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.

Documented data comparing both cutting and grazing grass growth rates in Ireland are minimal. Most protocols for measuring grass growth involve a cutting regime of either 3 or 4-week cycles. The effect of the grazing animal is absent in most situations. However, herbage production can readily be affected by the rate of fertiliser nitrogen used and the frequency of grazing/cutting management 6 practices employed. The first two experiments reported here were undertaken to assess grass growth under grazing and cutting regimes and to determine the extent of differences which may arise from different harvesting procotols. The third experiment investigated the effect of nitrogen application rate and regrowth interval on annual herbage production. Early grazing: The experiments reported here were conducted to examine the effects of early turnout to grass on beef cattle production and on sward productivity. Autumn pasture production: The present series of experiments investigated the effects of autumn closing dates on herbage yield and quality as well as their effects on sward productivity. The effects of short and long grazing rest intervals were evaluated in the context of autumn grass growth and their effects on subsequent spring growth.

The objectives of the project were to compare different cultivar types and methods to establish and maintain them in reseeded and permanent pastures as a basis for efficient low cost sheep production. In Ireland only 3% of pastures are reseeded annually and permanent pastures rarely contain more than 5% white clover. Improved clover content offers benefits of higher lamb growth rate and reduced fertiliser N use. Comparisons under cutting conditions provided no basis for replacement of Grasslands Huia by the new cultivar Aberherald. Grasslands Huia established successfully following direct reseeding and rotational grazing by sheep. It established more quickly than Kentish and gave higher yield only in the first year. A mixture of small and medium size white clovers should be sown for sheep grazing. Increasing seeding rate from 2 to 4 kg per ha increased pasture clover content only in the first year. Grasslands Huia persisted quite well for up to 5 years under rotational sheep grazing. It also survived under continuous grazing but leaf size was reduced. Rotational grazing management with sheep increased the clover content of permanent pasture from under 2% to 4% over 2 years. Highest clover yields were achieved with rest intervals of 20 to 28 days. Simulated mixed sheep and cattle rotational grazing on permanent pasture resulted in intermediate (10 to 12%) clover dry matter contributions to total dry matter compared with cattle (15 to 18%) and sheep (5 to 8%). Lamb growth rate was about 35% higher when the clover content of the sward was increased from very low to about 35%.