The effect of seasonal thermal stress on milk production and milk compositions of Korean Holstein and Jersey cows

Abstract

Objective: In this study we investigated the effect of seasonal thermal stress on milk production and milk compositions between Holstein and Jersey dairy cows under the temperateclimate in Korea.Methods: A total of 9 Holstein lactating dairy cows (2.0±0.11 parity) which had a daily milk yield of 29.77±0.45 kg, and days in milk of 111.2±10.29 were selected similarly at the beginning of the experiments in each season. Also, a total of 9 Jersey lactating dairy cows (1.7±0.12 parity) which had a daily milk yield of 20.01±0.43 kg, and days in milk of 114.0±9.74 were selected similarly at the beginning of the experiments.Results: Results showed that the average ambient temperature (°C) and temperature-humidity index (THI) were higher in summer, and were lower in winter (p<0.05). The average relative humidity (RH, %) was higher in autumn than that of other seasons (p<0.05). Milk production was significantly decreased (Holstein 29.02 kg/d and Jersey 19.75 kg/d) in autumn than in other seasons (Holstein 30.14 kg/d and Jersey 20.96 kg/d). However, the milk production was negatively correlated in Holstein cows, and positively correlated in Jersey cows with THI values increased from 16 to 80. In addition, milk yield was increased by 15% in Holstein cows and decreased by 11% in Jersey cows with the THI values increased from 16 to 20. The fat and protein content percentage was significantly higher in Jersey milk than in Holstein milk, furthermore the fat and protein content yield was higher in Jersey cow milk than that of Holstein cow’s milk with all THIs.Conclusion: From the study results, we concluded that Jersey cows might be less adaptable to low temperature of the winter, and this would have a negative impact on dairy farmer income since Korea’s milk price estimation system places a higher value on milk yield than on milk compositions or sanitary grades.

Effects of Environmental Temperature and Humidity on Milk Composition, Microbial Load, and Somatic Cells in Milk of Holstein Dairy Cows in the Northeast Regions of Iran

“…We postulate, from these data, that milk composition was more susceptible to temperature than humidity in this study. In line with our results, Lim et al [ 52 ] stated that, in summer—when the average ambient temperature (°C) and temperature–humidity index (THI) were higher—there was a negative correlation between these factors and milk production, in addition to the proportions of milk fat and protein. This was explained by Johnson [ 53 ] as greater production of heat during summer speeding up the rate of decline in milk production for cows.…”

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

“…Our study results are supported by Bohmanova et al [27] who reported that even with use of evaporative cooling, THI can't drop below 72, this may explain the sharp decline of milk production from June to August. Lim et al [28] reported that the greater heat production can explain the increasing rate of decline in milk yield for cows. Also, Bohmanova et al [27] showed milk production begins to recover from HS in October when THI was < 72.…”

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

“…Our study results are supported by Bohmanova et al [25] who reported that even with use of evaporative cooling, THI can't drop below 72, this may explain the sharp decline of milk production from June to August. Dong-Hyun Lim et al [26] reported that the greater heat production can explain the increasing rate of decline in milk yield for cows. Also, Bohmanova et al [25] showed milk production begins to recover from HS in October when THI was <72.…”