Diet is known to affect rumen growth and development. Calves fed an all liquid diet have smaller and less developed rumens and may have a decreased ability to absorb volatile fatty acids (VFA) compared with calves fed liquid and dry feed. However, it is unknown how these differentially developed rumens would respond when challenged with a defined VFA buffer. The objective of this study was to assess effects of 2 different feeding programs on VFA transporter abundance in preweaned calves. Neonatal Holstein bull calves (n = 12) were individually housed and randomly assigned to 1 of 2 treatment diets. Treatment diets were milk replacer only (MRO; n = 6) or milk replacer and starter (MRS; n = 6); diets were isoenergetic (3.87 ± 0.06 MCal of ME/d) and isonitrogenous (0.17 ± 0.003 kg/d of apparent digestible protein). Milk replacer was 22% CP, 21.5% fat (DM basis) while the textured calf starter was 21.5% CP (DM basis). Feed and ad libitum water intakes were recorded daily; body growth was measured weekly. Calves were exposed to a defined VFA buffer (acetate: 143 mM, propionate: 100 mM, butyrate: 40.5 mM) 6 h before euthanasia on d 43 ± 1. Rumen tissues were obtained from the ventral sac region and processed for morphological and immunohistochemical analyses of the VFA transporters monocarboxylate transporter 1 (MCT1) and 4 (MCT4). Data were analyzed using PROC MIXED in SAS 9.4 with the following effects: fixed = treatment (including week and interaction for repeated measures) and random = calf nested within treatment. Body growth did not differ between treatments, but empty reticulo-rumens were heavier in MRS than MRO calves (0.67 vs 0.39 ± 0.04 kg; P = 0.001) and MRS calves had larger papillae area (0.76 vs 15 ± 0.08 mm²; P = 0.001). No differences between treatments in protein abundance of MCT1 and MCT4 per unit area were observed. These results indicate that the extrapolated increase in total abundance of MCT1 and MCT4 in MRS calves is not due to increased transporter density per unit area. Modeling of VFA absorption data will help determine the proportion of VFA undergoing protein-mediated transport via MCT1 and MCT4 versus those that are passively diffused.