Effects of the feeding sequence of concentrate and forage and the feeding ratio of sake cake to grass hay on the characteristics and the entrapment effect of the ruminal mat in non-lactating dairy cows.

The effects of the feeding sequence of concentrate and forage, and of the feeding ratio of sake cake (SC) to grass hay (GH) on the ruminal mat characteristics and the entrapment effect for steamed flaked corn (SFC) by the mat were evaluated. Three non-lactating, rumen-cannulated Holstein cows were offered SC and GH using a ratio of 35:65 (SC35) or 65:35 (SC65). For SC35, SFC was fed at 1 h after or immediately before offering SC and GH, while for SC65, SFC was only fed at 1 h after. To estimate the degree of SFC entrapment in the ruminal mat, the location of SFC in the rumen and two types of mean retention time (MRT) were measured, that is, MRT for the SFC marker placed directly on the mat or taken orally. The ruminal mat was formed even when SC65 diet was consumed. The entrapment effect was not affected by the feeding sequence or the ratio. However, a more interesting finding is that the entrapment effect of the ruminal mat may not be as absolute as previously considered because of the large amount of SFC particles which precipitated at the bottom of the rumen 1 h after feeding.