The biochemical parameters of the blood give us clues about the health of the animals. In the animals studied, the biochemical parameters fall within the normal limits.The biochemical parameters of the blood are influenced by lactation as follows: ALT (U/L), has the highest average values in lactation 2 (14.18 ± 0.55 U/L), and in lactation 4 (15.71 ± 0.21 U/L). AST (U/L) in lactation I showed the lowest values, 244 ± 5.01 (U/L) and 256.28 ± 2.85 (U/L) in lactation IV. Total protein (g/L) varied in the range 61.28 ± 3.36 (g/L) lactation I and lactation IV, 67.86 ± 1.96 (g/L). Total bilirubin (mmol/L), in lactation I is 7.33 ± 0.57 (mmol/L) and in IV lactation 8.61 ± 0.43 (mmol/L). Magnesium behaves similar to total bilirubin having the lowest values in lactation I, 0.72 ± 0.05 (mmol/L) and 0.83 ± 0.04 (mmol/L) in lactation IV.