Methods of testing grass varieties are discussed and the efifects of differences in management and of nitrogen fertilizer on quality are shown. In a grazing‐management system with 9 cuts per season, cocksfoot was higher than perennial ryegrass in protein and fibre and lower in soluble‐carbohydrate content andin vitrodry‐matter digestibility throughout the season. All species showed the lowest value for digestibility in August.Curves for digestibility in primary growth were plotted for 4 varieties of ryegrass for leaf and stem fractions. The tetraploid variety Reveille was slightly more digestible than S24 in leaf and stem throughout the period, while at ear emergence S23 was lower in digestibility in both fractions than S24.There were significant differenees in composition and digestibility between experimental centres, but relative differences between varieties were consistent. The level of N fertilizer did not materially alter the comparison between varieties in quality