High rates of decline in milk yield of >3.0% /week are common when dairy cows are grazing due to low herbage intakes. Under indoor feeding conditions rates of decline are often <2.0% /week. Behavioural factors control intake at grass, in particular the time spent grazing and the rate of intake. Low intakes produce high rates of decline in milk yield and potentially could lead to problems of poor fertility and welfare in high merit cows. The objective of this research is to examine the replacement of time available for grazing with time made available for eating forage-based diets indoors. This experiment was carried out in the spring.