Thermal microclimate assessment in dairy cow milking parlors: Seasonal variations in temperature-humidity index and implications for heat stress

Background and Aim: Rising global temperatures and increasing humidity levels are intensifying the risk of heat stress (HS) in high-yielding dairy cattle. The temperature–humidity index (THI) is a standard metric for evaluating thermal stress in livestock. This study aimed to assess seasonal and diu...

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Main Authors: Dimo Dimov, Toncho Penev, Ivaylo Marinov
Format: Article
Language:English
Published: Veterinary World 2025-07-01
Series:Veterinary World
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Online Access:https://www.veterinaryworld.org/Vol.18/July-2025/22.pdf
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author Dimo Dimov
Toncho Penev
Ivaylo Marinov
author_facet Dimo Dimov
Toncho Penev
Ivaylo Marinov
author_sort Dimo Dimov
collection DOAJ
description Background and Aim: Rising global temperatures and increasing humidity levels are intensifying the risk of heat stress (HS) in high-yielding dairy cattle. The temperature–humidity index (THI) is a standard metric for evaluating thermal stress in livestock. This study aimed to assess seasonal and diurnal variations in temperature, relative humidity, and THI within a milking parlor and determine their compliance with established thermal comfort thresholds for dairy cows. Materials and Methods: The study was conducted in a glass-roofed, windowless milking parlor housing 400 Holstein–Friesian cows in Bulgaria. Microclimatic parameters (temperature, relative humidity, and THI) were measured during three daily milking sessions (morning, noon, and evening) at 3 time points (start, middle, and end) over a 12-month period. Measurements were taken inside the parlor and 10 m outside. Statistical analysis involved one-way analysis of variance and post hoc tests using STATISTICA version 10. Results: Summer and spring exhibited the highest mean and peak temperatures (up to 31.4 °C), while winter showed the highest relative humidity (82.39%). THI values peaked in summer, reaching levels classified as “danger” for dairy cows. Morning milking generally recorded lower temperatures and THI. Seasonal variation significantly influenced all microclimatic indicators (p < 0.001), while milking sequence significantly affected temperature and THI (p < 0.05). Conclusion: In-parlor thermal conditions, especially during summer, exceeded comfort thresholds and posed a risk for HS. The study underscores the urgent need to revise livestock housing regulations to include THI-specific standards for milking parlors. Incorporating real-time microclimatic monitoring can enhance animal welfare and productivity in dairy systems.
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spelling doaj-art-4c581bf1797442a0a45bcd1ef3b38dfb2025-08-20T03:13:45ZengVeterinary WorldVeterinary World0972-89882231-09162025-07-011872024203010.14202/vetworld.2025.2024-2030Thermal microclimate assessment in dairy cow milking parlors: Seasonal variations in temperature-humidity index and implications for heat stressDimo Dimov0https://orcid.org/0000-0001-8649-9508Toncho Penev1https://orcid.org/0000-0001-6085-5244Ivaylo Marinov2https://orcid.org/0000-0002-3896-8741Department of Ecology and Animal Hygiene, Faculty of Agriculture, Trakia University, 6000, Bulgaria.Department of Ecology and Animal Hygiene, Faculty of Agriculture, Trakia University, 6000, Bulgaria.Department of Animal Husbandry, Ruminant Animals and Animal Products Technologies, Faculty of Agriculture, Trakia University, 6000, Bulgaria.Background and Aim: Rising global temperatures and increasing humidity levels are intensifying the risk of heat stress (HS) in high-yielding dairy cattle. The temperature–humidity index (THI) is a standard metric for evaluating thermal stress in livestock. This study aimed to assess seasonal and diurnal variations in temperature, relative humidity, and THI within a milking parlor and determine their compliance with established thermal comfort thresholds for dairy cows. Materials and Methods: The study was conducted in a glass-roofed, windowless milking parlor housing 400 Holstein–Friesian cows in Bulgaria. Microclimatic parameters (temperature, relative humidity, and THI) were measured during three daily milking sessions (morning, noon, and evening) at 3 time points (start, middle, and end) over a 12-month period. Measurements were taken inside the parlor and 10 m outside. Statistical analysis involved one-way analysis of variance and post hoc tests using STATISTICA version 10. Results: Summer and spring exhibited the highest mean and peak temperatures (up to 31.4 °C), while winter showed the highest relative humidity (82.39%). THI values peaked in summer, reaching levels classified as “danger” for dairy cows. Morning milking generally recorded lower temperatures and THI. Seasonal variation significantly influenced all microclimatic indicators (p < 0.001), while milking sequence significantly affected temperature and THI (p < 0.05). Conclusion: In-parlor thermal conditions, especially during summer, exceeded comfort thresholds and posed a risk for HS. The study underscores the urgent need to revise livestock housing regulations to include THI-specific standards for milking parlors. Incorporating real-time microclimatic monitoring can enhance animal welfare and productivity in dairy systems.https://www.veterinaryworld.org/Vol.18/July-2025/22.pdfdairy cowsheat stressmicroclimatemilking parlorseasonal variationtemperature–humidity indexthermal comfort
spellingShingle Dimo Dimov
Toncho Penev
Ivaylo Marinov
Thermal microclimate assessment in dairy cow milking parlors: Seasonal variations in temperature-humidity index and implications for heat stress
Veterinary World
dairy cows
heat stress
microclimate
milking parlor
seasonal variation
temperature–humidity index
thermal comfort
title Thermal microclimate assessment in dairy cow milking parlors: Seasonal variations in temperature-humidity index and implications for heat stress
title_full Thermal microclimate assessment in dairy cow milking parlors: Seasonal variations in temperature-humidity index and implications for heat stress
title_fullStr Thermal microclimate assessment in dairy cow milking parlors: Seasonal variations in temperature-humidity index and implications for heat stress
title_full_unstemmed Thermal microclimate assessment in dairy cow milking parlors: Seasonal variations in temperature-humidity index and implications for heat stress
title_short Thermal microclimate assessment in dairy cow milking parlors: Seasonal variations in temperature-humidity index and implications for heat stress
title_sort thermal microclimate assessment in dairy cow milking parlors seasonal variations in temperature humidity index and implications for heat stress
topic dairy cows
heat stress
microclimate
milking parlor
seasonal variation
temperature–humidity index
thermal comfort
url https://www.veterinaryworld.org/Vol.18/July-2025/22.pdf
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AT tonchopenev thermalmicroclimateassessmentindairycowmilkingparlorsseasonalvariationsintemperaturehumidityindexandimplicationsforheatstress
AT ivaylomarinov thermalmicroclimateassessmentindairycowmilkingparlorsseasonalvariationsintemperaturehumidityindexandimplicationsforheatstress