Japanese animal production is strongly dependent on imported feed (mainly grain); the feed self-sufficiency ratio for dairy cows is only 30% (Ministry of Agriculture, Forestry, & Fisheries, 2020). This method of agriculture in Japan does not seem to be sustainable, because a high dependence on foreign countries reduces flexibility for dairy farmers and increases the environmental impact of dairy production. Therefore, an interest in producing self-sufficient concentrate has begun to grow in Japan. For example, a feed rice (e.g., whole crop silage and soft grain silage) is used in various regions except for Hokkaido, and an ensiling grain and/or ear-leaf of corn (e.g., ear corn silage, high-moisture shelled corn, and corn cob mix) is used mainly in Hokkaido (Ministry of Agriculture, Forestry and Fisheries, 2020). Among these type of feed, the production of ear corn silage (ECS) has been growing in prevalence within TMR centers and contractor organizations in Hokkaido, since ECS has high nutritive value and fermentation qualities (Oshita, Nemoto, Aoki, Ueda, & Aoki, 2016; Otsu et al., 2012). Milk production from cows fed with ECS supplement in silage-based feeding was equal to that from cows fed with a flaked dry corn supplement (Aoki,