Table 2 presents the test results on the endocrine and metabolic parameters in transition cows
(Group A, from day 20 to day 10 before calving; Group B, from day 10 to day 1 before calving; Group C, puerperal healthy cows; Group D, puerperal ketotic cows).Table 2 shows significant changes in most blood parameters in ketotic cows. Mean serum insulin concentrations for all animals were not significantly different (p > 0.05) throughout the experimental period due to high individual variability, with the highest insulin level found in puerperal healthy cows. Serum cortisol concentrations insignificantly increased (p > 0.05) to a peak before calving (Group B), then dropped again to an approximately steady level in puerperal healthy and ketotic cows. Blood serum T3 (p < 0.01) and T4 (p < 0.05) were significantly lower in ketotic cows than in healthy cows. Blood glucose was significantly lower in ketotic cows compared to healthy cows (p < 0.01). Biochemical analysis of lipids and ketone bodies in the blood serum showed significantly higher values (p < 0.01) of NEFA and BHB in ketotic cows such as significantly lower levels of TG (p < 0.01) and total cholesterol (p < 0.05), compared to respective values in healthy cows.