Evaluation of hepatic markers and body weight gain in growing and finishing steers

Background: The liver plays an important role in nutrient metabolism, in detoxification and excretion of hydrophobic metabolites, and in the synthesis of most circulating proteins. Thus, enhanced knowledge of the processes that regulate liver function in beef cattle production stages can lead to significant improvements in their management. Aims: The authors studied the levels of some serum liver parameters during growing and finishing stages of steers. Methods: Blood samples were collected from (n = 60) steers at day 1 and at day 21 and 42 days after the start of the growing (group 1 n = 30: mean body weight (BW) 430 ± 5.8 Kg) or finishing (group 2 n = 30: mean BW 591 ± 5.3 Kg) phases. Steers from both groups were separated into two subgroups (A and B, respectively) according to the percentage of body weight gain (%WG). Subgroup A steers had a lower mean %WG than subgroup B steers. Serum total proteins (TP), albumin, globulins, serum urea nitrogen (SUN), total and conjugated bilirubin (TB, CB), aspartate amino transferase (AST), and gamma-glutamyltransferase (GGT) were assessed in order to evaluate significant differences between groups and subgroups. Results: All parameters showed significant differences between the phases and between groups with the exception of AST and GGT. Mean ± S.D. of %WG was 11.07 ± 1.95 for group 1 and 9.84 ± 0.77 % for group 2. For group 1 steers, there was a significant difference on SUN concentration and GGT activity between subgroup A and subgroup B. Conclusions: These findings suggest that hepatic markers in steers are influenced by production stages and improve the knowledge about the effect of growing and finishing phases on their hepatic markers. Furthermore, it underlies the importance of monitoring body weight gain in order to obtain a maximizing profitability.