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: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Veterinary World
2025-07-01
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| Series: | Veterinary World |
| Subjects: | |
| Online Access: | https://www.veterinaryworld.org/Vol.18/July-2025/22.pdf |
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| Summary: | 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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| ISSN: | 0972-8988 2231-0916 |