With grazed grass now making up 80-100% of the diet for most herds, changes to sward composition can have a large effect on milk solids output, according to Teagasc.

Teagasc research conducted across 40 client farms has demonstrated that high grass digestibility and reduced grass fibre (NDF) content are the most important nutritional factors for achieving high milk protein during mid-season.

In its latest newsletter Teagasc outline that a dietary fibre level of 33-35% NDF is important for good rumen function. This is readily met by good intakes of high-quality grass grazed at 1,300-1,400kg DM cover (3-leaf stage). On the other hand, it says grazing heavy covers of stemmy grass puts too much NDF in the diet, causing: decreased total dry matter intake due to slow-down of digestion rates; lower energy content per kg of feed eaten; and, reduced milk yield and milk protein content.

Teagasc advise where grass growth is outstripping demand keep control of the diet quality by setting pre-grazing grass yield to 1400kg DM and removing heavy covers as surplus bales. Use the grass wedge to make these decisions. It says where grass deficits arise, supplement with a high UFL, low protein ration containing digestible fibre (pulps), to hold rotation length and maintain intake. High quality bales saved during high growth periods can be used very effectively here.