Semen Ejaculates Characteristics, in vitro Fertility and Their Interrelationships in Sahiwal Bull Semen

This study aimed at determining the physico-morphological attributes, in vitro fertility and their interrelationships in semen of Sahiwal bulls. Semen samples were collected weekly for 6 weeks from ten mature Sahiwal bulls divided randomly into 5 groups. The mean (±SEM) of ejaculate volume (mL), mass activity (score 0-5), progressive sperm motility (%), sperm concentration (10 6 /mL), live sperm (%), abnormal sperm (%), intact acrosome (%), hypo-osmotic swelling (HOS) positive sperm (%), sperm penetration distance (SPD, mm) were 4.28, 3.17, 76.73, 1185.53, 83.37, 9.97, 82.70, 79.00 and 56.85, respectively. The bulls varied significantly (P<0.05) in all their ejaculates characteristics Moreover, HOS positive sperm also had significant (P<0.01) positive correlation with mass activity (r=0.756), progressively motile sperm (r=0.374), live sperm (r=0.395) and SPD (r=0.681), and negative correlation with abnormal sperm (r=-0.463). Sperm penetration distance has significant (P<0.05) positive correlation with mass activity (r=0.776), progressively motile sperm (r=0.653), sperm concentration (r=0.365) and HOS positive sperm (r=0.681), and negative correlation with intact acrosome (r=-0.415). Overall semen quality of Sahiwal bulls was found optimum for use in breeding programme.