The objective of this study was to investigate the role of diet management on rumen pH dynamics during the weaning transition. Thirty-six Holstein bull calves were divided into 4 treatments based on diet and harvest age: calves fed milk and hay only, harvested pre-weaning (PRE-M); milk, hay, and starter, harvested pre-weaning (PRE-S); milk, hay, and starter, harvested post-weaning (POST-S); milk, hay, and starter, harvested post-weaning, with supplemental butyrate fed during the weaning transition at 1% DMI (POST-B). All animals were housed individually and had ad libitum access to water, hay, and calf starter. Calves were fed milk replacer (28% CP, 18% EE) twice daily. Until 6 weeks of age, calves were fed a maximum of 1200 g/d of milk replacer. Then, milk replacer was reduced to 900 g/d for wk 7, 600 g/d for wk 8, then weaned. Calves were harvested at the end of wk 6 (PRE-M, PRE-S), or at the end of wk 9 (POST-S, POST-B). One week before harvest, rumen pH was measured every 2 min for 7 d. Calf starter and hay intake were measured daily, while body weight and blood were sampled weekly. Mean rumen pH was not different among PRE-M, PRE-S, POST-S, and POST-B (6.17 vs. 7.45 vs. 6.40 vs. 5.83 ± 0.66, respectively; P = 0.27). The duration where rumen pH was below 5.8 was also not different among PRE-M, PRE-S, POST-S, and POST-B treatments (485 vs. 280 vs. 209 vs. 730 ± 201 min/d; P = 0.24). No differences in plasma glucose concentrations were found among the treatments. No differences in plasma BHBA concentrations were detected among treatments before weaning or after weaning. During the weaning transition, plasma BHBA concentrations were higher in the POST-B than the POST-S treatment in wk 7 (1.28 ± 0.10 vs. 0.92 ± 0.10 µM, respectively; P = 0.04). After weaning, there was no difference in hay intake, but calf starter intake was greater in POST-B than in POST-S (2698 ± 281 vs. 1839 ± 281 g/d, respectively; P < 0.01). These data indicate that rumen pH profile does not appear to shift during the weaning transition and that dietary supplementation with butyrate may improve starter intake post-weaning.