Estimating losses in milk production by heat stress and environmental impacts of greenhouse gas emissions in Korean dairy farms

Geun-woo Park1, Mohammad Ataallahi1, Seon Yong Ham2, Se Jong Oh3, Ki-Youn Kim4,*, Kyu-Hyun Park1,**
Author Information & Copyright
1College of Animal Life Sciences, Kangwon National University, Chuncheon 24341, Korea.
2Business Support Team, Korea Dairy Committee, Sejong 30121, Korea.
3College of Animal Life Sciences, Jeonnam National University, Gwangju 61186, Korea.
4Dept of Safety Engineering, Seoul National University of Science & Technology, Seoul 01811, Korea.
**Corresponding Author: Ki Youn Kim, Dept of Safety Engineering, Seoul National University of Science & Technology, Seoul 01811, Korea, Republic of. Phone: +82-2-970-6376. E-mail:
**Corresponding Author: Kyu Hyun Park, College of Animal Life Sciences, Kangwon National University, Chuncheon 24341, Korea, Republic of. Phone: +82-33-250-8621. E-mail:

© Copyright 2021 Korean Society of Animal Science and Technology. This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.


Meteorological disasters caused by climate change like heat, cold waves, and unusually long rainy seasons affect the milk productivity of cows. Studies have been conducted on how milk productivity and milk compositions change due to heat stress (HS). However, the estimation of losses in milk production due to HS and hereby environmental impacts of greenhouse gas (GHG) emissions are yet to be evaluated in Korean dairy farms. Dairy milk production and milk compositions data from March to October 2018, provided by the Korea Dairy Committee (KDC), were used to compare regional milk production with the temperature-humidity index (THI). Raw data for the daily temperature and relative humidity in 2018 were obtained from the Korea Meteorological Administration (KMA). This data was used to calculate the THI and the difference between the maximum and minimum temperature changing rate, as the average daily temperature range, to show the extent to which the temperature gap can affect milk productivity. The amount of milk was calculated based on the price of 926 won/kg from KDC. The results showed that the average milk production rate was the highest within the THI range 60-73 in three regions in May: Chulwon (northern region), Hwasung (central region), and Gunwi (southern region). The average milk production decreased by 4.96±1.48% in northern region, 7.12±2.36% in central region, and 7.94±2.57% in southern region from June to August, which had a THI range of 73 or more, when compared to May. Based on the results, the level of THI should be maintained like May. If so, the farmers can earn a profit of 9,128,730 won/farm in northern region, 9,967,880 won/farm in central region, and 12,245,300 won/farm in southern region. Additionally, the average number of cows raised can be reduced by 2.41±0.35 heads/farm, thereby reducing GHG emissions by 29.61±4.36 kg CO₂eq/day on average. Overall, the conclusion suggests that maintaining environmental conditions in the summer that are similar to those in May is necessary. This knowledge can be used for basic research to persuade farmers to change farm facilities to increase the economic benefits and improve animal welfare.

Keywords: Climate change; Dairy milk productions; Economic assessment; Environmental assessment; Temperature-humidity index; Heat stress