Feed characteristics of dried corn grain and corn grain silage produced in Japan compared with imported corn grain.

We compared the in situ dry matter degradability (ISDMD) and crude protein degradability (ISCPD) of high-moisture corn grain silage and dried corn grains produced in Japan (JHC and JDC, respectively) with corn grains imported from the United States (USC), Brazil (BRC), and South Africa (SAC). The ISDMD values of USC, BAC, and SAC were between those of JHC and JDC, but ISDMD did not differ significantly between USC and SAC. In contrast, ISDMD was lower for BAC than USC and SAC. Overall, our results indicate that ISDMD and ISCPD in the rumen differ between corn grains sources (domestic compared with imported and between production locations), primarily due to differences between the corn varieties represented. In particular, the ISDMD and ISCPD of JHC were greater than those of JDC, and this difference in degradability needs to be considered when using high-moisture corn grain silage as a substitute for dried corn grain as a feed for dairy cattle.