{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,8]],"date-time":"2026-04-08T04:26:29Z","timestamp":1775622389655,"version":"3.50.1"},"reference-count":27,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2024,4,25]],"date-time":"2024-04-25T00:00:00Z","timestamp":1714003200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Israeli Chief scientist of Agriculture","award":["3144000629"],"award-info":[{"award-number":["3144000629"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>The most reliable methods for pregnancy diagnosis in dairy herds include rectal palpation, ultrasound examination, and evaluation of plasma progesterone concentrations. However, these methods are expensive, labor-intensive, and invasive. Thus, there is a need to develop a practical, non-invasive, cost-effective method that can be implemented on the farm to detect pregnancy. This study suggests employing microwave dielectric spectroscopy (MDS, 0.5\u201340 GHz) as a method to evaluate reproduction events in dairy cows. The approach involves the integration of MDS data with information on milk solids to detect pregnancy and identify early embryonic loss in dairy cows. To test the ability to predict pregnancy according to these measurements, milk samples were collected from (i) pregnant and non-pregnant randomly selected cows, (ii) weekly from selected cows (n = 12) before insemination until a positive pregnancy test, and (iii) daily from selected cows (n = 10) prior to insemination until a positive pregnancy test. The results indicated that the dielectric strength of \u0394\u03b5 and the relaxation time, \u03c4, exhibited reduced variability in the case of a positive pregnancy diagnosis. Using principal component analysis (PCA), a clear distinction between pregnancy and nonpregnancy status was observed, with improved differentiation upon a higher sampling frequency. Additionally, a neural network machine learning technique was employed to develop a prediction algorithm with an accuracy of 73%. These findings demonstrate that MDS can be used to detect changes in milk upon pregnancy. The developed machine learning provides a broad classification that could be further enhanced with additional data.<\/jats:p>","DOI":"10.3390\/s24092742","type":"journal-article","created":{"date-parts":[[2024,4,25]],"date-time":"2024-04-25T08:08:32Z","timestamp":1714032512000},"page":"2742","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["Microwave Dielectric Response of Bovine Milk as Pregnancy Detection Tool in Dairy Cows"],"prefix":"10.3390","volume":"24","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-9491-4801","authenticated-orcid":false,"given":"Cindy","family":"Galindo","sequence":"first","affiliation":[{"name":"Institute of Applied Physics, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel"}]},{"given":"Guy","family":"Levy","sequence":"additional","affiliation":[{"name":"Institute of Applied Physics, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel"}]},{"given":"Yuri","family":"Feldman","sequence":"additional","affiliation":[{"name":"Institute of Applied Physics, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel"}]},{"given":"Zvi","family":"Roth","sequence":"additional","affiliation":[{"name":"Animal Science Department, The Robert H. Smith Faculty of Agriculture, Food, and Environment, The Hebrew University of Jerusalem, Rehovot 7610001, Israel"}]},{"given":"Jonathan","family":"Shalev","sequence":"additional","affiliation":[{"name":"Animal Science Department, The Robert H. Smith Faculty of Agriculture, Food, and Environment, The Hebrew University of Jerusalem, Rehovot 7610001, Israel"}]},{"given":"Chen","family":"Raz","sequence":"additional","affiliation":[{"name":"Animal Science Department, The Robert H. Smith Faculty of Agriculture, Food, and Environment, The Hebrew University of Jerusalem, Rehovot 7610001, Israel"}]},{"given":"Edo","family":"Mor","sequence":"additional","affiliation":[{"name":"The Racah Institute of Physics, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel"}]},{"given":"Nurit","family":"Argov-Argaman","sequence":"additional","affiliation":[{"name":"Animal Science Department, The Robert H. Smith Faculty of Agriculture, Food, and Environment, The Hebrew University of Jerusalem, Rehovot 7610001, Israel"}]}],"member":"1968","published-online":{"date-parts":[[2024,4,25]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1821","DOI":"10.3402\/fnr.v52i0.1821","article-title":"Fatty acids in bovine milk fat","volume":"52","year":"2008","journal-title":"Food Nutr. Res."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"672","DOI":"10.1126\/science.1178085","article-title":"Water Freezes Differently on Positively and Negatively Charged Surfaces of Pyroelectric Materials","volume":"327","author":"Ehre","year":"2010","journal-title":"Science"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"12301","DOI":"10.1073\/pnas.0604897103","article-title":"Solute-induced retardation of water dynamics probed directly by terahertz spectroscopy","volume":"103","author":"Heugen","year":"2006","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1663","DOI":"10.1088\/0031-9155\/35\/12\/006","article-title":"On the existence of bound water in biological systems as probed by dielectric spectroscopy","volume":"35","author":"Kaatze","year":"1990","journal-title":"Phys. Med. Biol."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1923","DOI":"10.1007\/s00396-014-3296-7","article-title":"The dielectric response of interfacial water\u2014From the ordered structures to the single hydrated shell","volume":"292","author":"Feldman","year":"2014","journal-title":"Colloid Polym. Sci."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"390","DOI":"10.1016\/j.colsurfb.2016.01.031","article-title":"Dielectric spectroscopy study of water dynamics in frozen bovine milk","volume":"141","author":"Agranovich","year":"2016","journal-title":"Colloids Surf B Biointerfaces"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"391","DOI":"10.1016\/j.colsurfb.2017.03.051","article-title":"Microwave dielectric spectroscopy study of water dynamics in normal and contaminated raw bovine milk","volume":"154","author":"Agranovich","year":"2017","journal-title":"Colloids Surf B Biointerfaces"},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Raicu, V., and Feldman, Y. (2015). Dielectric Relaxation in Biological Systems: Physical Principles, Methods, and Applications, Oxford University Press.","DOI":"10.1093\/acprof:oso\/9780199686513.001.0001"},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Raicu, V., and Feldman, Y. (2015). Dielectric Relaxation in Biological Systems, Oxford University.","DOI":"10.1093\/acprof:oso\/9780199686513.001.0001"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"15428","DOI":"10.1039\/C5CP01871D","article-title":"What is the primary mover of water dynamics?","volume":"17","author":"Tripathi","year":"2015","journal-title":"Phys. Chem. Chem. Phys."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"13941","DOI":"10.1039\/C6CP02195F","article-title":"The mechanism of the dielectric relaxation in water","volume":"18","author":"Popov","year":"2016","journal-title":"Phys. Chem. Chem. Phys."},{"key":"ref_12","unstructured":"Bottcher, C.J.F., and Bordewijk, P. (1978). Theory of Electric Polarization, Volume II: Dielectrics in Time-Dependent Fields, Elsevier Science."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"2863","DOI":"10.3168\/jds.2016-11736","article-title":"Assessing the effect of pregnancy stage on milk composition of dairy cows using mid-infrared spectra","volume":"100","author":"Bastin","year":"2017","journal-title":"J. Dairy Sci."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"596","DOI":"10.3389\/fendo.2020.00596","article-title":"Progesterone Regulation of Milk Fat Globule Size Is VLDL Dependent","volume":"11","author":"Raz","year":"2020","journal-title":"Front. Endocrinol."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"226","DOI":"10.1590\/S1806-92902015000600005","article-title":"Methodology to estimate the cost of delayed pregnancy for dairy cows. An example for Argentina","volume":"44","author":"Cattaneo","year":"2015","journal-title":"Rev. Bras. De Zootec."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"2139","DOI":"10.3168\/jds.S0022-0302(98)75790-X","article-title":"Effect of Time of Artificial Insemination on Pregnancy Rates, Calving Rates, Pregnancy Loss, and Gender Ratio After Synchronization of Ovulation in Lactating Dairy Cows","volume":"81","author":"Silcox","year":"1998","journal-title":"J. Dairy Sci."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"147","DOI":"10.1016\/j.theriogenology.2017.05.024","article-title":"Dynamics of pre- and post-insemination progesterone profiles and insemination outcomes determined by an in-line milk analysis system in primiparous and multiparous Canadian Holstein cows","volume":"102","author":"Gobikrushanth","year":"2017","journal-title":"Theriogenology"},{"key":"ref_18","unstructured":"Keysight Technologies (2020). N1501A Dielectric Probe Kit. Technical Overview, Keysight Technologies."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"136730","DOI":"10.1016\/j.foodchem.2023.136730","article-title":"The role of milk fat globule size in modulating the composition of postbiotics produced by Bacillus subtilis and their effect on mammary epithelial cells","volume":"427","author":"Raz","year":"2023","journal-title":"Food Chem."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"755","DOI":"10.1088\/0957-0233\/15\/4\/020","article-title":"Dielectric spectroscopy data treatment: I. Frequency domain","volume":"15","author":"Axelrod","year":"2004","journal-title":"Meas. Sci. Technol."},{"key":"ref_21","unstructured":"Klambauer, G., Unterthiner, T., Mayr, A., and Hochreiter, S. (2017, January 4\u20139). Self-Normalizing Neural Networks. Proceedings of the 31st International Conference on Neural Information Processing Systems, Long Beach, CA, USA."},{"key":"ref_22","unstructured":"(2022, May 31). Wolfram Research (2016), CrossEntropyLossLayer, Wolfram Language Function. Available online: https:\/\/reference.wolfram.com\/language\/ref\/CrossEntropyLossLayer.html."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"12385","DOI":"10.1021\/acs.chemrev.7b00259","article-title":"How Water\u2019s Properties Are Encoded in Its Molecular Structure and Energies","volume":"117","author":"Brini","year":"2017","journal-title":"Chem. Rev."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"2749","DOI":"10.3168\/jds.2018-15507","article-title":"Symposium review: Fat globules in milk and their structural modifications during gastrointestinal digestion","volume":"102","author":"Singh","year":"2019","journal-title":"J. Dairy Sci."},{"key":"ref_25","unstructured":"Melton, L., Shahidi, F., and Varelis, P. (2019). Encyclopedia of Food Chemistry, Academic Press."},{"key":"ref_26","unstructured":"James, G., Witten, D., Hastie, T., and Tibshirani, R. (2017). An Introduction to Statistical Learning with Applications in R, Springer."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"909","DOI":"10.1016\/j.idairyj.2004.03.005","article-title":"Milk fat globule size is affected by fat production in dairy cows","volume":"14","author":"Lars","year":"2004","journal-title":"Int. Dairy J."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/24\/9\/2742\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T14:32:59Z","timestamp":1760106779000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/24\/9\/2742"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,4,25]]},"references-count":27,"journal-issue":{"issue":"9","published-online":{"date-parts":[[2024,5]]}},"alternative-id":["s24092742"],"URL":"https:\/\/doi.org\/10.3390\/s24092742","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2024,4,25]]}}}