No abstract

This study aimed to evaluate the influence of bull age on fresh semen traits of Bali bulls. A total of 316 semen samples collected from six Bali bulls aged at 4, 6, and 8 years old (2 bulls of each age) were involved in this study. Fresh semen traits measured were semen volume, sperm concentration, total sperm, sperm motility, and total motile sperm. Data of fresh semen traits were analyzed using analysis of variance, followed by Duncan test to separate means. Additionally, data of semen volume, sperm concentration, and sperm motility were subjected to the Pearson correlation test. The result showed that the semen volume of Bali bulls increased from 4 to 6 years old (P<0.05) but then tended to decrease in 8 years old bulls. However, sperm concentration remained unchanged (P>0.05) among different ages. At 6-years old, Bali bulls had the highest total sperm (P<0.05), but their sperm motility was the lowest (P<0.05). Furthermore, the total motile sperm of Bali bulls did not differ among bull age (P>0.05). Negative correlations were found between semen volume with sperm concentration (P<0.01) and motility (P<0.01), while a positive correlation was recorded between sperm concentration and motility (P<0.05). It could be concluded that the age had an unclear pattern effect on fresh semen traits of Bali bulls at 4, 6, and 8 years old. At these ages, the Bali bulls had equal fresh semen production potency to be used in artificial insemination programs.