Estimation Genetic Parameters of Semen Quality Traits in Iranian Holstein Bulls

: For the design of any successful breeding program, knowledge about semen quality traits is greatly important and per-required. Reproductive performance is of paramount economic importance in the livestock industry, including dairy cattle production. Despite the importance of the quality of semen used in artificial insemination to the reproductive success of dairy herds, few studies have estimated the extent of genetic variability in semen quality traits. In this study, records collected by Jahed (station 1) and Sheykh Hasan (station 2) breeder centers from 1991 to 2013, were used to estimate variance components, heritability, and repeatability for sperm quality traits. Records information was analyzed by wombat software. Data were analyzed by using the repeatability model in three models, first by year-season-station, secondary by station, and third by year. In the first model, maximum heritability and repeatability (0.9755) estimated the total number of sperm in milt ejaculation trait. In the second model, maximum heritability (0.96), that was in Jahed center, estimated for total number sperm in milt ejaculation, maximum repeatability (1), that was in Jahed center, too, estimated for sperm volume and maximum repeatability (1), that was in both breeding centers, estimated for motility to post-thaw motile ratio trait. In the third model, maximum heritability and repeatability (0.54), estimated for (liveafmil) trait. Maximum heritability and repeatability estimates for the total number of post-thaw motile sperm per milt ejaculation trait were 0.19 and 0.32, respectively. The objectives of this study were to estimate genetic parameters of semen quality traits using data from routine semen collection in the Iranian Holstein.