The prevention of subclinical rumen acidosis (SARA) in high-producing dairy cows is the inclusion of a buffer in the mixed feed ration (TMR). The aim of the experiment was to find out whether straw in the TMR of dairy cows can replace the buffering capacity of sodium bicarbonate. 36 dairy cows were included in the experiment, divided into 2 groups, the experiment lasted 42 days, it was divided into 2 periods. In the 1st period, dairy cows of group A were given TMR K with 0.1 kg of sodium bicarbonate, in the 2nd period TMR P with 1 kg of wheat straw. Dairy cows in group B were fed in the 1st period of TMR P and in the 2nd period of TMR K. Straw in the TMR of dairy cows replaced the buffering capacity of sodium bicarbonate in the given doses and increased the fat content in milk. However, the transition from TMR K to P resulted in an increase in the time of eating.