Understanding heat stress in pasture‑based dairy cows: Challenges and innovations from thermal indices to multivariate sensor technologies
Barra lateral del artículo
Contenido principal del artículo
https://orcid.org/0000-0002-3215-5379
Resumen
Heat stress is an increasingly critical challenge for modern dairy production, particularly in pasture‑based systems where cows are directly exposed to solar radiation, humidity, wind, and high temperatures. This review synthesises the current evidence on environmental thermal indices, physiological responses, behavioural adaptations, and sensor-based technologies relevant to heat stress assessment in grazing dairy cattle. A narrative review of peer-reviewed and grey literature (2015–2026) was conducted across major scientific databases, focusing on studies that developed or validated thermal indices, compared them with animal-based indicators, or quantified their impacts on performance and health. The findings show that the Temperature Humidity Index (THI), although widely used, has limited accuracy in outdoor conditions owing to its exclusion of solar radiation and wind. Updated indices, including the adjusted THI, Heat Load Index (HLI), Comprehensive Climate Index (CCI), Dairy Heat Load Index (DHLI), and Grazing Heat Load Index (GHLI), demonstrate better alignment with physiological responses under grazing conditions. Early and sensitive indicators, such as respiratory rate (RR), panting, and rising body temperature (BT), provide direct insight into the loss of thermal balance, whereas reductions in rumination, shifts in feeding behaviour, and increased shade-seeking reflect behavioural adaptation. Emerging evidence also highlights heat-induced dysbiosis in the rumen and intestinal microbiome, with implications for metabolism, immunity, and reproductive function. Sensor-based technologies, including rumen boluses, infrared thermography, accelerometers, and subcutaneous or vaginal temperature devices, enhance real-time monitoring and support early detection, particularly in extensive outdoor environments. Overall, integrating multivariable climate indices with animal-centred physiological and behavioural monitoring provides a more accurate and responsive framework for heat stress detection, risk assessment, and management in pasture-based dairy systems, supporting productivity, welfare, and long-term system resilience.
Detalles del artículo
Esta obra está bajo una licencia internacional Creative Commons Atribución 4.0.
Referencias
Arias, R.A., Delgado, C., Keim, J.P., & Gandarillas, M. (2021). Use of the comprehensive climate index to estimate heat stress response of grazing dairy cows in a temperate climate region. Journal of Dairy Research, 88(2), 154-161. https://doi.org/10.1017/S0022029921000406
Arias, R.A., Heinsohn, J., Keim, J.P., Pinto, R., & Bombal, E. (2025). Perception of Chilean dairy farmers facing the growing heat stress events in the country. Austral Journal of Veterinary Sciences, 57, e5704. https://doi.org/10.4206/ajvs.57.04
Arias, R.A., Herrera, C., Larraín, R., González, F., Mader, T.L., & Velásquez, A. (2018). Physiological and behavioural response of two dairy cows’ genotypes during summertime in the central region of Chile. Austral Journal of Veterinary Sciences, 50(1), 9-14. https://doi.org/10.4067/S0719-81322018000100103
Arias, R.A., Keim, J.P., Pinto, R., & Bombal, E. (2024). Estimation of the economic impact of heat stress on the Chilean dairy regions by using two comfort thermal indices. International Journal of Biometeorology, 68, 1823-1836. https://doi.org/10.1007/s00484-024-02709-2
Arias, R.A., Mader, T.L., & Escobar, P.C. (2008). Climatic factors affecting cattle performance in dairy and beef farms. Archivos de Medicina Veterinaria, 40(1), 7-22. http://dx.doi.org/10.4067/S0301-732X2008000100002
Aubé, L., Meunier, B., & Lardy, R. (2026). Measuring shade use of dairy cattle at pasture with an on-cow light sensor: A case study. Computers and Electronics in Agriculture, 240, 111152. https://doi.org/10.1016/j.compag.2025.111152
Bang, N.N., Gaughan, J.B., Hayes, B.J., Lyons, R.E., & McNeill, D.M. (2022). Application of infrared thermal technology to assess the level of heat stress and milk yield reduction of cows in tropical smallholder dairy farms. Journal of Dairy Science, 105(10), 8454-8469. https://doi.org/10.3168/jds.2021-21343
Bar, D., Kaim, M., Flamenbaum, I., Hanochi, B., & Toaff-Rosenstein, R.L. (2019). Technical note: Accelerometer-based recording of heavy breathing in lactating and dry cows as an automated measure of heat load. Journal of Dairy Science, 102(4), 3480-3486. https://doi.org/10.3168/jds.2018-15186
Becker, C.A., Collier, R.J., & Stone, A.E. (2020). Invited review: Physiological and behavioral effects of heat stress in dairy cows. Journal of Dairy Science, 103(8), 6751-6770. https://doi.org/10.3168/jds.2019-17929
Becker, C., Aghalari, A., Marufuzzaman, M., & Stone, A. (2021). Predicting dairy cattle heat stress using machine learning techniques. Journal of Dairy Science, 104(1), 501-524. https://doi.org/10.3168/jds.2020-18653
Berman, A. (2005). Estimates of heat stress relief needs for Holstein dairy cows. Journal of Animal Science, 83(6), 1377-1384. https://doi.org/10.2527/2005.8361377x
Bewley, J.M., Einstein, M.E., Grott, M.W., & Schutz, M.M. (2008). Comparison of reticular and rectal core body temperatures in lactating dairy cows. Journal of Dairy Science, 91(12), 4661-4672. https://doi.org/10.3168/jds.2007-0835
Blackshaw, J.K., & Blackshaw, A.W. (1994). Heat stress in cattle and the effect of shade on production and behaviour: A review. Australian Journal of Experimental Agriculture, 34(2), 285-295. https://doi.org/10.1071/EA9940285
Boehmer, B.M. (2015). Ruminal temperature as a measure of body temperature of beef cows and relationship with ambient temperature. Professional Animal Scientist, 31(4), 387-393. https://doi.org/10.15232/pas.2014-01336
Bohmanova, J., Misztal, I., & Cole, J.B. (2007). Temperature-humidity indices as indicators of milk production losses due to heat stress. Journal of Dairy Science, 90(4), 1947-1956. https://doi.org/10.3168/jds.2006-513
Brito, L.F., Heringstad, B., Klaas, I.C., Schodl, K., Cabrera, V.E., Stygar, A., Iwersen, M., Haskell, M.J., Stock, K.F., Gengler, N., Bewley, J., Hostens, M., Vasseur, E., & Egger-Danner, C. (2025). Invited review: Using data from sensors and other precision farming technologies to enhance the sustainability of dairy cattle breeding programs. Journal of Dairy Science, 108(10), 10447-10474. https://doi.org/10.3168/jds.2025-26554
Bryant, J.R., Huddart, F.J., & Schütz, K.E. (2023). Development of a heat load index for grazing dairy cattle. New Zealand Journal of Agricultural Research, 66(6), 665-679. https://doi.org/10.1080/00288233.2022.2114504
Bryant, J.R., López-Villalobos, N., Pryce, J.E., Holmes, C.W. & Johnson, D.L. (2007). Quantifying the effect of thermal environment on production traits in three breeds of dairy cattle in New Zealand. New Zealand Journal of Agricultural Research, 50(3), 327-338. https://doi.org/10.1080/00288230709510301
Buffington, D.E., Collazo-Arocho, A., Canton, G.H., Pitt, D., Thatcher, W.W., & Collier, R.J. (1981). Black globe-humidity index (BGHI) as comfort equation for dairy cows. Transactions of the American Society of Agricultural Engineers, 24(3), 711-714. https://doi.org/10.13031/2013.34325
Cardoso, C.S., von Keyserlingk, M.A.G., Hötzel, M.J., Robbins, J., & Weary, D.M. (2018). Hot and bothered: Public attitudes towards heat stress and outdoor access for dairy cows. PLoS One, 13(10), e0205352. https://doi.org/10.1371/journal.pone.0205352
Cardoso, C.S., von Keyserlingk, M.A.G., Machado Filho, L.C.P., & Hotzel, M.J. (2021). Dairy heifer motivation for access to a shaded area. Animals, 11(9), 2507. https://doi.org/10.3390/ani11092507
Cartes, D., Held-Montaldo, R., & Sepúlveda-Varas, P. (2025). Behavior of transition dairy cows managed outdoors during the autumn and spring calving seasons. Animals, 15(5), 621. https://doi.org/10.3390/ani15050621
Cartes, D., Strappini, A., Matamala, F., Held-Montaldo, R., & Sepúlveda-Varas, P. (2021). Responses of outdoor housed dairy cows to shade access during the prepartum period under temperate summer conditions. Animals, 11(10), 2911. https://doi.org/10.3390/ani11102911
Chen, L., Shen, Y., Wang, C., Ding, L., Zhao, F., Wang, M., Fu, J., & Wang, H. (2019). Megasphaera elsdenii lactate degradation pattern shifts in rumen acidosis models. Frontiers in Microbiology, 10, 162. https://doi.org/10.3389/fmicb.2019.00162
Chen, L., Thorup, V.M., Kudahl, A.B., & Østergaard, S. (2024). Effects of heat stress on feed intake, milk yield, milk composition, and feed efficiency in dairy cows: A meta-analysis. Journal of Dairy Science, 107(5), 3207-3218. https://doi.org/10.3168/jds.2023-24059
Chen, S., Luo, S., & Yan, C. (2022). Gut microbiota implications for health and welfare in farm animals: A review. Animals, 12(1), 93. https://doi.org/10.3390/ani12010093
Chen, S., Wang, J., Peng, D., Li, G., Chen, J., & Gu, X. (2018). Exposure to heat-stress environment affects the physiology, circulation levels of cytokines, and microbiome in dairy cows. Scientific Reports, 8, 14606. https://doi.org/10.1038/s41598-018-32886-1
Chick, S., Ataei, Kachouei, M., Knowlton, K., & Ali, M.A. (2024). Functionalized Graphene-Based Biosensors for Early Detection of Subclinical Ketosis in Dairy Cows. ACS Applied Materials & Interfaces, 16(39), 51932-51943. https://doi.org/10.1021/acsami.4c07715
Chung, H., Li, J., Kim, Y., Van Os, J.M.C, Brounts, S.H., & Choi, C.Y. (2020). Using implantable biosensors and wearable scanners to monitor dairy cattle’s core body temperature in real time. Computers and Electronics in Agriculture, 174, 105453. https://doi.org/10.1016/j.compag.2020.105453
de Sousa, K.T., Deniz, M., Moro, F.M., Cordova, I., Martinez, M. & Dittrich, J.R. (2021). Developing of a model to predict lying behavior of dairy cows on silvopastoral system during the winter season. International Journal of Biometeorology, 65, 1781-1786. https://doi.org/10.1007/s00484-021-02121-0
Deniz, M., de Sousa, K.T., Moro, M.F., do Vale, M.M., Dittrich, J.R., Machado Filho, L.C.P., & Hötzel, M.J. (2021). Social hierarchy influences dairy cows’ use of shade in a silvopastoral system under intensive rotational grazing. Applied Animal Behaviour Science, 244, 105467. https://doi.org/10.1016/j.applanim.2021.105467
Deniz, M., Schmitt Filho, A.L., Hötzel, M.J., de Sousa, K.T., & Machado Filho, L.C.P. (2020). Microclimate and pasture area preferences by dairy cows under high biodiversity silvopastoral system. International Journal of Biometeorology, 64, 1877-1887. https://doi.org/10.1007/s00484-020-01975-0
Deniz, M., Sena, A.R., De Sousa, K.T., Vieira, F.M.C., de Souza, E.R., Hötzel, M.J., & Dittrich, J.R. (2025). Herd dominance influences dairy cows' use of heat abatement resources in a silvopastoral system. Animals, 15(12), 1791. https://doi.org/10.3390/ani15121791
Diniso, Y.S., Zhou, L., & Jaja, I.F. (2022). Dairy farmers’ knowledge and perception of climate change in the Eastern Cape province, South Africa. International Journal of Climate Change Strategies and Management, 14(2), 168-179. https://doi.org/10.1108/IJCCSM-11-2020-0120
Džermeikaitė, K., Krištolaitytė, J., Malašauskienė, D., Arlauskaitė, S., Girdauskaitė, A., & Antanaitis, R. (2025). The impact of heat stress on dairy cattle: Effects on milk quality, rumination behaviour, and reticulorumen pH response using machine learning models. Biosensors, 15(9), 608. https://doi.org/10.3390/bios15090608
Feng, L., Zhang, Y., Liu, W., Du, D., Jiang, W., Wang, Z., Li, N., & Hu, Z. (2023). Altered rumen microbiome and correlations of the metabolome in heat-stressed dairy cows at different growth stages. Microbiology Spectrum, 11(6), e0331223. https://doi.org/10.1128/spectrum.03312-23
Foroushani, S., & Amon, T. (2022). Thermodynamic assessment of heat stress in dairy cattle: Lessons from human biometeorology. International Journal of Biometeorology, 66, 1811-1827. https://doi.org/10.1007/s00484-022-02321-2
Furukawa, E., Ozawa, T., Higaki, S., Suda, T., Sasaki, Y., Murayama, K., Noguchi, M., & Yoshioka, K. (2024). Changes in skin temperature and behaviors of preweaning Holstein calves in a hot environment monitored by a multimodal tail-attached device. JDS Communications, 5(4), 332-337. https://doi.org/10.3168/jdsc.2023-0515.
Gaughan, J.B., & Lees, J.C. (2010). Categorising heat load on dairy cows. 28th Biennial Conference of the Australian Society of Animal Production, Armidale, NSW, Australia. Australian Society of Animal Production, Brisbane, Queensland, Australia. https://espace.library.uq.edu.au/view/UQ:238138
Gaughan, J.B., Mader, T.L., Holt, S.M., & Lisle, A. (2008). A new heat load index for feedlot cattle. Journal of Animal Science, 86(1), 226-234. https://doi.org/10.2527/jas.2007-0305
Giro, A., Pezzopane, J.R.M., Barioni Junior, W., Pedroso, A.F., Lemes, A.P., Botta, D., Romanello, N., Barreto, A.N., & Garcia, A.R. (2019). Behaviour and body surface temperature of beef cattle in integrated crop–livestock systems with or without tree shading. Science of the Total Environment, 684, 587-596. https://doi.org/10.1016/j.scitotenv.2019.05.377
Gunn, K.M., Holly, M.A., Veith, T.L., Buda, A.R., Prasad, R., & Rotz, C.A. (2019). Projected heat stress challenges and abatement opportunities for U.S. milk production. PLoS One 14(3), e0214665. https://doi.org/10.1371/journal.pone.0214665
He, G., Zhang, B., Yi, K., Chen, T., Shen, C., Cao, M., Wang, N., Zong, J., Wang, Y., Liu, K., Chang, F., Chen, X., Chen, L., Luo, Y., Meng, Y., Li, C., & Zhou, X. (2024). Heat stress-induced dysbiosis of the gut microbiota impairs spermatogenesis by regulating secondary bile acid metabolism in the gut. Science of the Total Environment, 937, 173305. https://doi.org/10.1016/j.scitotenv.2024.173305
Hendriks, J., Mills, K.E., Sirovica, L.V., Sundermann, L., Bolton, S.E., & von Keyserlingk, M.A.G. (2022). Public perceptions of potential adaptations for mitigating heat stress on Australian dairy farms. Journal of Dairy Science, 105(7), 5893-5908. https://doi.org/10.3168/jds.2022-21813
Hendriks, S.J., Edwards, J.P., Shirley, A.K., Clark, C.E.F., Schütz, K.E., Verhoek, K.J., & Jago, J.G. (2025). Heat stress amelioration for pasture-based dairy cattle: Challenges and opportunities. Animal Frontiers, 15(2), 32-43. https://doi.org/10.1093/af/vfae043
Hendriks, S.J., Phyn, C.V.C., Turner, S.A., Mueller, K.R., Kuhn-Sherlock, B., Donaghy, D.J., Huzzey, J.M., & Roche, J.R. (2019). Effect of weather on activity and lying behaviour in clinically healthy grazing dairy cows during the transition period. Animal Production Science 60(1), 148. https://doi.org/10.1071/AN18569
Herbut, P., Angrecka, S., & Walczak, J. (2018). Environmental parameters to assessing heat stress in dairy cattle: A review. International Journal of Biometeorology, 62, 2089-2097. https://doi.org/10.1007/s00484-018-1629-9
Hill, T.M., Bateman, H.G. 2nd., Suarez-Mena, F.X., Dennis, T.S., & Schlotterbeck, R.L. (2016). Short communication: Changes in body temperature of calves up to 2 months of age as affected by time of day, age, and ambient temperature. Journal of Dairy Science, 99(11), 8867-8870. https://doi.org/10.3168/jds.2016-10994.
Hitchman, S., Zobel, G., Schütz, K.E., Jago, J.G., Reed, C., Hay, E., Thomas, C., Edwards, J.P., & Verhoek, K.J. (2024). Updated method of estimating heat load for grazing dairy cattle. New Zealand Journal of Agricultural Research, 68(6), 1611-1631. https://doi.org/10.1080/00288233.2024.2396970
Hristov, H. (2025). Using infrared thermography to study the impact of dangerous heat stress on thigh and udder temperature in dairy cows. Engineering Proceedings 104(1), 94. https://doi.org/10.3390/engproc2025104094
Idris, M., Uddin, J., Sullivan, M., McNeill, D, & Phillips, C. (2021). Non-Invasive Physiological Indicators of Heat Stress in Cattle. Animals, 11(1), 71. https://doi.org/10.3390/ani11010071
International Dairy Federation. (2025). Managing heat stress in dairy cattle. Bulletin of the IDF No. 534/2025. https://doi.org/10.56169/NFGC1866
Islam, M.A., Lomax, S., Doughty, A.K., Islam, M.R., & Clark, C.E.F. (2020). Automated monitoring of panting for feedlot cattle: Sensor system accuracy and individual variability. Animals 10(9), 1518. https://doi.org/10.3390/ani10091518
Islam, M.A., Lomax, S., Doughty, A.K., Islam, M.R., Jay, O., Thomson, P., & Clark, C.E.F. (2021). Automated monitoring of cattle heat stress and its mitigation. Frontiers in Animal Science 2, 737213. https://doi.org/10.3389/fanim.2021.737213
Jara, I.E., Keim, J.P., & Arias, R.A. (2016). Behaviour, tympanic temperature and performance of dairy cows during summer season in southern Chile. Archivos de Medicina Veterinaria 48(1), 113-118. http://dx.doi.org/10.4067/S0301-732X2016000100014
Ji, B., Banhazi, T.M., Perano, K.M., Ghahramani, A., Bowtell, L., Wang, C., & Li, B. (2020). A review of measuring, assessing and mitigating heat stress in dairy cattle. Biosystems Engineering 199, 4-26. https://doi.org/10.1016/j.biosystemseng.2020.07.009
Kappes, R., Knob, D.A., Scheid, A.L., Barreta, B.E., Perazzoli, L., Mendes, B.B., Alessio, D.R.M., & Neto, A.T. (2022). Rumination time, activity index, and productive performance of Holstein and crossbred Holstein × Jersey cows exposed to different temperature-humidity indexes. International Journal of Biometeorology 66, 791-801. https://doi.org/10.1007/s00484-021-02237-3
Kendall, P.E., Nielsen, P.P., Webster, J.R., Verkerk, G.A., Littlejohn, R.P., & Matthews, L.R. (2006). The effects of providing shade to lactating dairy cows in a temperate climate. Livestock Science 103(1-2), 148–157. https://doi.org/10.1016/j.livsci.2006.02.004
Kim, D.H., Kim, M.H., Kim, S.B., Son, J.K., Lee, J.H., Joo, S.S., Gu, B.H., Park, T., Park, B.Y., & Kim, E.T. (2020). Differential dynamics of the ruminal microbiome of Jersey cows in a heat stress environment. Animals 10(7), 1127. https://doi.org/10.3390/ani10071127
Koch, F., Albrecht, D., Gors, S., & Kuhla, B. (2021). Jejunal mucosa proteomics unravel metabolic adaptive processes to mild chronic heat stress in dairy cows. Scientific Reports 11, 12484. https://doi.org/10.1038/s41598-021-92053-x
Koch, F., Reyer, H., Görs, S., Hansen, C., Wimmers, K., & Kuhla, B. (2024). Heat stress and feeding effects on the mucosa-associated and digesta microbiome and their relationship to plasma and digesta fluid metabolites in the jejunum of dairy cows. Journal of Dairy Science 107(7), 5162-5177. https://doi.org/10.3168/jds.2023-24242
Koch, F., Thom, U., Albrecht, E., Weikard, R., Nolte, W., Kuhla, B., & Kuehn, C. (2019). Heat stress directly impairs gut integrity and recruits distinct immune cell populations into the bovine intestine. Proceedings of the National Academy of Sciences of the United States of America, 116(21), 10333-10338. https://doi.org/10.1073/pnas.1820130116
Koltes, J.E., Koltes, D.A., Mote, B.E., Tucker, J., & Hubbell, D.S. (2018). Automated collection of heat stress data in livestock: New technologies and opportunities. Translational Animal Science, 2(3), 319-323. https://doi.org/10.1093/tas/txy061
Kökten, T.F., Hansmannel, N.C., Ndiaye, A.C., Heba, D., Quilliot, N., Dreumont, D., & Peyrin-Biroulet, L. (2021). Calorie restriction as a new treatment of inflammatory diseases. Advances in Nutrition 12, 1558-1570. https://doi.org/10.1093/advances/nmaa179
Kraimi, N., Dawkins, M., Gebhardt-Henrich, S.G., Velge, P., Rychlik, I., Volf, J., Creach, P., Smith, A., Colles, F., & Leterrier, C. (2019). Influence of the microbiota-gut-brain axis on behaviour and welfare in farm animals: A review. Physiology & Behavior, 210, 112658. https://doi.org/10.1016/j.physbeh.2019.112658
Lamp, O., Derno, M., Otten, W., Mielenz, M., Nürnberg, G., & Kuhla, B. (2015). Metabolic heat stress adaption in transition cows: Differences in macronutrient oxidation between late-gestating and early-lactating German Holstein dairy cows. PLoS One 10(5), e0125264. https://doi.org/10.1371/journal.pone.0125264
Lane, D., Murdock, E., Genskow, K., Rumery Betz, C., & Chatrchyan, A. (2019). Climate change and dairy in New York and Wisconsin: Risk perceptions, vulnerability, and adaptation among farmers and advisors. Sustainability, 11(13), 33599. https://doi.org/10.3390/su11133599
Lees, J.C., Lees, A.M., & Gaughan, J.B. (2018a). Developing a heat load index for lactating dairy cows. Animal Production Science, 58(8), 1387-1391. https://doi.org/10.1071/AN17776
Lees, J.C., Lees, A.M., & Gaughan, J.B. (2022). The influence of shade availability on the effectiveness of the Dairy Heat Load Index (DHLI) to predict lactating cow behavior, physiology, and production traits. International Journal of Biometeorology, 66, 289-299. https://doi.org/10.1007/s00484-021-02186-x
Lees, A.M., Lees, J., Lisle, A., Sullivan, M., & Gaughan, J. (2018b). Effect of heat stress on rumen temperature of three breeds of cattle. Interna¬tional Journal of Biometeorology, 62, 207-215. https://doi.org/10.1007/s00484-017-1442-x
Lees, A.M., Sejian, V., Wallage, A.L., Steel, C.C., Mader, T.L., Lees, J.C., & Gaughan, J.B. (2019). The impact of heat load on cattle. Animals 9(6), 322. https://doi.org/10.3390/ani9060322
Leliveld, L.M.C., Lovarelli, D., & Provolo, G. (2025). Dairy cow behaviour and physical activity as indicators of heat stress. Italian Journal of Animal Science, 24(1), 772–783. https://doi.org/10.1080/1828051X.2025.2471545
Li, Z., Fan, Y., Bai, H., Zhang, J., Mao, S., & Jin, W. (2023). Live yeast supplementation altered the bacterial community's composition and function in rumen and hindgut and alleviated the detrimental effects of heat stress on dairy cows. Journal of Animal Science, 101, skac410. https://doi.org/10.1093/jas/skac410
Li, M., Wang, Z., Ma, Z., Wang, Y., Jia, H., Zhang, L., Chen, P., Mao, Y., & Yang, Z. (2025). Metagenomic analysis reveals microbial drivers of heat resistance in dairy cattle. Animal Microbiome, 7, 35. https://doi.org/10.1186/s42523-025-00399-8
Mader, T.L., Davis, M.S., & Brown-Brandl, T. (2006). Environmental factors influencing heat stress in feedlot cattle. Journal of Animal Science, 84(3), 712-719. https://doi.org/10.2527/2006.843712x
Mader, T.L., Johnson, L.J, & Gaughan, J.B. (2010). A comprehensive index for assessing environmental stress in animals. Journal of Animal Science, 88(6), 2153-2165. https://doi.org/10.2527/jas.2009-2586
Maia, G.G., Siqueira, L.C., Tomich, C.O.P., Camargo, T.R., Rodrigues, L.S.A., Menezes, J.P.P., Gonçalves, R.A., Oliveira Nogueira, R., Garcia, L.A., & Pereira, L.G.R. (2020). Effects of heat stress on rumination activity in dairy cows. Livestock Science, 239, 104092. https://doi.org/10.1016/j.livsci.2020.104092
McDonald, K., Goldhawk, C., & Proudfoot, K.L. (2020). Social rank influences drinking behaviour of dairy cows under heat stress. Applied Animal Behaviour Science, 224, 104947. https://doi.org/10.1016/j.applanim.2020.104947
Müschner-Siemens, T., Hoffmann, G., Ammon, C., & Amon, T. (2020). Daily rumination time of lactating dairy cows under heat stress conditions. Journal of Thermal Biology, 88, 102484. https://doi.org/10.1016/j.jtherbio.2019.102484
Nascimento, D.R., Azevedo, V.A.N., Ribeiro, R.P., Ximenes, G.O., Silva, A.A., Barbalho, E.C., Barrozo, L.G., Chaves, S.C., Castro, M.S.M., Marcelino, E.C., Vaz da Silva, L.R.C., Batista, A.M., & Silva, J.R.V. (2025). Reproductive challenges in ruminants under heat stress: A review of follicular, oocyte, and embryonic responses. Animals, 15(15), 2296. https://doi.org/10.3390/ani15152296
National Research Council. (1971). A guide to environmental research on animals. National Academy of Sciences. https://www.nationalacademies.org/read/20608
Nielsen, P.P., & Wredle, E. (2023). How Does the Provision of Shade during Grazing Affect Heat Stress Experienced by Dairy Cows in Sweden? Animals, 13(24), 3823. https://doi.org/10.3390/ani13243823
Osei-Amponsah, R., Dunshea, F.R., Leury, B.J., Cheng, L., Cullen, B., Joy, A., & Chauhan, S.S. (2020). Heat stress impacts on lactating cows grazing Australian summer pastures on an automatic robotic dairy. Animals, 10(5), 869. https://doi.org/10.3390/ani10050869
Pathirana, I.N., & Garcia, S.C. (2022). Detection of heat-shock protein 70 in cow’s milk using ELISA. Animal Production Science, 62(12), 1014–1019. https://doi.org/10.1071/AN21506
Petersen, C., & Round, J.L. (2014). How changes in microbiota structure influence health. Cellular Microbiology, 16(7), 1024-1033. https://doi.org/10.1111/cmi.12308
Pinto, S., Hoffmann, G., Ammon, C., & Amon, T. (2020). Critical THI thresholds based on physiological parameters of lactating dairy cows. Journal of Thermal Biology, 88, 102523. https://doi.org/10.1016/j.jtherbio.2020.102523
Polsky, L., & von Keyserlingk, M.A.G. (2017). Effects of heat stress on dairy cattle welfare. Journal of Dairy Science, 100(11), 8645-8657. https://doi.org/10.3168/jds.2017-12651
Pontiggia, A., Holinger, M., Münger, A., Ammer, S., Dohme-Meier, F., & Keil, N.M. (2025). Mitigating heat stress in full-time grazing dairy cows in temperate climates: The impact of indoor housing during the hottest time of day. Journal of Dairy Science, 29, 100488. https://doi.org/10.1016/j.vas.2025.100488
Razzaghi, A., Ghaffari, M.H., & Rico, D.E. (2023). The impact of environmental and nutritional stresses on milk fat synthesis in dairy cows. Domestic Animal Endocrinology, 83 106784. https://doi.org/10.1016/j.domaniend.2022.106784
Rizzatti, G., Lopetuso, L.R., Gibiino, G., Binda, C., & Gasbarrini, A. (2017). Proteobacteria: A common factor in human diseases. BioMed Research International, 2017, 9351507. https://doi.org/10.1155/2017/9351507
Schütz, K.E., Cox, N.R., Cave, V.M., Huddart, F.J., & Tucker, C.B. (2023). Effects of changing milking and feeding times on the behaviour, body temperature, respiration rate and milk production of dairy cows on pasture. Applied Animal Behaviour Science, 261, 105895. https://doi.org/10.1016/j.applanim.2023.105895
Setser, M.M.W., Cantor, M.C., & Costa, J.H.C. (2020). A comprehensive evaluation of microchips to measure temperature in dairy calves. Journal of Dairy Science, 103(10), 9290-9300. https://doi.org/10.3168/jds.2019-17999
Shephard, R.W., & Maloney, S.K. (2023). A review of thermal stress in cattle. Australian Veterinary Journal, 101(11), 417-429. https://doi.org/10.1111/avj.13275
Stygar, A.H., Gómez, Y., Berteselli, G.V., Dalla Costa, E., Canali, E., Niemi, J.K., Llonch, P., & Pastell, M. (2021). A systematic review on commercially available and validated sensor technologies for welfare assessment of dairy cattle. Frontiers in Veterinary Science, 8, 634338. https://doi.org/10.3389/fvets.2021.634338
Tamminen, L., Båge, R., Åkerlind, M., & Olmos Antillón, G. (2024). Farmers´ sense of the biological impact of extreme heat and seasonality on Swedish high-yielding dairy cows – A mixed methods approach. Preventive Veterinary Medicine, 224, 106131. https://doi.org/10.1016/j.prevetmed.2024.106131
Thom, E.C. (1959). The discomfort index. Weatherwise, 12, 57-59. https://doi.org/10.1080/00431672.1959.9926960
Toledo, I.M., Dahl, G.E., & de Vries, A. (2022). Dairy cattle management and housing for warm environments. Livestock Science, 255, 104802. https://doi.org/10.1016/j.livsci.2021.104802
Tresoldi, G., Schütz, K.E., & Tucker, C.B. (2016). Assessing heat load in drylot dairy cattle: Refining on-farm sampling methodology. Journal of Dairy Science, 99(11), 8970-8980. https://doi.org/10.3168/jds.2016-11353
Tresoldi, G., Schütz, K.E., & Tucker, C.B. (2020). Sampling strategy and measurement device affect vaginal temperature outcomes in lactat¬ing dairy cattle. Journal of Dairy Science, 103(6), 5414-5421. https://doi.org/10.3168/jds.2019-16667
Tucker, C.B., Jensen, M.B., de Passillé, A.M., & Hänninen, L. (2021). Invited review: Lying time and the welfare of dairy cows. Journal of Dairy Science, 104(1), 20-46. https://doi.org/10.3168/jds.2019-18074
Tullo, E., Mattachini, G., Riva, E., Finzi, A., Provolo, G., & Guarino, M. (2019). Effects of Climatic Conditions on the Lying Behavior of a Group of Primiparous Dairy Cows. Animals, 9(11), 869. https://doi.org/10.3390/ani9110869
Um, K.H., Cho, S.R., Kang, S.S., Kim, U.H., Won, J.I., Jin, S., Park, M., Moon, S.J., Jang, G.S., Shokrollahi, B., Baek, Y.C., & Jang, S.S. (2024). Effects of heat stress on the physiological responses and vaginal microbiome of Hanwoo cows. South African Journal of Animal Science, 54(6), 708-722. https://doi.org/10.4314/sajas.v54i6.05
van Erp-van der Kooij, E., Leenders, N.L.G., & Roelofs, J. (2024). Automatic monitoring of body temperature in dairy cows using implanted sensors. In: Berckmans D, Tassinari P, Torreggiani D, eds. Proceedings 11th European Conference on Precision Livestock Farming (ECPLF 2024), European Association for Precision Livestock Farming, p. 836-843. https://research.wur.nl/en/publications/automatic-monitoring-of-body-temperature-in-dairy-cows-using-impl/
Verhoek, K.J., Reed, C., McGowan, J., Cuthbert, S., & Jago, J.G. (2026). Understanding Farmer Perspectives of Cow Heat Stress in the Waikato and Canterbury Regions of New Zealand. New Zealand Journal of Agricultural Research, 69(1), e70024. https://doi.org/10.1002/jag2.70024
Vieira, F. M., Soares, A. A., Herbut, P., Vismara, E. D., Godyń, D., Dos Santos, A. C., Lambertes, T. D., & Caetano, W. F. (2021). Spatio-Thermal Variability and Behaviour as Bio-Thermal Indicators of Heat Stress in Dairy Cows in a Compost Barn: A Case Study. Animals, 11(5), 1197. https://doi.org/10.3390/ani11051197
Vitali, A., Felici, A., Lees, A.M., Giacinti, G., Maresca, C., Bernabucci, U., Gaughan, J.B., Nardone, A., & Lacetera, N. (2020). Heat load increases the risk of clinical mastitis in dairy cattle. Journal of Dairy Science, 103(9), 8378-8387. https://doi.org/10.3168/jds.2019-17748
Wang, Z., Liu, L., Pang, F., Zheng, Z., Teng, Z., Miao, T., Fu, T., Rushdi, H.E., Yang, L., Gao, T., Lin, F., & Liu, S. (2022b). Novel insights into heat tolerance using metabolomic and high-throughput sequencing analysis in dairy cows rumen fluid. Animal, 16(3), 100478. https://doi.org/10.1016/j.animal.2022.100478
Wang, Z., Niu, K., Rushdi, H.E., Zhang, M., Fu, T., Gao, T., Yang, L., Liu, S., & Lin, F. (2022a). Heat stress induces shifts in the rumen bacteria and metabolome of buffalo. Animals, 12(10), 1300. https://doi.org/10.3390/ani12101300
Wang, X., Wang, Y., Feng, M., Li, J., Liu, Z., Fu, L., Zhang, N., Zhang, H., & Qin, J. (2025). Herbal formula alleviates heat stress by improving physiological and biochemical attributes and modulating the rumen microbiome in dairy cows. Frontiers in Veterinary Science, 12, 1558856. https://doi.org/10.3389/fvets.2025.1558856
Wankar, A.K., Rindhe, S.N., & Doijad, N.S. (2021). Heat stress in dairy animals and current milk production trends, economics, and future perspectives: The global scenario. Tropical Animal Health and Production, 53, 70. https://doi.org/10.1007/s11250-020-02541-x
Welch, C.B., Ryman, V.E., Pringle, T.D., & Lourenco, J.M. (2022). Utilizing the gastrointestinal microbiota to modulate cattle health through the microbiome-gut-organ axes. Microorganisms, 10(7), 1391. https://doi.org/10.3390/microorganisms10071391
Westin, R., Vaughan, A., de Passillé, A.M., DeVries, T.J., Pajor, E.A., Pellerin, D., Siegford, J.M., Vasseur, E., & Rushen, J. (2016). Lying times of lactating cows on dairy farms with automatic milking systems and the relation to lameness, leg lesions, and body condition score. Journal of Dairy Science, 99(1), 551–562. https://doi.org/10.3168/jds.2015-9737
Wickware, C.L., Johnson, T.A., & Koziol, J.H. (2020). Composition and diversity of the preputial microbiota in healthy bulls. Theriogenology, 145, 231-237. https://doi.org/10.1016/j.theriogenology.2019.11.002
Woodward, S.J.R., Beukes, P.C., Edwards, J.P., Verhoek, K.J., Jago, J.G. & Zammit, C. (2024a). Prediction of regional heat stress risk for grazing dairy cows in a changing climate. agriRxiv [Preprint] 20240429911:1. https://doi.org/10.31220/agriRxiv.2024.00280
Woodward, S.J.R., Edwards, J.P., Verhoek, K.J., & Jago, J.G. (2024b). Identifying and predicting heat stress events for grazing dairy cows using rumen temperature boluses. JDS Communications, 5(5), 431-435. https://doi.org/10.3168/jdsc.2023-0482
Woodward, S.J.R., Farrell, L.J., Burke, C.R., & Edwards, J.P. (2025). Modeling shade use of grazing dairy cows using sensor-derived data and machine learning. Journal of Dairy Science, 108(10), 11151-11163. https://doi.org/10.3168/jds.2025-26904
Yan, G., Li, H., & Shi, Z. (2021). Evaluation of thermal indices as the indicators of heat stress in dairy cows in a temperate climate. Animals, 11(8), 2459. https://doi.org/10.3390/ani11082459
Zeineldin, M., Barakat, R., Elolimy, A., Salem, A.Z.M., Elghandour, M.M.Y., & Monroy, J.C. (2018). Synergetic action between the rumen microbiota and bovine health. Microbial Pathogenesis, 124, 106-115. https://doi.org/10.1016/j.micpath.2018.08.038
Zhao, S., Min, L., Zheng, N., & Wang, J. (2019). Effect of heat stress on bacterial composition and metabolism in the rumen of lactating dairy cows. Animals, 9(11), 925. https://doi.org/10.3390/ani9110925
Zhuang, X., Chen, Z., Sun, X., Li, F., Luo, J., Chen, T., Xi, Q., Zhang, Y., & Sun, J. (2021). Fermentation quality of herbal tea residue and its application in fattening cattle under heat stress. BMC Veterinary Research, 17, 348. https://doi.org/10.1186/s12917-021-03061-y