Intramammary infections before calving and in early lactation have a negative impact on the development of the mammary gland, udder health, the risk of clinical mastitis in early lactation, the risk of premature culling and future milk production in dairy heifers. The aim of this study was to reveal whether and how the somatic cell count of the first dairy herd improvement (DHI) affects the 305 day milk yield (energy corrected milk) of the first lactation in German dairy heifers. It should also be examined whether the threshold of 100,000 cells/ml used for herd analysis in Germany is suitable for estimating possible economic losses as the threshold of 200,000 cells/ml is often used in other countries. In addition, it should be examined whether a milk loss, which is associated with an increased initial SCC, differs between different German dairy cattle breeds. For this study, the DHI data of 49,467 heifers reared on 2413 German dairy farms located in Schleswig-Holstein between October 2015 and June 2016 were analyzed. Heifers with a SCC in the first DHI test of > 100,000 cells/ml showed a significantly (p <0.001) lower milk yield (on average -98.3 kg; 95% confidence interval (CI): -116.4 - -80.2) during the first lactation compared to heifers with an SCC ≤ 100,000 cells/ml. Heifers with a SCC in the first DHI test of > 200,000 cells/ml also showed a significantly (p <0.001) lower milk yield (on average -96.3 kg; 95% CI: -118.4 - -74.2) in the first lactation compared to heifers with a SCC ≤ 200,000 cells/ml. The effect of milk loss due to an increased initial SCC did not differ significantly between the breeds analysed. These results show that it is possible to use both thresholds of the SCC for assessing udder health in individual heifers and at herd level. However, the present study only shows the relationship between increased SCC and the loss of milk yield measured in different German breeds of dairy heifers. Future studies must validate further risk factors that influence the udder health of dairy heifers.