Seasonal variations of some hematochemical parameters in Holstein bovine under the same livestock conditions

In this study, the effect of season, gender and productive status on some hematochemical parameters was evaluated in clinically healthy Holstein cattle. A total of 18 bovines were enrolled in the study and equally divided in three groups, according to their gender and lactation class: Group A (dairy cows in first lactation class); Group B (dairy cows in third lactation class); Group C (bulls). Groups A and B were in the same productive period (dry period in winter, early lactation in spring, mild lactation in summer, end of lactation in autumn). Samples were collected of the animals’ blood at the same time of the day (8:00) in January (winter season), April (spring season), July (summer season) and October (autumn season), and concentrations of glucose, calcium (Ca), magnesium (Mg), potassium (K), sodium (Na), phosphorus (P), total protein, albumin, creatinine, urea, aspartate aminotransferase (AST), alanine aminotransferase (ALT) were evaluated. A seasonal effect (P<0.05) was found for Mg, creatinine, urea and glucose values in all Groups; Ca, Na, K, AST, ALT, triglycerides and cholesterol values were influenced by season in Group C (P<0.05). Productive status affected Ca, AST, ALT, triglycerides and cholesterol values (P<0.05) in Groups A and B; gender significantly influenced AST and ALT values (P<0.05). This study suggests that seasonal and physiological conditions have to be taken into consideration for correct interpretation of serum chemistry in bovine, in order to establish an accurate interpretation of laboratory data, which is critical in the diagnosis, prognosis and treatment of diseases.