Hyperketonemia has a relatively high prevalence of 22.6% on Quebec Holstein farms. The objectives of this study were to identify the consequences of elevated milk β-hydroxybutyrate (BHB) on whole-lactation milk performance and on reproductive success. Records from 505,412 Holstein cow observations (159,525 first parity, 132,694 s parity and 213,193 third and later parity) from 3,551 herds were included in the analysis. Data were retrieved from Valacta’s database from cows that calved between 2011 and 2017. Cows were grouped based on parity and according to the milk BHB concentration on first test-day between 5 and 35 d in milk (DIM) into negative (NEG; <0.15mM), suspect (SUS; 0.15 to 0.19 mM), positive (POS; ≥20 mM). Mixed model analyses with PROC MIXED of SAS including herd as a random effect revealed that POS cows produced greater milk fat (376 vs 361 kg SEM 6.4; P < 0.01), as well as more energy-corrected milk (9,419 vs 9,153 kg SEM 146; P < 0.01) over a 305-d lactation compared with NEG cows. However, analysis of reproductive performance revealed that POS cows experienced more days open (149 vs 126 d SEM 3.6; P < 0.01), had a greater interval from first service to conception (41 vs 31 d SEM 1.7; P < 0.05) and required more services per conception (2.1 vs 1.8 SEM 0.1; P < 0.01) than NEG cows. These changes in reproductive parameters were observed across parities. Additionally, a survival analysis with PROC LIFETEST and PROC PHREG of SAS revealed reduced pregnancy rates for POS cows, especially for multiparous cows. Lastly, a frequency analysis with PROC GENMOD of SAS was used to assess culling rates, where by 60 DIM, the culling rates were higher for POS cows (3.4 vs 2.6% ± 0.3; P < 0.01) compared with NEG cows. Overall, high milk performance was associated with high milk BHB levels. Elevated BHB levels significantly hindered the reproductive performance of these cows and increased their chances of being culled from the herd.