This study was carried out to examine the effects of individual and paternal inbreeding on the performance of several reproductive traits. Therefore, records of Holstein heifers from the dairy herds of Isfahan during 1991 - 2013 were used to estimate inbreeding coefficient. The pedigree was contained 108253 animals during seventh generations. In the pedigree, we have got 5.4 percent with unknown dams, 0.04 percent with unknown sires and 7.9 percent with unknown sires and dams. Inbreeding coefficient according to the base generation was estimated 1.12 percent for whole population. Although73.4 percent of the animals in current study were inbred, but the average of inbreeding of them was 1.53 percent. The reproductive traits in this study were conception rate, age at first birth and number of insemination. Additionally, amount of inbreeding depression was studied. Results indicated that regression coefficients for conception rate, age at first calving and number of insemination were -0.405, 0.57 and 0.11, respectively, for 1 percent increasing in rate of inbreeding. The changes of inbreeding coefficients showed that by increasing the mating inbreeding, reproductive traits were affected. Also, during the different years, family mating, though not very close, but rising. Hence, during the early years the number of inbred animals were lower but due to close mating average inbreeding coefficients was increased. The paternal inbreeding coefficients was computed about .35 percent. In this study paternal inbreeding coefficient was considered as a Keywords : Jnbreeding coefficient, Inbreeding depression, reproductive traits, Holstein Cows
