In Experiment 1, three systems of milk production with contrasting calving patterns, namely 100% autumn (A); 100% spring (S) and 50% autumn: 50% spring (AS), were compared over a two year period. The average milk yield was 6,532, 6,358 and 6,142 kg/cow for systems A, AS and S respectively. The difference in yield was not statistically significant. Fat yield, fat content and protein yield for system S was significantly lower than those with the other two systems. The autumn-calving cows (A) had reduced reproductive performance. Experiment 2 compared grazed grass with grass silage as a forage source for autumn-calving cows in early lactation; it showed that the cows on grazed grass had significantly higher milk protein yield and milk protein content. The cows on the grass silage had significantly lower dry matter intake and a significantly higher bodyweight loss post-calving. The aim of this project was to develop low-cost systems of milk production which lead to an improved milk supply pattern of quality milk for the food industry. In particular, the objective was to research the role which grazed grass can contribute to the feed requirements of cows calving at different times during the year.