Under the conditions of our study, feeding forage SSreduced the DMI and milk yield of dairy cows whencompared with AS, likely because of an increased content of NDF and its reduced ruminal degradability.Despite the negative impact on ruminal fiber degradability, forage SS had no effect on ECM, milk efficiency,and total tract nutrient utilization. More research isneeded to determine the optimal stage of developmentat harvest and the long-term effects of feeding forageSS to dairy cows.