Effects of rice conservation methods on lactation, blood metabolites, and rumen fermentation in dairy cows

We investigated the effect of rice grain conservation methods on feed intake, milk production, blood metabolites, and rumen fermentation in dairy cows. Raw rice grain was dried before crushing (DRY), ensiled after crushing (ENS-A), or ensiled before crushing (ENS-B). Twelve multiparous Holstein cows were used in a replicated 3 × 3 Latin square design with three dietary treatments comprising ad libitum access to one of three total mixed rations (TMRs; containing DRY, ENS-A, or ENS-B at 17% of dietary dry matter) plus a standard allowance of 2.0 kg/day of dairy concentrates. The dietary treatments did not affect the feed intake, milk yield, or milk composition. The selected blood constituents were not influenced by the rice conservation method. The ruminal lactic acid and total volatile fatty acid (VFA) concentrations and the VFA proportion in the cows were not influenced by the rice conservation method. These results demonstrate that the rice grain conservation method has little impact on lactation performance when cows are fed a TMR containing 17% treated rice grain (dry matter basis).