Effects of age and breed on semen quality of beef bull sires in an indonesian artificial insemination center

The research work was carried out to evaluate the effects of age and breed on semen quality of beef bull sires. The experimental site was located at Singosari National Artificial Insemination Center, Malang, Indonesia. A total of 180 ejaculate semen which were collected from 9 beef bull sires (3 Bali, 3 Limousin, and 3 Simmental bulls) aged at either 2 years (young), 5 years (middle), or 12 years (old) were used in this study. The semen was collected twice weekly and directly evaluated for their ejaculate volume (EV), sperm concentration (SC), total sperm number (TSN), individual sperm motility (ISM), post-thawing sperm motility (PTSM), and frozen semen dose (FSD). The study showed that there were age-related changes on semen quality of beef bull sires, except for ISM and PTSM. The peak (p <0.05) EV was achieved by old bulls, but with the lowest (p <0.05) SC, TSN, and FSD. The breeds also contributed to the variation on sperm quality. Limousin bulls had the highest (p<0.05) EV compared to other breeds. The higher (p<0.05) SC, TSN, and FSD were observed in Simmental and Limousin bulls compared to Bali bulls. However, in the case of ISM and PTSM, Bali bulls had greater value (p<0.05) than other breeds. Moreover, the results underlined that there were age x breed interaction effects (p<0.05) on all semen quality parameters observed in this study. Overall, the age effect on frozen semen production of beef bull sires is varied among breeds studied here. It is recommended to provide special management condition on each breed of beef bull sires to optimize frozen semen production.