The aim of this study was to explore the effects of parity and lactation stage on somatic cell counts in dairy herd improvement (DHI) milk samples and milk production loss in dairy cows. The results indicated that the somatic cell score (SCS) was increased with parity, and SCSs at different stages of lactation performance in different parities were different. SCS was increased with lactation time in first-parity dairy cows and SCS values were significantly different at three lactation stages (P < 0.05). The same trend was observed for SCS in second- and third-parity cows; SCS was higher at the early lactation stage than at the middle lactation stage, and its values at the two stages were significantly lower than that at the late lactation stage (P < 0.05). Milk production loss in dairy cows generally rose with parity and was higher at the early and late stages of lactation than at the middle stage.