Age related changes in body size and gonadal development of growing Frieswal bulls

Abstract

The study was conducted on 20 young Frieswal bulls (cross between Holstein - Friesian (HF) x Sahiwal; having 5/8 exotic (HF) inheritance) during their pubertal period (9-18 months old) to find out the age related changes in body and gonadal development. The overall body weight of young Frieswal bulls at 9 months of age was ]95.20±4.03 kg which increased nearly 2 folds (368.00±:7.18 kg) at 18 months of age. The hcalt girth. body length. rear girth and height at withers increased to 23. 24.3, 19 and 17.9%, respectively, during this period. Scrotal circumference. testicular length. breadth and width/thickness increased almost linearly during the pubertal period. At 18 months of age. paired testicular volume (PTV) and weight (PTW) was increased by 2.75 and 2.03 times respectively. from 9 months of age. Overall dimensions of the left testicle were always less than that of the right 1 throughout the entire study period. In different stages of growth period, the PTV increased by 49.39, 48.96 and 23.80% during 12, 15 and 18 months of age, respectively, and the corresponding values in PTW were 28.45, 24.24 and 27.30% respectively. The testicular weight: volume ratio was 1.3: 1. 1.1: 1.0.9: 1 and 0.9: 1 at 9,12,15 and 18 months or age, respectively. which showed a declined trend with advancement of age. During 9 to 15 months of age the PTV and P'T W increased by 122.5 und 59.57%. respectively. whereas during 1.6 to 18 mouths it was 23.81 and 27.30% respectively. During puberty gonadal development was faster as compared to general body (weight and measurements) deVelopment and within the pubertal period testicular development was faster in eadier part (9-15 months) as compared to the later part (16- 18 months of age).