Abstract
Semen characteristics indicate reproductive performance of bulls. We estimated genetic parameters of semen characteristics using multiple-trait animal model. Data were semen records of 1,281 bulls collected by the Genetics Hokkaido between 2005 and 2014 with their pedigree records. Data of semen characteristics contained volume per ejaculate (mL), sperm concentration (×108/mL), number of sperm per ejaculate (×108), progressive motility index of sperm (MOT) and MOT after freeze-thawing. Posterior means of heritabilities were 0.12, 0.13, 0.06, 0.11 and 0.20 for volume per ejaculate, sperm concentration, number of sperm per ejaculate, MOT and MOT after freeze-thawing, respectively. Posterior means of repeatabilities were 0.25, 0.39, 0.16, 0.62 and 0.72 for volume per ejaculate, sperm concentration, number of sperm per ejaculate, MOT and MOT after freeze-thawing, respectively. The MOT after freeze-thawing has high repeatability. Therefore, MOT after freeze-thawing from young bull is valuable as a predictor of those from mature bull.
