A light-emitting diode (LED) is most efficient in terms of economic benefits. The aim of the present study was to evaluate the effects of LED lighting intensity on milk production, milk composition, and the immune response of Holstein cows. Thirty-eight lactating cows were assigned to four experimental groups: control group (exposed natural daylight without LED light) and three LED treatment group (50 lux; natural daylight and 6 h LED light of 50 lux intensity, 100 lux; natural daylight and 6 h LED light of 100 lux intensity, 200 lux; natural daylight and 6 h LED light of 200 lux intensity). There was a significant effect on the decrease ratio in milk production in 200 lux group. Lactose was significantly increased in 100 lux than the other LED treated groups. In addition to the hemolytic biochemical analysis, AST and β-HB were significantly increased in the 50 lux than the other groups. Prolactin and IGF-1 levels were significantly increased in 200 lux compared to other groups. Besides, cortisol was significantly higher in 50 lux and lowered in the 200 lux than the control, while IgA and IgG were not significant among the groups. Therefore, it was concluded that LED lighting intensity had some impact on blood parameters and immune responses in dairy cows with increased milk production.

Ⅰ. Introduction
Ⅱ. Materials and Methods
    1. Animals and Experimental Design
    2. Milk Production and Composition
    3. Blood Sample Collection and Assay Procedure
    4. Measurement of Immunoglobulin and Hormones in Blood
    5. Statistical Analysis
Ⅲ. Results and Discussion
    1. Milk Production
    2. Milk Composition
    3. Blood Biochemical Parameter Analysis
    4. Activities of Immunoglobulin (IgA & IgG) and Hormones
Ⅳ. Conclusion
References

• Park Jin-Ryong(Department of Animal Biotechnology, Chonbuk National University) | 박진룡
• Belal Shah-Ahmed(Department of Poultry Science, Sylhet Agricultural University) | 샤메드
• Na Chong-Sam(Department of Animal Biotechnology, Chonbuk National University)
• Shim Kwan-Seob(Department of Animal Biotechnology, Chonbuk National University) | 심관섭 Corresponding author