Endocrine Abstracts

In this study, effects of bovine somatotropin on libido, serum testosterone, hematological indices and certain serum biochemical metabolites in Sahiwal bulls were investigated. Six adult Sahiwal bulls with clinically normal reproductive tract and kept at the Semen Production Unit, Qadirabad, Sahiwal, Pakistan were used. These bulls were divided into two equal groups, i.e. treatment and control. Bulls of the treatment group were given bovine somatotropin (bST) at of 500 mg weekly, for 10 weeks, while bulls of the control group were injected with equal volume of normal saline according to the same protocol as for treatment group. Libido of these bulls was recorded fortnightly in terms of reaction time. Blood samples collected fortnightly from these bulls were analyzed for hematological parameters, while, serum samples were assayed for concentrations of testosterone and certain biochemical metabolites. Results revealed that bST treatment of Sahiwal bulls significantly decreased reaction time (5.25±0.28 vs 7.50±0.42 s) and increased serum testosterone concentrations (14.02±0.19 vs 12.55±0.44 ng/ml) compared to controls (P<0.05). Among hematological parameters, total leukocyte counts (10.49±0.83 vs 7.91±0.38×10³/μl) increased, while PCV (36.78±0.64 vs 40.78±1.28%), MCV (51.02±0.47 vs 54.90±0.68 fl) and MCH (16.20±0.10 vs 16.86±0.14 pg) decreased significantly. However, bST treatment had no effect on blood Hb, RBC counts, MCHC, ESR, differential leukocytic count and platelets count. 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 bST treated bulls (P<0.05). However, bST had no effect on serum total proteins, albumin, glucose and SGPT activity. Thus, treatment of bulls with bST improved libido, increased testosterone, total leukocyte counts and serum concentration of globulin, and decreased PCV, MCV, MCH and serum urea.