Interactions between the physical form of starter (mashed versus textured) and corn silage provision on performance, rumen fermentation, and structural growth of Holstein calves.

Introducing forage in the young calf diet during the milk-feeding period stimulates rumen development. It was hypothesized that performance in dairy calves would depend on forage provision and starter physical form such that the textured starter (TS) feed with corn silage (CS) supplementation would benefit calf performance. This study evaluates the effects of the physical form of starter diets and CS supplementation on performance, rumen fermentation characteristics, and structural growth of dairy calves. Forty-eight 3-d-old Holstein dairy calves with a mean starting BW of 42.1 kg (SD 2.4) were used in a 2 × 2 factorial arrangement with the factors dietary CS level (0 or 15% on DM basis) and physical form of starter (mashed vs. textured). Individually housed calves were randomly assigned ( = 12 calves per treatment: 6 males and 6 females) to 4 treatments: 1) a mashed starter (MS) feed with no CS (MS-NCS), 2) a MS feed with CS (MS-CS), 3) a TS feed with no CS (TS-NCS), and 4) a TS feed with CS (TS-CS). The calves had ad libitum access to water and starter throughout the study. All calves were weaned on d 56 of age and remained in the study until d 66. The interaction of the physical form of the starter and CS provision was significant ( < 0.01) for the starter intake, with the greatest intake for TS-CS treatment during the preweaning and overall periods. Regardless of the physical form of starter, starter intake, ADG, weaning BW, final BW, ruminal pH, the molar proportion of acetate, and the acetate-to-propionate ratio were greater ( < 0.01) for CS-supplemented calves compared with unsupplemented calves. No interaction ( > 0.05) was detected between the physical form of starter and CS provision with respect to the rumen fermentation parameters and body measurements. Total rumen VFA concentration and the molar proportion of propionate were greater ( < 0.01) in calves fed TS compared with MS-fed calves. In conclusion, independent of the physical form of starter, inclusion of 15% CS in starter diets improves the performance of dairy calves.