Table 6. Biochemical indices status in lactating dairy cows

Item Control T1 T2 T3 SEM p-value
Melatonin (pg/mL) 25.55a 23.72a 17.44b 17.03b 0.78 < 0.001
Cortisol (pg/mL) 1,437.61a 1,224.31b 953.03c 935.52c 44.83 < 0.001
Total protein (g/dL) 55.90 59.20 62.72 61.69 1.45 0.389
Albumin (g/dL) 2.28 2.42 2.62 2.63 0.07 0.198
BUN (mg/dL) 15.26b 17.94a 18.54a 19.36a 0.40 0.001
Creatinine (mg/dL) 1.43 1.46 1.53 1.63 0.03 0.059
Glucose (mg/dL) 49.83 49.17 51.92 49.33 0.77 0.590
Non-esterified fatty acid (mg/dL) 42.92 29.58 31.92 34.25 3.25 0.531
Triglyceride (mg/dL) 4.42 4.75 4.83 5.58 0.23 0.357
G-GTP (IU/L) 18.58 24.58 26.83 24.58 2.73 0.768
GOT (AST) (IU/L) 47.17 52.17 56.25 58.83 2.30 0.331
GPT (ALT) (IU/L) 14.42c 18.08bc 21.08ab 24.08a 0.83 < 0.001
Cholesterol (mg/dL) 121.92 137.83 147.17 145.25 5.33 0.352
The blood sample was collected via jugular venipuncture of each cow at 14:00 h.
Control, natural photoperiod; T1, LDPP (day : night = 16 : 8 h) with 50 Lux of the light intensity; T2, LDPP with 100 Lux; T3, LDPP with 200 Lux.
Denote comparison made within row.
BUN, blood urea nitrogen; GTP, guanosine triphosphate; GOT, glutamic oxalacetic transaminase; AST, aspartate aminotransferase; GPT, glutamic pyruvate transaminase; ALT, alanine aminotransferase.