INS and Insulin resistance: The NAD:NADP ratio showed a positive correlation with glucose, insulin, GLU:INS and the RQUICKI index of insulin resistance, triglycerides and cholesterol and a negative correlation with NEFA, BHB, GGT and urea in cows receiving niacin, while in the control group cows showed a positive correlation with insulin and a negative correlation with albumin and urea (Table 4, Figure 5).