Schulman, M.L. (2023) The association between the endometrial biopsy grade and selected epidemiological and reproductive variables in a population of subfertile mares. Equine Veterinary Education, 35, e421–e428. Available from: https://doi.org/10.1111/eve.13722.0957-7734 (print)2042-3292 (online)10.1111/eve.13722http://hdl.handle.net/2263/90271APPENDIX 1: Biopsy report of mare 1 from an Arabian farm in Saudi Arabia submitted in 2009 and categorised as biopsy Grade I.APPENDIX 2: Biopsy report of mare 14 submitted from a South African Thoroughbred farm in 2013 and categorized as biopsy Grade IIA.APPENDIX 3: Biopsy report of mare 3 submitted from a Saudi Arabian Thoroughbred farm in 2014 and categorized as biopsy Grade IIBAPPENDIX 4: Biopsy report of mare 4 submitted by a South African referral veterinarian in 2002 and categorized as biopsy Grade IIB.APPENDIX 5: Biopsy report of mare 12 submitted from a South African American Saddlebred horse farm in 2012 and categorized as biopsy Grade III.BACKGROUND : Endometrosis, a multifactorial disease, is an important cause of subfertility in the mare, and its management is reliant on histological classification. OBJECTIVES : This study aimed to determine the association between increased endometrial biopsy grade with first a mare's breed specifically either Thoroughbred or non-Thoroughbred, age and barren status and second, a clinical history indicating one or more of acute endometritis, positive bacterial culture, previous dystocia and uterine fluid retention. STUDY DESIGN : Retrospective case series. METHODS : This retrospective study used historical reproductive data (2000–2015) from a population of 41 subfertile mares of various breeds, but mostly Thoroughbreds (30/41; 73%). Biopsies were interpreted by a single, experienced evaluator using the Kenney–Doig classification (1986). RESULTS : Endometrial biopsy grade was positively correlated with age (ρ = 0.606; p = 0.001) but not associated with other evaluated variables (p > 0.05). MAIN LIMITATIONS : Use of a small, non-randomly selected subfertile mare population. CONCLUSIONS : Mare age was an important predictor of her reproductive performance, and performing an endometrial biopsy is therefore indicated in older mares.en© 2022 EVJ Ltd. This is the pre-peer reviewed version of the following article : The association between the endometrial biopsy grade and selected epidemiological and reproductive variables in a population of subfertile mares. Equine Veterinary Education, 35, e421–e428. Available from: https://doi.org/10.1111/eve.13722. The definite version is available at : http://www.wileyonlinelibrary.com/journal/eve.BiopsyEndometrosisHorse (Equus caballus)MareReproductive performancePostprint Article