Abstract
In this study, effects of bovine somatotropin (bST) on libido, serum testosterone, haematological indices and serum
biochemical metabolites in Sahiwal bulls were investigated. Bulls of the treatment group (n=3) were given bST @ 500 mg
weekly, for 10 weeks, while control bulls (n=3) were injected with equal volume of normal saline. Reaction time of these
bulls was recorded fortnightly. Blood samples collected fortnightly were analyzed for haematological parameters, while,
serum samples were assayed for testosterone and biochemical metabolites. Results revealed that bST treatment of Sahiwal
bulls significantly decreased reaction time (5.25±0.28 vs 7.50±0.42 sec) and increased serum testosterone concentrations
(14.02±0.19 vs 12.55±0.44 ng/ml) compared to controls (P<0.05). Similarly, total leukocyte counts (10.49±0.83 vs 7.91±0.38
x 103
/ul) were increased, while PCV (36.78±0.64 vs 40.78±1.28%), MCV (51.02±0.47 vs 54.90±0.68fl) and MCH
(16.20±0.10 vs 16.86±0.14 pg) decreased. Serum globulin (5.43±0.11 vs 5.17±0.04 G/dl) was higher and serum urea
(12±0.47 vs 15.33±0.82 mg/dl) lower in treated bulls (P<0.05). However, bST had no effect on blood Hb, RBC counts,
MCHC, ESR, DLC, platelets counts, serum total proteins, albumin, glucose and SGPT activity. Thus, treatment of bulls with
bST improved libido, increased testosterone, total leukocyte counts and serum globulin, and decreased PCV, MCV, MCH
and serum urea.
