author(s)
Attaur Rahman, Saeed Ahmad Soomro, Hameed u Rehman, Sultan Ayaz, Sadeeq ur Rahman,Wali Mohammad Achakzai,Shagufta Saddozai, Tahir Usman, Muhammad Tariq, Muhammad Arshad Iqbal and Kausar Saeed

abstract
Recombinant Bovine somatotropin (rbST) is one of the hormones potentially used as growth promoters in feedlot animals; however, limited data is available regarding its effects on blood biochemistry of Kundhi buffalo calves (KBC). Therefore, the current study was conducted to analyze the effects of rbST on blood biochemistry of KBC. For this purpose, selected calves were randomly distributed into three groups (A, B and C) with four calves per group. Group A was kept as control, while group B and C were treated with rbST @ 0.5 mg- and 1.0 mg/kg body weight (BW) fortnightly, respectively. After eleven weeks of treatment, blood samples were analyzed for blood metabolites i.e. glucose, protein and lipids, which are major metabolic substrates in the blood required for the growth and fattening of calves and used as fattening indicators. Our data revealed that blood glucose was increased significantly in group C (74.45 ± 0.71 mg/dl) and B (70.50 ± 0.28 mg/dl) as compared to control group A (62.17 ± 1.30 mg/dl). Protein level showed significant difference between rbST treated groups C (7.92 ± 0.07 g/dl) and B (7.44 ± 0.08 g/dl) and control group A (6.44 ± 0.11g/dl). Consistent with the increase in blood metabolites, body weight of group C was significantly (P<0.05) increased, followed by group B and A, respectively. Moreover, feed intake was recorded significantly differently (P<0.005) between treated and untreated groups. Similarly, feed efficiency rate (FCR) was found significantly improved (P<0.005) in group C and B compared to group A. Furthermore, total lipid level was increased significantly in group C (521.39 ± 3.34 mg/dl) and B (516.07 ± 3.72 mg/dl) as compared to control group A (469.65 ± 7.03 mg/dl), but the difference was non-significant between group B and C. Calcium level was significantly different between rbST treated groups C (8.97 ± 0.13 mg/dl) and B (8.14 ± 0.15g/dl) and control group A (6.56 ± 0.11). Finally, non-significant difference was found in sodium and potassium levels between rbST treated groups and control group. Overall, our data revealed that fattening indicators have been significantly enhanced in calves treated with rbST@1 mg/kg BW and that this could be an effective dose for better outcomes.