The present study was aimed to investigate the association of scrotal circumference (SC) with sperm production and semen quality in Sahiwal bulls. Mature semen donor bulls (n=76), 3 to 5 years old, were divided into three groups according to SC: GI, GII, and GIII with 28-30, 31-35, and >35 cm, respectively. Semen was collected using artificial vagina once a week for five successive weeks. Positive correlations (P<0.05) were observed between SC and mean ejaculate volume (r=0.2) and percentage of live sperm (r=0.12). Mean volume per ejaculate differed amongst the GI, GII, and GIII (4.3±0.1, 5.0±0.1, 5.7±0.1; P<0.05). Sperm concentration and percentage of live sperm were greater (P<0.05) in GII and GIII compared to GI. Scrotal circumference was not significantly correlated with sperm motility, membrane integrity, normal acrosome or morphology; no significant differences among groups were observed for these endpoints. In conclusion, greater SC in Sahiwal bulls was associated with greater production of live sperm.

Key words: Sahiwal bull, Scrotal circumference, Semen quality, Sperm production