Buffer feeding is a widely used strategy to improve DM intakes from dairy cows at grass. A very wide range of products have been used as buffer feeds resulting in a wide range of responses. Less well understood are which factors are important in explaining these responses. In this experiment the buffer feed characteristic “dry matter content” and the animal factor “stage of lactation” were used as variables in order to gain a better understanding of responses to buffer feeding.

Forty Friesian cows, of which 20 were spring calving and 20 autumn calving were used in a continuous design experiment lasting 5 weeks from 3 May until 7 June 1993. The animals were allocated to four treatments on basis of milk yield, liveweight and stage of lactation. The treatments were grazing only (C), grazing and a buffer feed at 30% DM (B30), 50% DM (B50) and 80% DM (B80) and for each treatment half the cows were spring calving (S) or autumn calving (A). The grazing consisted of a 8 ha field of predominantly perennial ryegrass which was split into 4 equal paddocks which were grazed on a daily rotational basis.