{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,1]],"date-time":"2026-10-01T11:13:26Z","timestamp":1790853206876,"version":"4.1.0"},"reference-count":77,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2026,5,5]],"date-time":"2026-05-05T00:00:00Z","timestamp":1777939200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Animals"],"abstract":"<jats:p>The equine reproductive microbiota has emerged as an important factor influencing reproductive health and fertility in both mares and stallions. Traditionally, the equine uterus was considered sterile, and microbial presence was interpreted primarily in the context of infection. However, sequencing-based studies have demonstrated that the reproductive tract, including the uterus and semen, contains detectable microbial communities or microbial DNA signatures, challenging this traditional paradigm. In mares, the vaginal microbiota is consistently dominated by Firmicutes, Bacteroidetes, Proteobacteria, and Actinobacteria, whereas the uterine environment represents a low-biomass niche in which interpretation is complicated by contamination risk and the inability of sequencing-based methods to distinguish viable from nonviable microorganisms. Culture-based studies consistently identify opportunistic pathogens such as Streptococcus equi subsp. zooepidemicus, Escherichia coli, and Pseudomonas aeruginosa in association with endometritis and persistent breeding-induced endometritis, while sequencing-based studies suggest broader community-level dysbiosis rather than simple pathogen presence. In stallions, semen is not sterile and commonly contains taxa such as Porphyromonas, Corynebacterium, Peptoniphilus, and other opportunistic bacteria that may influence sperm quality and microbial transmission to mares during breeding. However, most reported associations remain correlative, and direct longitudinal evidence for persistent stallion-to-mare microbial transmission is limited. This review synthesizes current evidence on microbial composition, hormonal influences, dysbiosis, and reproductive implications of the equine reproductive microbiota, integrating culture-based and sequencing-based findings while emphasizing methodological limitations associated with low-biomass samples. Improved understanding of these microbial ecosystems may support more evidence-based reproductive diagnostics and microbiome-informed fertility management in horses.<\/jats:p>","DOI":"10.3390\/ani16091414","type":"journal-article","created":{"date-parts":[[2026,5,5]],"date-time":"2026-05-05T13:23:37Z","timestamp":1777987417000},"page":"1414","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["The Equine Reproductive Microbiota: Composition, Dynamics, Dysbiosis, and Implications for Fertility in Mares and Stallions"],"prefix":"10.3390","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0009-0007-4653-5608","authenticated-orcid":false,"given":"Urt\u0117","family":"Pelen\u0117","sequence":"first","affiliation":[{"name":"Department of Animal Breeding and Reproduction, Animal Science Institute, Lithuanian University of Health Sciences, R. Zebenkos 12, 82317 Baisogala, Lithuania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Art\u016bras","family":"\u0160iuk\u0161\u010dius","sequence":"additional","affiliation":[{"name":"Department of Animal Breeding and Reproduction, Animal Science Institute, Lithuanian University of Health Sciences, R. Zebenkos 12, 82317 Baisogala, Lithuania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1596-5249","authenticated-orcid":false,"given":"Rasa","family":"Nainien\u0117","sequence":"additional","affiliation":[{"name":"Department of Animal Breeding and Reproduction, Animal Science Institute, Lithuanian University of Health Sciences, R. Zebenkos 12, 82317 Baisogala, Lithuania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0007-7698-1510","authenticated-orcid":false,"given":"Inga","family":"Merkelyt\u0117","sequence":"additional","affiliation":[{"name":"Department of Animal Breeding and Reproduction, Animal Science Institute, Lithuanian University of Health Sciences, R. Zebenkos 12, 82317 Baisogala, Lithuania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"R\u016bta","family":"\u0160veistien\u0117","sequence":"additional","affiliation":[{"name":"Department of Animal Breeding and Reproduction, Animal Science Institute, Lithuanian University of Health Sciences, R. Zebenkos 12, 82317 Baisogala, Lithuania"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,5,5]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"311","DOI":"10.14202\/vetworld.2025.311-328","article-title":"Strategic Approaches to Improve Equine Breeding and Stud Farm Outcomes","volume":"18","author":"Khan","year":"2025","journal-title":"Vet. World"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"103016","DOI":"10.1016\/j.jevs.2020.103016","article-title":"Contribution of Reproduction Management and Technologies to Genetic Progress in Horse Breeding","volume":"89","author":"Palmer","year":"2020","journal-title":"J. Equine Vet. Sci."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"653","DOI":"10.21836\/PEM20030616","article-title":"Early Pregnancy Loss in Aged Mares: Probable Causes and Possible Cures","volume":"19","author":"Rambags","year":"2003","journal-title":"Pferdeheilkunde"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"263","DOI":"10.1016\/S0749-0739(17)30641-7","article-title":"Embryonic Loss in Mares: Incidence, Possible Causes, and Diagnostic Considerations","volume":"4","author":"Ball","year":"1988","journal-title":"Vet. Clin. North Am. Equine Pract."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"149","DOI":"10.1016\/S0749-0739(17)30472-8","article-title":"Evaluation of the Stallion for Breeding Soundness","volume":"8","author":"Hurtgen","year":"1992","journal-title":"Vet. Clin. North Am. Equine Pract."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"407","DOI":"10.1016\/j.jevs.2010.05.005","article-title":"Some Factors Associated With Fertility of Thoroughbred Stallions","volume":"30","author":"Blanchard","year":"2010","journal-title":"J. Equine Vet. Sci."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Schrimpf, R., Gottschalk, M., Metzger, J., Martinsson, G., Sieme, H., and Distl, O. (2016). Screening of Whole Genome Sequences Identified High-Impact Variants for Stallion Fertility. BMC Genom., 17.","DOI":"10.1186\/s12864-016-2608-3"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"776","DOI":"10.1111\/evj.13989","article-title":"Reproductive Performance of a Cohort of Standardbred Mares under a Commercial Breeding System","volume":"56","author":"Tanner","year":"2024","journal-title":"Equine Vet. J."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"711","DOI":"10.1111\/evj.14057","article-title":"Does Inbreeding Contribute to Pregnancy Loss in Thoroughbred Horses?","volume":"56","author":"Lawson","year":"2024","journal-title":"Equine Vet. J."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"301","DOI":"10.1530\/RAF-22-0087","article-title":"Multivariable Analysis to Determine Risk Factors Associated with Abortion in Mares","volume":"3","author":"Roach","year":"2022","journal-title":"Reprod. Fertil."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Wobbe, M., Reinhardt, F., Reents, R., Tetens, J., and Stock, K.F. (2022). Quantifying the Effect of Warmblood Fragile Foal Syndrome on Foaling Rates in the German Riding Horse Population. PLoS ONE, 17.","DOI":"10.1371\/journal.pone.0267975"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"R95","DOI":"10.1530\/REP-19-0478","article-title":"Equine Endometritis: A Review of Challenges and New Approaches","volume":"160","author":"Morris","year":"2020","journal-title":"Reproduction"},{"key":"ref_13","first-page":"343","article-title":"Role of Anaerobic Bacteria in Equine Endometritis","volume":"35","author":"Ricketts","year":"1987","journal-title":"J. Reprod. Fertil. Suppl."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"72","DOI":"10.2460\/javma.1988.193.01.72","article-title":"Clinical Significance of Aerobic Bacterial Flora of the Uterus, Vagina, Vestibule, and Clitoral Fossa of Clinically Normal Mares","volume":"193","author":"Hinrichs","year":"1988","journal-title":"J. Am. Vet. Med. Assoc."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Gil-Miranda, A., Macnicol, J., Orellana-Guerrero, D., Samper, J.C., and Gomez, D.E. (2024). Reproductive Tract Microbiota of Mares. Vet. Sci., 11.","DOI":"10.3390\/vetsci11070324"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"14790","DOI":"10.1038\/s41598-022-18971-6","article-title":"The Healthy Equine Uterus Harbors a Distinct Core Microbiome plus a Rich and Diverse Microbiome That Varies with Geographical Location","volume":"12","author":"Holyoak","year":"2022","journal-title":"Sci. Rep."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"797","DOI":"10.5455\/OVJ.2022.v12.i6.3","article-title":"Characterization of Microbial Communities and Predicted Metabolic Pathways in the Uterus of Healthy Mares","volume":"12","author":"Thomson","year":"2022","journal-title":"Open Vet. J."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"104724","DOI":"10.1016\/j.jevs.2023.104724","article-title":"Association of the uterine microbiome to mare fertility","volume":"125","author":"Krekeler","year":"2023","journal-title":"J. Equine Vet. Sci."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"103","DOI":"10.1186\/s40168-020-00875-0","article-title":"Microbiome Definition Re-Visited: Old Concepts and New Challenges","volume":"8","author":"Berg","year":"2020","journal-title":"Microbiome"},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Poole, R.K., Soffa, D.R., McAnally, B.E., Smith, M.S., Hickman-Brown, K.J., and Stockland, E.L. (2023). Reproductive Microbiomes in Domestic Livestock: Insights Utilizing 16S rRNA Gene Amplicon Community Sequencing. Animals, 13.","DOI":"10.3390\/ani13030485"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"24","DOI":"10.1186\/s13099-016-0103-7","article-title":"Inherent Bacterial DNA Contamination of Extraction and Sequencing Reagents May Affect Interpretation of Microbiota in Low Bacterial Biomass Samples","volume":"8","author":"Glassing","year":"2016","journal-title":"Gut Pathog."},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Salter, S.J., Cox, M.J., Turek, E.M., Calus, S.T., Cookson, W.O., Moffatt, M.F., Turner, P., Parkhill, J., Loman, N.J., and Walker, A.W. (2014). Reagent and Laboratory Contamination Can Critically Impact Sequence-Based Microbiome Analyses. BMC Biol., 12.","DOI":"10.1186\/s12915-014-0087-z"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"e00290-19","DOI":"10.1128\/mSystems.00290-19","article-title":"Controlling for Contaminants in Low-Biomass 16S rRNA Gene Sequencing Experiments","volume":"4","author":"Karstens","year":"2019","journal-title":"mSystems"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"226","DOI":"10.1186\/s40168-018-0605-2","article-title":"Simple Statistical Identification and Removal of Contaminant Sequences in Marker-Gene and Metagenomics Data","volume":"6","author":"Davis","year":"2018","journal-title":"Microbiome"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"1570","DOI":"10.1038\/s41564-025-02035-2","article-title":"Guidelines for Preventing and Reporting Contamination in Low-Biomass Microbiome Studies","volume":"10","author":"Fierer","year":"2025","journal-title":"Nat. Microbiol."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"97","DOI":"10.1002\/cjp2.151","article-title":"Microbiome Applications for Pathology: Challenges of Low Microbial Biomass Samples during Diagnostic Testing","volume":"6","author":"Selway","year":"2020","journal-title":"J. Pathol. Clin. Res."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Canisso, I.F., Segabinazzi, L.G.T.M., and Fedorka, C.E. (2020). Persistent Breeding-Induced Endometritis in Mares\u2014A Multifaceted Challenge: From Clinical Aspects to Immunopathogenesis and Pathobiology. Int. J. Mol. Sci., 21.","DOI":"10.3390\/ijms21041432"},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Katila, T., and Ferreira-Dias, G. (2022). Evolution of the Concepts of Endometrosis, Post Breeding Endometritis, and Susceptibility of Mares. Animals, 12.","DOI":"10.3390\/ani12060779"},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Guo, L., Holyoak, G.R., and DeSilva, U. (2025). Endometrial Microbiome in Mares with and without Clinical Endometritis. Front. Vet. Sci., 12.","DOI":"10.3389\/fvets.2025.1588432"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"1024","DOI":"10.1111\/cmi.12308","article-title":"Defining Dysbiosis and Its Influence on Host Immunity and Disease","volume":"16","author":"Petersen","year":"2014","journal-title":"Cell. Microbiol."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"1486","DOI":"10.1080\/10408398.2022.2117784","article-title":"The Effects of Microbiota on Reproductive Health: A Review","volume":"64","author":"Wang","year":"2022","journal-title":"Crit. Rev. Food Sci. Nutr."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"e20200052","DOI":"10.1590\/1984-3143-ar2020-0052","article-title":"Characterization of the Seminal Bacterial Microbiome of Healthy, Fertile Stallions Using next-Generation Sequencing","volume":"18","author":"Hidalgo","year":"2021","journal-title":"Anim. Reprod."},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Qui\u00f1ones-P\u00e9rez, C., Mart\u00ednez, A., Ortiz, I., Crespo, F., and Vega-Pla, J.L. (2022). The Semen Microbiome and Semen Parameters in Healthy Stallions. Animals, 12.","DOI":"10.3390\/ani12050534"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"1409","DOI":"10.1007\/s11259-024-10321-3","article-title":"Bacterial Diversity in Semen from Stallions in Three European Countries Evaluated by 16S Sequencing","volume":"48","author":"Malaluang","year":"2024","journal-title":"Vet. Res. Commun."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"RD23117","DOI":"10.1071\/RD23117","article-title":"The Semen Microbiome of Miniature Pony Stallions","volume":"36","author":"Cooke","year":"2024","journal-title":"Reprod. Fertil. Dev."},{"key":"ref_36","doi-asserted-by":"crossref","unstructured":"Qui\u00f1ones-P\u00e9rez, C., Mart\u00ednez, A., Crespo, F., and Vega-Pla, J.L. (2020). Comparative Semen Microbiota Composition of a Stallion in a Taylorella Equigenitalis Carrier and Non-Carrier State. Animals, 10.","DOI":"10.3390\/ani10050868"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"105354","DOI":"10.1016\/j.rvsc.2024.105354","article-title":"16s Gene Metagenomic Characterization in Healthy Stallion Semen","volume":"176","author":"Leal","year":"2024","journal-title":"Res. Vet. Sci."},{"key":"ref_38","unstructured":"Morel, M.C.G.D. (2008). Equine Reproductive Physiology, Breeding and Stud Management, CABI. [3rd ed.]."},{"key":"ref_39","doi-asserted-by":"crossref","unstructured":"Pinto, C.R.F. (2017). Reproductive Evaluation of the Mare. Manual of Clinical Procedures in the Horse, John Wiley & Sons, Ltd.","DOI":"10.1002\/9781118939956.ch36"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"10","DOI":"10.21836\/PEM20100102","article-title":"A Clinical View of Mare Reproductive Physiology","volume":"26","author":"Paccamonti","year":"2010","journal-title":"Pferdeheilkunde Equine Med."},{"key":"ref_41","doi-asserted-by":"crossref","unstructured":"McCue, P.M. (2014). Reproductive Evaluation of the Mare. Equine Reproductive Procedures, John Wiley & Sons, Ltd.","DOI":"10.1002\/9781118904398.ch1"},{"key":"ref_42","doi-asserted-by":"crossref","unstructured":"Satu\u00e9, K., and Gardon, J.C. (2016). Infection and Infertility in Mares. Genital Infections and Infertility, IntechOpen.","DOI":"10.5772\/63741"},{"key":"ref_43","doi-asserted-by":"crossref","unstructured":"Barba, M., Mart\u00ednez-Bov\u00ed, R., Quereda, J.J., Moc\u00e9, M.L., Plaza-D\u00e1vila, M., Jim\u00e9nez-Trigos, E., G\u00f3mez-Mart\u00edn, \u00c1., Gonz\u00e1lez-Torres, P., Carbonetto, B., and Garc\u00eda-Rosell\u00f3, E. (2020). Vaginal Microbiota Is Stable throughout the Estrous Cycle in Arabian Mares. Animals, 10.","DOI":"10.3390\/ani10112020"},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"11","DOI":"10.1016\/j.theriogenology.2023.09.011","article-title":"Bacteria in the Healthy Equine Vagina during the Estrous Cycle","volume":"213","author":"Malaluang","year":"2024","journal-title":"Theriogenology"},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"105134","DOI":"10.1016\/j.jevs.2024.105134","article-title":"Metagenomic Characterization of the Equine Endometrial Microbiome during Anestrus","volume":"140","author":"Heil","year":"2024","journal-title":"J. Equine Vet. Sci."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"55","DOI":"10.1016\/0093-691X(88)90031-3","article-title":"Use of Ultrasonography in Reproductive Management of Mares","volume":"29","author":"Squires","year":"1988","journal-title":"Theriogenology"},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"220","DOI":"10.1016\/j.anireprosci.2011.02.005","article-title":"Reproductive Cycles of Horses","volume":"124","author":"Aurich","year":"2011","journal-title":"Anim. Reprod. Sci."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"43","DOI":"10.1262\/jrd.10-023T","article-title":"Relationships Between Uterine Blood Flow, Peripheral Sex Steroids, Expression of Endometrial Estrogen Receptors and Nitric Oxide Synthases During the Estrous Cycle in Mares","volume":"57","author":"Honnens","year":"2011","journal-title":"J. Reprod. Dev."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"575","DOI":"10.1016\/0093-691X(92)90020-R","article-title":"Progesterone and Estrogen Receptor Distribution in the Endometrium of the Mare","volume":"38","author":"Watson","year":"1992","journal-title":"Theriogenology"},{"key":"ref_50","doi-asserted-by":"crossref","unstructured":"Malaluang, P., Wil\u00e9n, E., Frosth, S., Lindahl, J., Hansson, I., and Morrell, J.M. (2022). Vaginal Bacteria in Mares and the Occurrence of Antimicrobial Resistance. Microorganisms, 10.","DOI":"10.3390\/microorganisms10112204"},{"key":"ref_51","first-page":"657","article-title":"A Comparison of Microbiological and Molecular Detection of Vaginal Lactobacillus Spp. between Mares and Women","volume":"10","author":"Borges","year":"2013","journal-title":"Anim. Reprod."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"71","DOI":"10.1007\/s10482-007-9180-4","article-title":"Vaginal Lactic Acid Bacteria in the Mare: Evaluation of the Probiotic Potential of Native Lactobacillus Spp. and Enterococcus Spp. Strains","volume":"93","author":"Fraga","year":"2008","journal-title":"Antonie Leeuwenhoek"},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"5270993","DOI":"10.1155\/vmi\/5270993","article-title":"The Uterine Microbiota in Mares With Endometritis: Impacts of Antibiotic Treatment","volume":"2026","author":"Donato","year":"2026","journal-title":"Vet. Med. Int."},{"key":"ref_54","doi-asserted-by":"crossref","unstructured":"Donato, G.G., Necchi, D., Gionechetti, F., Ala, U., Nebbia, P., Robino, P., Stella, M.C., Vandaele, H., Pallavicini, A., and Nervo, T. (2026). Characterization of the Endometrial Microbiota of Healthy Mares Across the Estrous Cycle. Animals, 16.","DOI":"10.3390\/ani16040618"},{"key":"ref_55","doi-asserted-by":"crossref","unstructured":"Tyrnenopoulou, P., and Fthenakis, G.C. (2023). Clinical Aspects of Bacterial Distribution and Antibiotic Resistance in the Reproductive System of Equids. Antibiotics, 12.","DOI":"10.3390\/antibiotics12040664"},{"key":"ref_56","doi-asserted-by":"crossref","unstructured":"Morrell, J.M., and Rocha, A. (2022). A Novel Approach to Minimising Acute Equine Endometritis That May Help to Prevent the Development of the Chronic State. Front. Vet. Sci., 8.","DOI":"10.3389\/fvets.2021.799619"},{"key":"ref_57","doi-asserted-by":"crossref","first-page":"31","DOI":"10.1186\/s40168-015-0094-5","article-title":"The Vocabulary of Microbiome Research: A Proposal","volume":"3","author":"Marchesi","year":"2015","journal-title":"Microbiome"},{"key":"ref_58","doi-asserted-by":"crossref","unstructured":"Beckers, K.F., Liu, C.-C., Gomes, V.C.L., Schulz, C.J., Childers, G.W., Fedorka, C.E., and Sones, J.L. (2025). Effects of Intra-Uterine Ceftiofur on the Equine Uterine Microbiome. Vet. Sci., 12.","DOI":"10.3390\/vetsci12090837"},{"key":"ref_59","doi-asserted-by":"crossref","unstructured":"Malaluang, P., Wil\u00e9n, E., Frosth, S., Lindahl, J.F., Hansson, I., and Morrell, J.M. (2023). Antimicrobial Resistance in Vaginal Bacteria in Inseminated Mares. Pathogens, 12.","DOI":"10.3390\/pathogens12030375"},{"key":"ref_60","doi-asserted-by":"crossref","first-page":"83","DOI":"10.1016\/S0737-0806(81)80022-6","article-title":"A Review of Anatomy and Physiology of the Stallion","volume":"1","author":"Amann","year":"1981","journal-title":"J. Equine Vet. Sci."},{"key":"ref_61","unstructured":"Samper, J.C. (2008). Equine Breeding Management and Artificial Insemination, Elsevier Health Sciences."},{"key":"ref_62","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1186\/BF03547698","article-title":"Bacterial Flora of Semen Collected from Danish Warmblood Stallions by Artificial Vagina","volume":"36","author":"Maasen","year":"1995","journal-title":"Acta Vet. Scand."},{"key":"ref_63","doi-asserted-by":"crossref","first-page":"53","DOI":"10.1016\/j.anireprosci.2013.03.009","article-title":"Development of the Genital Microflora in Stallions Used for Artificial Insemination throughout the Breeding Season","volume":"139","author":"Pasing","year":"2013","journal-title":"Anim. Reprod. Sci."},{"key":"ref_64","doi-asserted-by":"crossref","first-page":"25","DOI":"10.1186\/s13028-019-0459-z","article-title":"Bacteria Detected in the Genital Tract, Semen or Pre-Ejaculatory Fluid of Swedish Stallions from 2007 to 2017","volume":"61","author":"Eriksson","year":"2019","journal-title":"Acta Vet. Scand."},{"key":"ref_65","doi-asserted-by":"crossref","first-page":"100143","DOI":"10.1016\/j.vas.2020.100143","article-title":"Microbiota of Semen from Stallions in Sweden Identified by MALDI-TOF","volume":"10","author":"Eriksson","year":"2020","journal-title":"Vet. Anim. Sci."},{"key":"ref_66","doi-asserted-by":"crossref","first-page":"106568","DOI":"10.1016\/j.anireprosci.2020.106568","article-title":"Metagenomic Analysis of Bacteria in Stallion Semen","volume":"221","author":"Guo","year":"2020","journal-title":"Anim. Reprod. Sci."},{"key":"ref_67","doi-asserted-by":"crossref","first-page":"26","DOI":"10.1186\/1297-9716-44-26","article-title":"Streptococcus Equi Subsp. Zooepidemicus Isolates from Equine Infectious Endometritis Belong to a Distinct Genetic Group","volume":"44","author":"Rasmussen","year":"2013","journal-title":"Vet. Res."},{"key":"ref_68","doi-asserted-by":"crossref","unstructured":"Wilson, M., Williams, J., Montrose, V.T., and Williams, J. (2019). Variance in Stallion Semen Quality among Equestrian Sporting Disciplines and Competition Levels. Animals, 9.","DOI":"10.3390\/ani9080485"},{"key":"ref_69","doi-asserted-by":"crossref","unstructured":"Jlassi, M., Jemmali, B., Ouzari, H.I., Lasfer, F., Aoun, B.B., and Ben Gara, A. (2023). Reproductive Performance of Tunisian Arabian Stallions: A Study on the Variance and Estimation of Heritability. Animals, 13.","DOI":"10.3390\/ani13060991"},{"key":"ref_70","first-page":"1","article-title":"Current Trends on Stallion Semen Evaluation: What Other Methods Can Be Used to Improve Our Capacity for Semen Quality Assessment?","volume":"4","year":"2019","journal-title":"J. Vet. Androl."},{"key":"ref_71","doi-asserted-by":"crossref","unstructured":"Egyptien, S., Deleuze, S., Ledeck, J., and Ponthier, J. (2023). Sperm Quality Assessment in Stallions: How to Choose Relevant Assays to Answer Clinical Questions. Animals, 13.","DOI":"10.3390\/ani13193123"},{"key":"ref_72","doi-asserted-by":"crossref","unstructured":"Khan, I.M., Nassar, N., Chang, H., Khan, S., Cheng, M., Wang, Z., and Xiang, X. (2024). The Microbiota: A Key Regulator of Health, Productivity, and Reproductive Success in Mammals. Front. Microbiol., 15.","DOI":"10.3389\/fmicb.2024.1480811"},{"key":"ref_73","doi-asserted-by":"crossref","first-page":"11","DOI":"10.1186\/s43043-023-00136-8","article-title":"Reproductive Tract Microbiome and Therapeutics of Infertility","volume":"28","author":"Bhattacharya","year":"2023","journal-title":"Middle East Fertil. Soc. J."},{"key":"ref_74","doi-asserted-by":"crossref","first-page":"607","DOI":"10.1039\/D3MO00089C","article-title":"Integrated Multi-Omics Analyses of Microbial Communities: A Review of the Current State and Future Directions","volume":"19","author":"Muth","year":"2023","journal-title":"Mol. Omics"},{"key":"ref_75","doi-asserted-by":"crossref","first-page":"bbaf323","DOI":"10.1093\/bib\/bbaf323","article-title":"Integrative Systems Biology Approaches for Analyzing Microbiome Dysbiosis and Species Interactions","volume":"26","author":"Nasar","year":"2025","journal-title":"Brief. Bioinform."},{"key":"ref_76","doi-asserted-by":"crossref","first-page":"618","DOI":"10.1021\/envhealth.4c00094","article-title":"Antibiotics Misuse and Antimicrobial Resistance Development in Agriculture: A Global Challenge","volume":"2","author":"Singh","year":"2024","journal-title":"Environ. Health"},{"key":"ref_77","doi-asserted-by":"crossref","unstructured":"Zabala, S.M., Serres, C., Montero, N., Crespo, F., Lorenzo, P.L., P\u00e9rez-Aguilera, V., Oliet, A., Hij\u00f3n, V., Moreno, S., and Gonz\u00e1lez-Zorn, B. (2025). Innovative Approaches to Avoid Antibiotic Use in Equine Semen Cryopreservation: Advancing Sustainable Reproductive Technologies. 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