{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,24]],"date-time":"2026-02-24T21:04:35Z","timestamp":1771967075517,"version":"3.50.1"},"reference-count":56,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2025,8,22]],"date-time":"2025-08-22T00:00:00Z","timestamp":1755820800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"University of Porto and the Dairy Unit of the Dire\u00e7\u00e3o Regional de Agricultura do Entre-Douro e Minho (DRAEDM) of the Ministry of Agriculture, Portugal"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Veterinary Sciences"],"abstract":"<jats:p>High temperature typically decreases feed intake, milk production, and efficiency and increases metabolic disorders and health problems, greatly impacting farm economics. Supplements based on Saccharomyces cerevisiae have been suggested to benefit cows under heat stress, but effects on dairy cow performance are contradictory. This study aimed to evaluate the influence of heat stress on the effects of live yeast supplementation on the performance of dairy cows. Environmental temperature parameters were compared to two thermal humidity indices (THI1 and THI2) using wet bulb or dew point temperatures, as explanatory variables of dairy cow performance during the hot season. The experiment followed a randomized complete block design with 12 Holstein cows blocked by lactation number, days in milk, and milk production (two cows per block) and within each block, each cow was randomly assigned to a maize silage-based TMR with a concentrate mixture containing no yeast culture (Control) or 1 g\/kg concentrate dry matter of a live yeast culture based on S. cerevisiae (Yeast) for 35 days. The experiment lasted for 35 d. Dry matter intake (DMI) was significantly higher for Yeast than it was for Control for all classes of temperature and THIs studied with an average increase of 2 kg DM per day, except for mean THI1 (from 54 to 60), for which the DMI was similar between treatments. Yeast promoted significantly higher milk yield than Control for all classes of daily maximum and mean temperature, averaging an increase of 4 kg of milk per day. Results suggest a more marked effect of temperature and indicate that yeast supplementation improved lactation performance of dairy cows exposed to hot weather.<\/jats:p>","DOI":"10.3390\/vetsci12090791","type":"journal-article","created":{"date-parts":[[2025,8,22]],"date-time":"2025-08-22T13:47:49Z","timestamp":1755870469000},"page":"791","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["Live Yeast Supplementation Attenuates the Effects of Heat Stress in Dairy Cows"],"prefix":"10.3390","volume":"12","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-1904-0358","authenticated-orcid":false,"given":"Ana R. J.","family":"Cabrita","sequence":"first","affiliation":[{"name":"REQUIMTE, LAQV, ICBAS, School of Medicine and Biomedical Sciences, University of Porto, Rua Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6882-0334","authenticated-orcid":false,"given":"J\u00falio","family":"Carvalheira","sequence":"additional","affiliation":[{"name":"CIBIO, ICBAS, School of Medicine and Biomedical Sciences, University of Porto, Rua Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6237-417X","authenticated-orcid":false,"given":"Ant\u00f3nio J. M.","family":"Fonseca","sequence":"additional","affiliation":[{"name":"REQUIMTE, LAQV, ICBAS, School of Medicine and Biomedical Sciences, University of Porto, Rua Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2025,8,22]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Oliveira, C.P., Sousa, F.C., Silva, A.L., Schultz, \u00c9.B., Valderrama Londo\u00f1o, R.I., and Souza, P.A.R. (2025). Heat stress in dairy cows: Impacts, identification, and mitigation strategies\u2014A review. Animals, 15.","DOI":"10.3390\/ani15020249"},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Cartwright, S.L., Schmied, J., Karrow, N., and Mallard, B.A. (2023). Impact of heat stress on dairy cattle and selection strategies for thermotolerance: A review. Front. Vet. Sci., 10.","DOI":"10.3389\/fvets.2023.1198697"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"e06202","DOI":"10.1016\/j.heliyon.2021.e06202","article-title":"Influence of heat stress on milk production and its financial implications in semi-arid areas of South Africa","volume":"7","author":"Ogundeji","year":"2021","journal-title":"Heliyon"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"E52","DOI":"10.3168\/jds.S0022-0302(03)74040-5","article-title":"Economic losses from heat stress by US livestock industries","volume":"86","author":"Cobanov","year":"2003","journal-title":"J. Dairy Sci."},{"key":"ref_5","first-page":"E110","article-title":"Environmental stress in confined beef cattle","volume":"81","author":"Mader","year":"2003","journal-title":"J. Anim. Sci."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1947","DOI":"10.3168\/jds.2006-513","article-title":"Temperature-humidity indices as indicators of milk production losses due to heat stress","volume":"90","author":"Bohmanova","year":"2007","journal-title":"J. Dairy Sci."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"223","DOI":"10.1016\/j.livsci.2006.06.011","article-title":"Utility of on- and off-farm weather records for studies in genetics of heat tolerance","volume":"105","author":"Freitas","year":"2006","journal-title":"Livest. Sci."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1586","DOI":"10.3168\/jds.S0022-0302(02)74228-8","article-title":"Studies on genetics of heat tolerance in dairy cattle with reduced weather information via cluster analysis","volume":"85","author":"Ravagnolo","year":"2002","journal-title":"J. Dairy Sci."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"110517","DOI":"10.1016\/j.compag.2025.110517","article-title":"Navigating the Labyrinth of heat stress assessment in dairy cattle: A comprehensive review of methods and emerging technologies","volume":"237","author":"Singaravadivelan","year":"2025","journal-title":"Comput. Electron. Agric."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"2044","DOI":"10.3168\/jds.S0022-0302(94)77149-6","article-title":"Heat stress interaction with shade and cooling","volume":"77","author":"Armstrong","year":"1994","journal-title":"J. Dairy Sci."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"2080","DOI":"10.3168\/jds.S0022-0302(94)77151-4","article-title":"Heat stress interactions with protein, supplemental fat, and fungal cultures","volume":"77","author":"Huber","year":"1994","journal-title":"J. Dairy Sci."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"2131","DOI":"10.3168\/jds.S0022-0302(03)73803-X","article-title":"Effects of heat-stress on production in dairy cattle","volume":"86","author":"West","year":"2003","journal-title":"J. Dairy Sci."},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Kim, S.H., Ramos, S.C., Valencia, R.A., Cho, Y.I., and Lee, S.S. (2022). Heat stress: Effects on rumen microbes and host physiology, and strategies to alleviate the negative impacts on lactating dairy cows. Front. Microbiol., 13.","DOI":"10.3389\/fmicb.2022.804562"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"123","DOI":"10.3168\/jds.S0022-0302(00)74863-6","article-title":"Effects of yeast culture (Saccharomyces cerevisiae) on prepartum intake and postpartum intake and milk production of Jersey cows","volume":"83","author":"Dann","year":"2000","journal-title":"J. Dairy Sci."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"343","DOI":"10.3168\/jds.2007-0839","article-title":"The effects of live yeast supplementation to dairy cows during the hot season on production, feed efficiency, and digestibility","volume":"92","author":"Moallem","year":"2009","journal-title":"J. Dairy Sci."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"4062","DOI":"10.3168\/jds.2014-9215","article-title":"Response of lactating cows to live yeast supplementation during summer","volume":"98","author":"Salvati","year":"2015","journal-title":"J. Dairy Sci."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"175","DOI":"10.1016\/j.anifeedsci.2008.09.001","article-title":"Effect of feeding Saccharomyces Cerevisiae on performance of dairy cows during summer heat stress","volume":"150","author":"Bruno","year":"2009","journal-title":"Anim. Feed Sci. Technol."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"4495","DOI":"10.3168\/jds.2023-24194","article-title":"Dietary supplementation with live or autolyzed yeast: Effects on performance, nutrient digestibility, and ruminal fermentation in dairy cows","volume":"107","author":"Takiya","year":"2024","journal-title":"J. Dairy Sci."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"656","DOI":"10.1071\/AN15356","article-title":"Effects of dietary active dried yeast (Saccharomyces cerevisiae) supply at two levels of concentrate on energy and nitrogen utilisation and methane emissions of lactating dairy cows","volume":"57","author":"Wills","year":"2017","journal-title":"Anim. Prod. Sci."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"3528","DOI":"10.3168\/jds.2007-0889","article-title":"How Does Live Yeast Differ from Sodium Bicarbonate to Stabilize Ruminal pH in High-Yielding Dairy Cows?","volume":"91","author":"Marden","year":"2008","journal-title":"J. Dairy Sci."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"325","DOI":"10.3168\/jds.2016-11263","article-title":"Effects of the dose and viability of Saccharomyces cerevisiae. 1. Diversity of ruminal microbes as analyzed by Illumina MiSeq sequencing and quantitative PCR","volume":"100","author":"Jiang","year":"2017","journal-title":"J. Dairy Sci."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"325","DOI":"10.3168\/jds.2019-17303","article-title":"Effects of feeding live yeast at 2 dosages on performance and feeding behavior of dairy cows under heat stress","volume":"103","author":"Perdomo","year":"2020","journal-title":"J. Dairy Sci."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"201","DOI":"10.3168\/jds.2017-13241","article-title":"Effect of supplemental yeast culture and dietary starch content on rumen fermentation and digestion in dairy cows","volume":"101","author":"Dias","year":"2018","journal-title":"J. Dairy Sci."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"6591","DOI":"10.3168\/jds.2012-5377","article-title":"Effects of Saccharomyces cerevisiae fermentation product on ruminal starch digestion are dependent upon dry matter intake for lactating cows","volume":"95","author":"Allen","year":"2012","journal-title":"J. Dairy Sci."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"186","DOI":"10.3168\/jds.2017-13240","article-title":"Effects of supplementing yeast culture to diets differing in starch content on performance and feeding behavior of dairy cows","volume":"101","author":"Dias","year":"2018","journal-title":"J. Dairy Sci."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"146","DOI":"10.1016\/j.anifeedsci.2006.09.011","article-title":"Daily rumen pH pattern of loose-housed dairy cattle as affected by feeding pattern and live yeast supplementation","volume":"136","author":"Bach","year":"2007","journal-title":"Anim. Feed Sci. Technol."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"6499","DOI":"10.3168\/jds.2014-8226","article-title":"Modification of the feeding behavior of dairy cows through live yeast supplementation","volume":"97","author":"DeVries","year":"2014","journal-title":"J. Dairy Sci."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"1345","DOI":"10.3168\/jds.S0022-0302(98)75697-8","article-title":"Effect of yeast on feed intake and performance of cows fed diets based on corn silage during early lactation","volume":"81","author":"Wohlt","year":"1998","journal-title":"J. Dairy Sci."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"2992","DOI":"10.2527\/1994.72112992x","article-title":"Ruminal microbiology, biotechnology, and ruminant nutrition: Progress and problems","volume":"72","author":"Wallace","year":"1994","journal-title":"J. Anim. Sci."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"2717","DOI":"10.3168\/jds.S0022-0302(93)77608-0","article-title":"Effects of yeast on dairy cow performance, ruminal fermentation, blood components, and milk manufacturing properties","volume":"76","author":"Piva","year":"1993","journal-title":"J. Dairy Sci."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"5","DOI":"10.1016\/j.anifeedsci.2007.04.019","article-title":"Effects of active dry yeasts on the rumen microbial ecosystem: Past, present and future","volume":"145","author":"Walker","year":"2008","journal-title":"Anim. Feed Sci. Technol."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"303","DOI":"10.4103\/0976-500X.119726","article-title":"How to calculate sample size in animal studies?","volume":"4","author":"Charan","year":"2013","journal-title":"J. Pharmacol. Pharmacother."},{"key":"ref_33","unstructured":"Horwitz, W. (2000). Official Methods of Analysis of AOAC International, AOAC International."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"251","DOI":"10.1038\/195251a0","article-title":"Relative Importance of Dry- and Wet-Bulb Temperatures in Causing Heat Stress in Cattle","volume":"195","author":"Bianca","year":"1962","journal-title":"Nature"},{"key":"ref_35","unstructured":"Yousef, M.K. (1985). Stress Physiology in Livestock. Volume I. Basic Principles, CRC Press."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"3583","DOI":"10.3168\/jds.S0022-0302(91)78551-2","article-title":"Methods for dietary fiber, neutral detergent fiber, and nonstarch polysaccharides in relation to animal nutrition","volume":"74","author":"Robertson","year":"1991","journal-title":"J. Dairy Sci."},{"key":"ref_37","unstructured":"James, W., and Teander, O. (1981). The detergent system of analysis. The Analysis of Dietary Fiber in Food, Marcel Dekker Inc."},{"key":"ref_38","unstructured":"Norma Portuguesa (1997). Norma Portuguesa 873: Alimentos para Animais, Determina\u00e7\u00e3o do teor de F\u00f3sforo, M\u00e9todo Gravim\u00e9trico, Norma Portuguesa."},{"key":"ref_39","unstructured":"Norma Portuguesa (1985). Norma Portuguesa 1786: Alimentos para Animais, Determina\u00e7\u00e3o do teor de C\u00e1lcio, M\u00e9todo Volum\u00e9trico, Processo Corrente, Norma Portuguesa."},{"key":"ref_40","first-page":"111","article-title":"Chemical characterization of some swedish cereal whole meal and bran fractions","volume":"14","author":"Salomonsson","year":"1984","journal-title":"Swed. J. Agric. Res."},{"key":"ref_41","unstructured":"Norma Portuguesa (1986). Norma Portuguesa 3255: Determina\u00e7\u00e3o do teor de Ureia. M\u00e9todo Espectrofotom\u00e9trico, Norma Portuguesa."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"8645","DOI":"10.3168\/jds.2017-12651","article-title":"Invited review: Effects of heat stress on dairy cattle welfare","volume":"100","author":"Polsky","year":"2017","journal-title":"J. Dairy Sci."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"659","DOI":"10.1016\/j.theriogenology.2015.04.021","article-title":"Seasonal heat stress: Clinical implications and hormone treatments for the fertility of dairy cows","volume":"84","year":"2015","journal-title":"Theriogenology"},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"226","DOI":"10.1007\/BF01041833","article-title":"Influence of weather conditions on milk production and rectal temperature of Holsteins fed two levels of concentrate","volume":"34","author":"Kabuga","year":"1991","journal-title":"Int. J. Biometeorol."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"44","DOI":"10.1111\/j.1749-6632.1955.tb36544.x","article-title":"Neural regulation of food intake","volume":"63","author":"Brobeck","year":"1955","journal-title":"Ann. N. Y. Acad. Sci."},{"key":"ref_46","first-page":"6","article-title":"Heat stress survey","volume":"33","author":"Oliver","year":"1979","journal-title":"Calif. Agric."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"21","DOI":"10.2527\/1997.77suppl_221x","article-title":"Nutritional strategies for managing the heat-stressed dairy cow","volume":"77","author":"West","year":"1999","journal-title":"J. Anim. Sci."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"1133","DOI":"10.3168\/jds.S0022-0302(72)85635-2","article-title":"Effect of summer weather on performance of Holstein cows in three stages of lactation","volume":"55","author":"Maust","year":"1972","journal-title":"J. Dairy Sci."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"776","DOI":"10.2527\/jas1972.345776x","article-title":"Effect of prolonged thermal exposure on growth hormone (GH) secretion in cattle","volume":"34","author":"Mitra","year":"1972","journal-title":"J. Anim. Sci."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"1986","DOI":"10.3168\/jds.2008-1641","article-title":"Effects of heat stress and plane of nutrition on lactating Holstein cows: I. Production, metabolism, and aspects of circulating somatotropin","volume":"92","author":"Rhoads","year":"2009","journal-title":"J. Dairy Sci."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"644","DOI":"10.3168\/jds.2009-2295","article-title":"Effects of heat stress on energetic metabolism in lactating Holstein cows","volume":"93","author":"Wheelock","year":"2010","journal-title":"J. Dairy Sci."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"1594","DOI":"10.2527\/jas1983.5761594x","article-title":"Ruminant heat stress: Effect on production and means of alleviation","volume":"57","author":"Morrison","year":"1983","journal-title":"J. Anim. Sci."},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"3085","DOI":"10.3168\/jds.S0022-0302(98)75873-4","article-title":"Accounting for the effects of environment on the nutrient requirements of dairy cattle","volume":"81","author":"Fox","year":"1998","journal-title":"J. Dairy Sci."},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"43","DOI":"10.1016\/j.biosystemseng.2019.11.005","article-title":"Modelling of heat stress in a robotic dairy farm. Part 2: Identifying the specific thresholds with production factors","volume":"199","author":"Ji","year":"2020","journal-title":"Biosyst. Eng."},{"key":"ref_55","doi-asserted-by":"crossref","unstructured":"Neethirajan, S. (2020). The role of sensors, big data and machine learning in modern animal farming. Sens. Bio-Sens. Res., 29.","DOI":"10.1016\/j.sbsr.2020.100367"},{"key":"ref_56","doi-asserted-by":"crossref","unstructured":"Sejian, V., Shashank, C.G., Silpa, M.V., Madhusoodan, A.P., Devaraj, C., and Koenig, S. (2022). Non-invasive methods of quantifying heat stress response in farm animals with special reference to dairy cattle. Atmosphere, 13.","DOI":"10.3390\/atmos13101642"}],"container-title":["Veterinary Sciences"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2306-7381\/12\/9\/791\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,9]],"date-time":"2025-10-09T18:34:00Z","timestamp":1760034840000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2306-7381\/12\/9\/791"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,8,22]]},"references-count":56,"journal-issue":{"issue":"9","published-online":{"date-parts":[[2025,9]]}},"alternative-id":["vetsci12090791"],"URL":"https:\/\/doi.org\/10.3390\/vetsci12090791","relation":{},"ISSN":["2306-7381"],"issn-type":[{"value":"2306-7381","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,8,22]]}}}