OBJECTIVE Calving ease (CE) is a complex reproductive trait of economic importance in dairy cattle. This study was aimed to investigate the genetic merits of CE for Holsteins in Korea. METHODS A total of 297,614 field records of CE, from 2000 to 2015, from first parity Holstein heifers were recorded initially. After necessary data pruning such as age at first calving (18 to 42 mo), gestation ...

effects of inbreeding coefficient on estimates of genetic parameters, breeding values and genetic trends for production traits (milk, fat and protein yields), reproduction traits (age at the first calving, interval between first insemination to conception, calving interval, interval between calving to first insemination, and calving ease) as well as longevity of holstein cattle in iran were stu...

Field records from the American Simmental Association were used to estimate genetic parameters for direct and maternal effects of traits associated with dystocia. Estimates of the additive genetic variances of direct and maternal effects and of the additive genetic covariances of direct and maternal effects were calculated by equating the sire variance component, maternal grandsire variance com...

The experiment involved observations of 2,514 Holstein-Friesian cows to determine the effects of environmental factors (cow's age, calving season, weight and sex of calves, housing system) and genetic factors on gestation length in dairy cattle and the correlation between gestation length and other reproductive traits (calving ease, stillbirth rates and placental expulsion). Genetic parameters ...