{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,15]],"date-time":"2026-09-15T10:22:43Z","timestamp":1789467763016,"version":"build-2803163510"},"reference-count":98,"publisher":"MDPI AG","issue":"18","license":[{"start":{"date-parts":[[2026,9,15]],"date-time":"2026-09-15T00:00:00Z","timestamp":1789430400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"earmarked fund","award":["CARS-42"],"award-info":[{"award-number":["CARS-42"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Animals"],"abstract":"<jats:p>Accurate and efficient early pregnancy diagnosis (EPD) in livestock is crucial for optimizing breeding management and enhancing productivity in modern animal husbandry. Over the past century, EPD technology has evolved from empirical methods to sophisticated techniques, encompassing biochemical marker detection, ultrasonic imaging, and further extending to emerging non-invasive approaches such as infrared thermography (IRT) and spectroscopic analysis. These advancements have not only improved diagnostic accuracy but also broadened the research scope to include small livestock and multiple species. This review critically examines the historical evolution, current methodologies, and applications of EPD technology, with a focus on analyzing the advantages and limitations of both traditional and emerging techniques. Additionally, it explores the potential of multimodal fusion strategies and artificial intelligence (AI) in EPD. At present, machine vision, wearable monitoring, and several AI applications remain prospective approaches rather than validated tools for routine EPD. The conclusion highlights that, despite significant progress, current technologies still face limitations in achieving in situ, non-contact, and high-throughput detection. Looking ahead, the integration of cutting-edge technologies, such as AI, small wearable sensors, and physiological time-series data analysis, holds promise for overcoming these bottlenecks, enabling more intelligent and efficient pregnancy diagnosis, and providing scientific support for modern animal husbandry.<\/jats:p>","DOI":"10.3390\/ani16182897","type":"journal-article","created":{"date-parts":[[2026,9,15]],"date-time":"2026-09-15T08:16:48Z","timestamp":1789460208000},"page":"2897","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["A Narrative Review of Early Pregnancy Diagnosis Technologies for Livestock: From Conventional to Intelligent Systems"],"prefix":"10.3390","volume":"16","author":[{"given":"Yang","family":"Shen","sequence":"first","affiliation":[{"name":"College of Engineering, China Agricultural University, Beijing 100083, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yujie","family":"Zhang","sequence":"additional","affiliation":[{"name":"College of Engineering, China Agricultural University, Beijing 100083, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0002-2818-1643","authenticated-orcid":false,"given":"Junyi","family":"Meng","sequence":"additional","affiliation":[{"name":"College of Engineering, China Agricultural University, Beijing 100083, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yutong","family":"Han","sequence":"additional","affiliation":[{"name":"College of Engineering, China Agricultural University, Beijing 100083, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0001-0451-1129","authenticated-orcid":false,"given":"Jitong","family":"Xu","sequence":"additional","affiliation":[{"name":"College of Engineering, China Agricultural University, Beijing 100083, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hongying","family":"Wang","sequence":"additional","affiliation":[{"name":"College of Engineering, China Agricultural University, Beijing 100083, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6936-6145","authenticated-orcid":false,"given":"Liangju","family":"Wang","sequence":"additional","affiliation":[{"name":"College of Engineering, China Agricultural University, Beijing 100083, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,9,15]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"15","DOI":"10.1016\/j.theriogenology.2024.08.014","article-title":"Identification of Nonpregnant Beef Cows Based on CL Size vs. Luteal Blood Perfusion at 21 Days after Timed Artificial Insemination","volume":"230","author":"Andrade","year":"2024","journal-title":"Theriogenology"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"200","DOI":"10.21451\/1984-3143-AR878","article-title":"Markers of Pregnancy: How Early Can We Detect Pregnancies in Cattle Using pregnancy-Associated Glycoproteins (PAGs) and microRNAs?","volume":"13","author":"Reese","year":"2016","journal-title":"Anim. Reprod."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Riaz, U., Idris, M., Ahmed, M., Ali, F., Farooq, U., and Yang, L. (2024). The Potential of Infrared Thermography for Early Pregnancy Diagnosis in Nili-Ravi Buffaloes. Animals, 14.","DOI":"10.3390\/ani14131966"},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Szel\u00e9nyi, Z., Szenci, O., Kov\u00e1cs, L., and Garcia-Ispierto, I. (2021). Practical Aspects of Twin Pregnancy Diagnosis in Cattle. Animals, 11.","DOI":"10.3390\/ani11041061"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"769","DOI":"10.24425\/pjvs.2019.131409","article-title":"Accuracy of Bovine Pregnancy-Associated Glycoproteins (bPAGs) in the Diagnosis of Pregnancy: A Comparative Study of Three Pregnancy Diagnostic Methods","volume":"22","author":"Ghaidan","year":"2019","journal-title":"Pol. J. Vet. Sci."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"239","DOI":"10.1016\/j.theriogenology.2016.04.037","article-title":"Pivotal Periods for Pregnancy Loss during the First Trimester of Gestation in Lactating Dairy Cows","volume":"86","author":"Wiltbank","year":"2016","journal-title":"Theriogenology"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"F33","DOI":"10.1530\/REP-17-0432","article-title":"Interferon-Tau and Fertility in Ruminants","volume":"154","author":"Forde","year":"2017","journal-title":"Reproduction"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"9915814","DOI":"10.1155\/2021\/9915814","article-title":"The Importance of Interferon-Tau in the Diagnosis of Pregnancy","volume":"2021","author":"Kowalczyk","year":"2021","journal-title":"BioMed Res. Int."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"211","DOI":"10.1146\/annurev-animal-021022-032214","article-title":"Pregnancy Establishment and Diagnosis in Livestock","volume":"13","author":"Ott","year":"2025","journal-title":"Annu. Rev. Anim. Biosci."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Li, Z., Gao, W., Shi, H., Xu, S., Zeng, Z., Wang, F., Lai, C., and Zhang, S. (2024). Evaluating the Net Energy Requirements for Maintenance Based on Indirect Calorimetry and Heart Rate Monitoring in Gestating Sows. Animals, 14.","DOI":"10.3390\/ani14192907"},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Sguizzato, A.L.L., Marcondes, M.I., Dijkstra, J., Valadares Filho, S.D.C., Campos, M.M., Machado, F.S., Silva, B.C., and Rotta, P.P. (2020). Energy Requirements for Pregnant Dairy Cows. PLoS ONE, 15.","DOI":"10.1371\/journal.pone.0235619"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"465","DOI":"10.3390\/dairy3030034","article-title":"Performing Early Pregnancy Tests in Milk and Their Effect on Cow Welfare and Reproductive Performance Compared to Rectal Pregnancy Tests 40 to 45 Days Post Insemination","volume":"3","author":"Lavon","year":"2022","journal-title":"Dairy"},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Ringa-O\u0161leja, G., Ant\u0101ne, V., L\u016bsis, I., Granti\u0146a-Ievi\u0146a, L., \u0160teingolde, \u017d., Mali\u0161evs, A., and B\u0113rzi\u0146\u0161, A. (2023). Reproduction and Productivity in Dairy Cattle after Abortions Both Related and Unrelated to Coxiella Burnetii. Animals, 13.","DOI":"10.3390\/ani13223561"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"117","DOI":"10.1016\/j.theriogenology.2018.08.001","article-title":"Comparison of Cow-Side Diagnostic Techniques for Subclinical Endometritis in Dairy Cows","volume":"120","author":"LeBlanc","year":"2018","journal-title":"Theriogenology"},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Y\u00e1\u00f1ez, U., Herrad\u00f3n, P.G., Becerra, J.J., Pe\u00f1a, A.I., and Quintela, L.A. (2022). Relationship between Postpartum Metabolic Status and Subclinical Endometritis in Dairy Cattle. Animals, 12.","DOI":"10.3390\/ani12030242"},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Szenci, O. (2021). Recent Possibilities for the Diagnosis of Early Pregnancy and Embryonic Mortality in Dairy Cows. Animals, 11.","DOI":"10.3390\/ani11061666"},{"key":"ref_17","unstructured":"Roberts, S.J. (1956). Veterinary Obstetrics and Genital Diseases, The Author. [1st ed.]."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"205","DOI":"10.1017\/S0021859600063164","article-title":"X-Ray Diagnosis of Pregnancy in Sheep with Special Reference to the Determination of the Number of Foetuses","volume":"63","author":"Ardran","year":"1964","journal-title":"J. Agric. Sci."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"37","DOI":"10.1016\/0921-4488(95)00644-Z","article-title":"Pregnancy Diagnosis in Sheep and Goats: A Review","volume":"17","author":"Ishwar","year":"1995","journal-title":"Small Rumin. Res."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"1135","DOI":"10.2527\/jas1976.4361135x","article-title":"Pregnancy Diagnosis in Ewes by Ultrasonic Scanning","volume":"43","author":"Lindahl","year":"1976","journal-title":"J. Anim. Sci."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"323","DOI":"10.1016\/0093-691X(78)90125-5","article-title":"Plasma Progesterone Levels as an Early Pregnancy Test in Beef Cattle","volume":"9","author":"Thirapatsukun","year":"1978","journal-title":"Theriogenology"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"261","DOI":"10.1016\/S0034-5288(18)32933-3","article-title":"A Test for Early Pregnancy in Sheep","volume":"26","author":"Morton","year":"1979","journal-title":"Res. Vet. Sci."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"83","DOI":"10.1095\/biolreprod46.1.83","article-title":"Radioimmunoassay of a Bovine Pregnancy-Associated Glycoprotein in Serum: Its Application for Pregnancy Diagnosis1","volume":"46","author":"Zoli","year":"1992","journal-title":"Biol. Reprod."},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Ioannidis, J., and Donadeu, F.X. (2017). Changes in Circulating microRNA Levels Can Be Identified as Early as Day 8 of Pregnancy in Cattle. PLoS ONE, 12.","DOI":"10.1371\/journal.pone.0174892"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"294","DOI":"10.1016\/j.rvsc.2017.06.001","article-title":"Serum microRNAs in Buffalo Cows: Potential Biomarkers of Pregnancy","volume":"115","author":"Guelfi","year":"2017","journal-title":"Res. Vet. Sci."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"100519","DOI":"10.1016\/j.atech.2024.100519","article-title":"RAPID: A Rabbit Pregnancy Diagnosis Device Based on Matrix Optical Sensing","volume":"8","author":"Lai","year":"2024","journal-title":"Smart Agric. Technol."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"107317","DOI":"10.1016\/j.anireprosci.2023.107317","article-title":"The Thermographic Monitoring in Early Pregnancy Detection in Holstein Cows and Heifers","volume":"256","author":"Kaya","year":"2023","journal-title":"Anim. Reprod. Sci."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"5","DOI":"10.1007\/s11250-010-9675-2","article-title":"Accuracy of Transrectal Palpation for Early Pregnancy Diagnosis in Egyptian Buffaloes","volume":"43","author":"Karen","year":"2011","journal-title":"Trop. Anim. Health Prod."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"263","DOI":"10.1111\/rda.14283","article-title":"Comparison of Ultrasonography, Progesterone Assay, Ballottement, and Non-return-to-heat with Digital Rectal Palpation Technique for Early Pregnancy Diagnosis in Red Sokoto Goat","volume":"58","author":"Bello","year":"2023","journal-title":"Reprod. Domest. Anim."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"378","DOI":"10.1111\/j.1751-0813.1975.tb15600.x","article-title":"The Diagnosis of Pregnancy in Sheep by Abdominal Palpation","volume":"51","author":"Pratt","year":"1975","journal-title":"Aust. Vet. J."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"196","DOI":"10.21608\/ejap.2014.93648","article-title":"Pregnancy Detection in Rabbits by Ultrasonography as Compared to Manual Palpation","volume":"51","author":"Khalil","year":"2014","journal-title":"Egypt. J. Anim. Prod."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"958540","DOI":"10.1155\/2013\/958540","article-title":"Early Pregnancy Diagnosis in Bovines: Current Status and Future Directions","volume":"2013","author":"Balhara","year":"2013","journal-title":"Sci. World J."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"65","DOI":"10.1016\/S0378-4320(01)00145-2","article-title":"Early Pregnancy Diagnosis in Swine by Direct Radioimmunoassay for Progesterone in Blood Spotted on Filter Paper","volume":"69","author":"Chadio","year":"2002","journal-title":"Anim. Reprod. Sci."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"1941","DOI":"10.1016\/S0093-691X(02)01289-X","article-title":"Early Pregnancy Diagnosis in Sheep by Progesterone and Pregnancy-Associated Glycoprotein Tests","volume":"59","author":"Karen","year":"2003","journal-title":"Theriogenology"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"3615","DOI":"10.3168\/jds.2018-15692","article-title":"Technical Note: Validation of an Automated in-Line Milk Progesterone Analysis System to Diagnose Pregnancy in Dairy Cattle","volume":"102","author":"Ambrose","year":"2019","journal-title":"J. Dairy Sci."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"455","DOI":"10.1111\/j.1439-0531.2010.01689.x","article-title":"Early Pregnancy Detection of Iraqi Riverine Buffalo (Bubalus bubalis) Using the BioPRYN Enzyme-Linked Immunosorbent Assay for PSPB and the Progesterone Assay","volume":"46","author":"Abdulkareem","year":"2011","journal-title":"Reprod. Domest. Anim."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"459","DOI":"10.1038\/249459a0","article-title":"Immunosuppression Detected in Pregnant Mice by Rosette Inhibition Test","volume":"249","author":"Morton","year":"1974","journal-title":"Nature"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"52","DOI":"10.1016\/S0007-1935(17)30591-2","article-title":"Early Pregnancy Factor: Biology and Practical Application","volume":"139","author":"Koch","year":"1983","journal-title":"Br. Vet. J."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"105","DOI":"10.1016\/j.theriogenology.2008.02.003","article-title":"Measurement of EPF for Detection of Cow Pregnancy Using Rosette Inhibition Test","volume":"70","author":"Pirany","year":"2008","journal-title":"Theriogenology"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"174","DOI":"10.1111\/j.8755-8920.2000.430307.x","article-title":"Study of Early Pregnancy Factor (EPF) in Equine (Equus caballus)","volume":"43","author":"Ohnuma","year":"2000","journal-title":"Am. J. Reprod. Immunol."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"385","DOI":"10.1530\/jrf.0.0570385","article-title":"Detection of Induced Death of Embryos in Sheep by the Rosette Inhibition Test","volume":"57","author":"Nancarrow","year":"1979","journal-title":"J. Reprod. Fertil."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"271","DOI":"10.1292\/jvms.55.271","article-title":"Monitoring Bovine Embryo Viability with Early Pregnancy Factor","volume":"55","author":"Sakonju","year":"1993","journal-title":"J. Vet. Med. Sci."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"23","DOI":"10.1016\/j.theriogenology.2024.08.004","article-title":"Detection of Sow Pregnancy in Day-20 Urine Samples Using Monoclonal Antibody against Synthesized Porcine Early Pregnancy Factor: Preliminary Results","volume":"229","author":"Park","year":"2024","journal-title":"Theriogenology"},{"key":"ref_44","first-page":"153","article-title":"Pregnancy-Associated Glycoproteins (PAG) as Pregnancy Markers in the Ruminants","volume":"57","author":"Sousa","year":"2006","journal-title":"J. Physiol. Pharmacol. Off. J. Pol. Physiol. Soc."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"6985","DOI":"10.3168\/jds.2022-21905","article-title":"Bayesian Estimation of Sensitivity and Specificity of a Milk Pregnancy-Associated Glycoprotein ELISA Test for Pregnancy Diagnosis between 23 and 27 Days after Insemination in Holstein Dairy Cows","volume":"105","author":"Durocher","year":"2022","journal-title":"J. Dairy Sci."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"4612","DOI":"10.3168\/jds.2007-0276","article-title":"Accuracy of a Pregnancy-Associated Glycoprotein ELISA to Determine Pregnancy Status of Lactating Dairy Cows Twenty-Seven Days After Timed Artificial Insemination","volume":"90","author":"Silva","year":"2007","journal-title":"J. Dairy Sci."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"717","DOI":"10.1016\/S0093-691X(99)00165-X","article-title":"Early Pregnancy Diagnosis in Goats by Determination of Pregnancy-Associated Glycoprotein Concentrations in Plasma Samples","volume":"52","author":"Sulon","year":"1999","journal-title":"Theriogenology"},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"73","DOI":"10.1016\/j.theriogenology.2017.04.021","article-title":"Pregnancy-Associated Glycoproteins (PAGs) Concentrations in Water Buffaloes (Bubalus bubalis) during Gestation and the Postpartum Period","volume":"97","author":"Barbato","year":"2017","journal-title":"Theriogenology"},{"key":"ref_49","doi-asserted-by":"crossref","unstructured":"L\u00f3pez-Gatius, F., Ganau, S., and Garcia-Ispierto, I. (2024). Evaluation of a Commercial Pregnancy Test Using Blood or Plasma Samples in High-Producing Dairy Cows. Animals, 14.","DOI":"10.3390\/ani14111656"},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"155","DOI":"10.1007\/s00253-025-13542-x","article-title":"Establishment of a Latex Immunochromatography for Detecting Bovine Early Pregnancy-Related Glycoproteins","volume":"109","author":"Gu","year":"2025","journal-title":"Appl. Microbiol. Biotechnol."},{"key":"ref_51","doi-asserted-by":"crossref","unstructured":"Bouroutzika, E., Theodosiadou, E.K., Proikakis, S., Valasi, I., and Tsangaris, G.T. (2025). Pregnancy-Associated Glycoproteins Identification in Skopelos Goat Milk by Means of Mass Spectrometry. Vet. Sci., 12.","DOI":"10.3390\/vetsci12111092"},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"e1345","DOI":"10.1002\/vms3.1345","article-title":"Serum Pregnancy-Associated Glycoprotein Profiles during Early Gestation in Karya and Konya Merino Sheep","volume":"10","author":"Kaya","year":"2024","journal-title":"Vet. Med. Sci."},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"100672","DOI":"10.1016\/j.vas.2026.100672","article-title":"Pregnancy Diagnosis Based on Pregnancy-Associated Glycoproteins Detection in Dairy Cow Milk: Factors Influencing Measurement","volume":"32","author":"Bramante","year":"2026","journal-title":"Vet. Anim. Sci."},{"key":"ref_54","doi-asserted-by":"crossref","unstructured":"Ninomiya, C., Yoshino, H., Ishiguro-Oonuma, T., Iga, K., Kanazawa, T., Takahashi, T., and Kizaki, K. (2024). Potential of Circulating miRNA Biomarkers and Exosomes for Early Pregnancy Diagnoses in Cattle. Animals, 14.","DOI":"10.3390\/ani14111592"},{"key":"ref_55","doi-asserted-by":"crossref","first-page":"107833","DOI":"10.1016\/j.anireprosci.2025.107833","article-title":"Differences in microRNA within Plasma Extracellular Vesicles at Various Time Points during Early Pregnancy in Sheep Revealed by High-Throughput Sequencing Data","volume":"276","author":"Lv","year":"2025","journal-title":"Anim. Reprod. Sci."},{"key":"ref_56","doi-asserted-by":"crossref","first-page":"145706","DOI":"10.1016\/j.gene.2021.145706","article-title":"Screening and Identification of microRNAs from Plasma-Derived Extracellular Vesicles (EVs) of Dazu Black Goat (Capra hircus) in Early Pregnant Stages","volume":"790","author":"Zhao","year":"2021","journal-title":"Gene"},{"key":"ref_57","doi-asserted-by":"crossref","unstructured":"Hitit, M., Kose, M., Kaya, M.S., K\u0131rbas, M., Dursun, S., Alak, I., and Atli, M.O. (2022). Circulating miRNAs in Maternal Plasma as Potential Biomarkers of Early Pregnancy in Sheep. Front. Genet., 13.","DOI":"10.3389\/fgene.2022.929477"},{"key":"ref_58","doi-asserted-by":"crossref","first-page":"89","DOI":"10.1016\/j.theriogenology.2019.03.001","article-title":"MiRNA Profiling of Plasma-Derived Exosomes from Dairy Cows during Gestation","volume":"130","author":"Zhao","year":"2019","journal-title":"Theriogenology"},{"key":"ref_59","doi-asserted-by":"crossref","unstructured":"Batra, K., Sehrawat, A., Kumar, A., Singh, M., Kaur, R., Yadav, D.C., Singh, N., and Maan, S. (2024). Identification of Circulatory microRNA Based Biomarkers for Early Pregnancy Diagnosis in Buffalo. Front. Cell Dev. Biol., 12.","DOI":"10.3389\/fcell.2024.1386241"},{"key":"ref_60","doi-asserted-by":"crossref","first-page":"1336","DOI":"10.5713\/ab.22.0422","article-title":"Serum Exosomal miR-192 Serves as a Potential Detective Biomarker for Early Pregnancy Screening in Sows","volume":"36","author":"Gao","year":"2023","journal-title":"Anim. Biosci."},{"key":"ref_61","doi-asserted-by":"crossref","first-page":"106706","DOI":"10.1016\/j.domaniend.2021.106706","article-title":"Analysis of Circulating microRNA during Early Gestation in Japanese Black Cattle","volume":"79","author":"Ono","year":"2022","journal-title":"Domest. Anim. Endocrinol."},{"key":"ref_62","doi-asserted-by":"crossref","unstructured":"Miretti, S., Lecchi, C., Ceciliani, F., and Baratta, M. (2020). MicroRNAs as Biomarkers for Animal Health and Welfare in Livestock. Front. Vet. Sci., 7.","DOI":"10.3389\/fvets.2020.578193"},{"key":"ref_63","doi-asserted-by":"crossref","first-page":"159","DOI":"10.1017\/S0022029925100988","article-title":"Early Pregnancy Detection in Buffaloes Targeting Interferon-Stimulated Genes in Duplex RT-qPCR","volume":"92","author":"Sharma","year":"2025","journal-title":"J. Dairy Res."},{"key":"ref_64","doi-asserted-by":"crossref","first-page":"105959","DOI":"10.1016\/j.livsci.2026.105959","article-title":"A Plasma Metabolomics Analysis Reveals a Panel of Metabolic Biomarkers for Early Pregnancy Diagnosis in Hu Sheep","volume":"309","author":"Dai","year":"2026","journal-title":"Livest. Sci."},{"key":"ref_65","doi-asserted-by":"crossref","unstructured":"Rickard, J.P., Ryan, G., Hall, E., de Graaf, S.P., and Hermes, R. (2017). Using Transrectal Ultrasound to Examine the Effect of Exogenous Progesterone on Early Embryonic Loss in Sheep. PLoS ONE, 12.","DOI":"10.1371\/journal.pone.0183659"},{"key":"ref_66","doi-asserted-by":"crossref","first-page":"859","DOI":"10.1016\/j.theriogenology.2007.12.013","article-title":"In Utero Characterisation of Fetal Growth by Ultrasound Scanning in the Rabbit","volume":"69","author":"Laigre","year":"2008","journal-title":"Theriogenology"},{"key":"ref_67","doi-asserted-by":"crossref","first-page":"267","DOI":"10.1136\/vr.147.10.267","article-title":"Early Diagnosis of Pregnancy in Sows by Ultrasound Evaluation of Embryo Development and Uterine Echotexture","volume":"147","author":"Bigliardi","year":"2000","journal-title":"Vet. Rec."},{"key":"ref_68","doi-asserted-by":"crossref","first-page":"1034","DOI":"10.1016\/j.theriogenology.2006.02.044","article-title":"Early Pregnancy Diagnosis by Transrectal Ultrasonography in Dairy Cattle","volume":"66","author":"Romano","year":"2006","journal-title":"Theriogenology"},{"key":"ref_69","doi-asserted-by":"crossref","unstructured":"Wang, X., Wang, J., Gao, Z., Luo, X., Ding, Z., Chen, Y., Zhang, Z., Yin, H., Zhang, Y., and Liang, X. (2026). A Deep-Learning-Enhanced Ultrasonic Biosensing System for Artifact Suppression in Sow Pregnancy Diagnosis. Biosensors, 16.","DOI":"10.3390\/bios16020075"},{"key":"ref_70","doi-asserted-by":"crossref","first-page":"1745","DOI":"10.7863\/jum.2008.27.12.1745","article-title":"Doppler Ultrasound in Canine Pregnancy","volume":"27","author":"Blanco","year":"2008","journal-title":"J. Ultrasound Med."},{"key":"ref_71","doi-asserted-by":"crossref","first-page":"247","DOI":"10.1016\/j.theriogenology.2017.10.029","article-title":"Early Pregnancy Diagnosis in Ewes by Subjective Assessment of Luteal Vascularisation Using Colour Doppler Ultrasonography","volume":"106","author":"Arashiro","year":"2018","journal-title":"Theriogenology"},{"key":"ref_72","doi-asserted-by":"crossref","first-page":"106129","DOI":"10.1016\/j.anireprosci.2019.106129","article-title":"Accuracy of Subjective Evaluation of Luteal Blood Flow by Color Doppler Ultrasonography for Early Diagnosis of Pregnancy in Egyptian Buffalo","volume":"208","author":"Samir","year":"2019","journal-title":"Anim. Reprod. Sci."},{"key":"ref_73","doi-asserted-by":"crossref","first-page":"149","DOI":"10.1016\/j.cvfa.2015.09.005","article-title":"Ultrasonographic Doppler Use for Female Reproduction Management","volume":"32","author":"Bollwein","year":"2016","journal-title":"Vet. Clin. N. Am. Food Anim. Pract."},{"key":"ref_74","doi-asserted-by":"crossref","unstructured":"Fontes, P.L.P., and Oosthuizen, N. (2022). Applied Use of Doppler Ultrasonography in Bovine Reproduction. Front. Anim. Sci., 3.","DOI":"10.3389\/fanim.2022.912854"},{"key":"ref_75","doi-asserted-by":"crossref","unstructured":"De Silva, M., Wickramasingha, D., Abayalath, N., Alexander, B., Wijayagunawardane, M., Lee, K.F., and Kodithuwakku, S. (2024). Early Pregnancy Diagnosis in Cows Using Corpus Luteum Blood Flow Analysis Based on Colour Doppler Ultrasonography and mRNA Analysis. BMC Vet. Res., 20.","DOI":"10.1186\/s12917-024-04438-5"},{"key":"ref_76","doi-asserted-by":"crossref","first-page":"skac018","DOI":"10.1093\/jas\/skac018","article-title":"Luteal Color Doppler Ultrasonography and Pregnancy-Associated Glycoproteins as Early Pregnancy Diagnostic Tools and Predictors of Pregnancy Loss in Bos taurus Postpartum Beef Cows","volume":"100","author":"Holton","year":"2022","journal-title":"J. Anim. Sci."},{"key":"ref_77","doi-asserted-by":"crossref","first-page":"104","DOI":"10.1016\/j.theriogenology.2018.08.007","article-title":"Accuracy of Assessment of Luteal Morphology and Luteal Blood Flow for Prediction of Early Pregnancy in Goats","volume":"121","author":"Cosentino","year":"2018","journal-title":"Theriogenology"},{"key":"ref_78","doi-asserted-by":"crossref","first-page":"skaf166","DOI":"10.1093\/jas\/skaf166","article-title":"Computer Vision Analysis of Luteal Color Doppler Ultrasonography for Early and Automated Pregnancy Diagnosis in Bos taurus Beef Cows","volume":"103","author":"Fontes","year":"2025","journal-title":"J. Anim. Sci."},{"key":"ref_79","doi-asserted-by":"crossref","first-page":"131","DOI":"10.1117\/1.429979","article-title":"Light Scattering from Cells: The Contribution of the Nucleus and the Effects of Proliferative Status","volume":"5","author":"Mourant","year":"2000","journal-title":"J. Biomed. Opt."},{"key":"ref_80","doi-asserted-by":"crossref","first-page":"120251","DOI":"10.1016\/j.saa.2021.120251","article-title":"Early Pregnancy Diagnosis of Rabbits: A Non-Invasive Approach Using Vis-NIR Spatially Resolved Spectroscopy","volume":"264","author":"Yuan","year":"2022","journal-title":"Spectrochim. Acta. A Mol. Biomol. Spectrosc."},{"key":"ref_81","doi-asserted-by":"crossref","first-page":"107751","DOI":"10.1016\/j.compag.2023.107751","article-title":"Study on Wearable Pregnancy Diagnosis Device for Rabbits Based on Photoelectric Sensor","volume":"207","author":"Yuan","year":"2023","journal-title":"Comput. Electron. Agric."},{"key":"ref_82","doi-asserted-by":"crossref","first-page":"6973","DOI":"10.3168\/jds.2021-21171","article-title":"Detection of Nonpregnant Cows and Potential Embryo Losses by Color Doppler Ultrasound and Interferon-Stimulated Gene Expression in Grazing Dairy Cows","volume":"105","author":"Madoz","year":"2022","journal-title":"J. Dairy Sci."},{"key":"ref_83","doi-asserted-by":"crossref","first-page":"95","DOI":"10.1095\/biolreprod.114.121525","article-title":"Conceptus-Induced Changes in the Gene Expression of Blood Immune Cells and the Ultrasound-Accessed Luteal Function in Beef Cattle: How Early Can We Detect Pregnancy?","volume":"91","author":"Pugliesi","year":"2014","journal-title":"Biol. Reprod."},{"key":"ref_84","doi-asserted-by":"crossref","first-page":"31","DOI":"10.1016\/j.anireprosci.2015.05.005","article-title":"Comparison of a Commercial Bovine Pregnancy-Associated Glycoprotein ELISA Test and a Pregnancy-Associated Glycoprotein Radiomimmunoassay Test for Early Pregnancy Diagnosis in Dairy Cattle","volume":"159","author":"Karen","year":"2015","journal-title":"Anim. Reprod. Sci."},{"key":"ref_85","doi-asserted-by":"crossref","first-page":"993","DOI":"10.1016\/j.theriogenology.2009.06.020","article-title":"Validation of a New Pregnancy-Associated Glycoprotein Radioimmunoassay Method for the Detection of Early Pregnancy in Ewes","volume":"72","author":"Barbato","year":"2009","journal-title":"Theriogenology"},{"key":"ref_86","doi-asserted-by":"crossref","unstructured":"Kim, T., Choi, Y.-H., Hong, J.-S., Park, H.-J., Kim, Y.-M., Kim, J.-E., Lee, J.-H., Sa, S.-J., Jeong, Y.-D., and Kim, J.-S. (2025). Deep Learning-Enhanced Diagnosis of Sow Pregnancy Through Low-Frequency Ultrasound Imaging. Animals, 15.","DOI":"10.3390\/ani15030318"},{"key":"ref_87","doi-asserted-by":"crossref","first-page":"102152","DOI":"10.1016\/j.atech.2026.102152","article-title":"Successful Classification of Pregnant and Empty Ultrasound Imagery of Sheep Using Convolutional Neural Network","volume":"14","author":"Golledge","year":"2026","journal-title":"Smart Agric. Technol."},{"key":"ref_88","doi-asserted-by":"crossref","unstructured":"Cavallini, D., Giammarco, M., Buonaiuto, G., Vignola, G., De Matos Vettori, J., Lamanna, M., Prasinou, P., Colleluori, R., Formigoni, A., and Fusaro, I. (2025). Two Years of Precision Livestock Management: Harnessing Ear Tag Device Behavioral Data for Pregnancy Detection in Free-Range Dairy Cattle on Silage\/Hay-Mix Ration. Front. Anim. Sci., 6.","DOI":"10.3389\/fanim.2025.1547395"},{"key":"ref_89","doi-asserted-by":"crossref","first-page":"290","DOI":"10.1016\/j.compag.2017.06.003","article-title":"A Semi-Automatic and an Automatic Segmentation Algorithm to Remove the Internal Organs from Live Pig CT Images","volume":"140","author":"Xiberta","year":"2017","journal-title":"Comput. Electron. Agric."},{"key":"ref_90","doi-asserted-by":"crossref","unstructured":"Cao, X., Lu, Y., Yang, L., Zhu, G., Hu, X., Lu, X., Yin, J., Guo, P., and Zhang, Q. (2023). CT Image Segmentation of Meat Sheep Loin Based on Deep Learning. PLoS ONE, 18.","DOI":"10.1371\/journal.pone.0293764"},{"key":"ref_91","doi-asserted-by":"crossref","first-page":"102488","DOI":"10.1016\/j.media.2022.102488","article-title":"Robust Deep Learning-Based Semantic Organ Segmentation in Hyperspectral Images","volume":"80","author":"Seidlitz","year":"2022","journal-title":"Med. Image Anal."},{"key":"ref_92","doi-asserted-by":"crossref","unstructured":"Huang, L., Guo, H., Rao, Q., Hou, Z., Li, S., Qiu, S., Fan, X., and Wang, H. (2019). Body Dimension Measurements of Qinchuan Cattle with Transfer Learning from LiDAR Sensing. Sensors, 19.","DOI":"10.3390\/s19225046"},{"key":"ref_93","doi-asserted-by":"crossref","unstructured":"Omotara, G., Tousi, S.M.A., Decker, J., Brake, D., and DeSouza, G.N. (2024). High-Throughput and Accurate 3D Scanning of Cattle Using Time-of-Flight Sensors and Deep Learning. Sensors, 24.","DOI":"10.3390\/s24165275"},{"key":"ref_94","doi-asserted-by":"crossref","first-page":"101527","DOI":"10.1016\/j.animal.2025.101527","article-title":"Review: Emerging Sensors and Instrumentation Systems for Bovine Health Monitoring","volume":"19","author":"Ferreira","year":"2025","journal-title":"Animal"},{"key":"ref_95","doi-asserted-by":"crossref","unstructured":"Lamanna, M., Polizzi, G., Bovo, M., and Cavallini, D. (2026). Precision Livestock Farming for Dairy Cows. Encyclopedia of Livestock Medicine for Large Animal and Poultry Production, Springer.","DOI":"10.1007\/978-3-031-52133-1_598-1"},{"key":"ref_96","doi-asserted-by":"crossref","first-page":"1928","DOI":"10.3168\/jds.2012-6107","article-title":"Invited Review: Sensors to Support Health Management on Dairy Farms","volume":"96","author":"Rutten","year":"2013","journal-title":"J. Dairy Sci."},{"key":"ref_97","doi-asserted-by":"crossref","unstructured":"Yu, Z., Han, Y., Cha, L., Chen, S., Wang, Z., and Zhang, Y. (2024). Design of an Intelligent Wearable Device for Real-Time Cattle Health Monitoring. Front. Robot. AI, 11.","DOI":"10.3389\/frobt.2024.1441960"},{"key":"ref_98","doi-asserted-by":"crossref","first-page":"685","DOI":"10.1016\/S0093-691X(01)00600-8","article-title":"Increase in Milk and Body Temperature of Cows as a Sign of Embryo Entry into the Uterus","volume":"56","author":"Gil","year":"2001","journal-title":"Theriogenology"}],"container-title":["Animals"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2076-2615\/16\/18\/2897\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,9,15]],"date-time":"2026-09-15T08:50:50Z","timestamp":1789462250000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2076-2615\/16\/18\/2897"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,9,15]]},"references-count":98,"journal-issue":{"issue":"18","published-online":{"date-parts":[[2026,9]]}},"alternative-id":["ani16182897"],"URL":"https:\/\/doi.org\/10.3390\/ani16182897","relation":{},"ISSN":["2076-2615"],"issn-type":[{"value":"2076-2615","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,9,15]]}}}