Feeding at Grass - North East Dairy Event

Published 7 June 13


May 2013

Jimmy Goldie, Senior Dairy Consultant at SRUC talks about feeding at grass.

Grazed grass is one of the cheapest feeds available for dairy cows especially this season. Maximising both the use of grass and milk production needs to be balanced to keep grass intakes up and at the same time providing the correct type and amount of nutrients. To optimise rumen function and maximise utilisation of grass, supplementation or buffering may be necessary. Good quality grass is high protein and low fibre. High protein grass requires a high energy supplement. Assuming good grass availability, a low protein, high starch or sugar source provides a good balance. Cereal or molasses type products, which are high in available energy and low in protein, are ideal supplements. This readily available energy allows the rumen to process the high rumen degradable protein from the grass. Without this source of energy the protein in the grass is wasted. Both cereals and molasses type products are low in fibre which means they have a low substitution rate allowing the cows to maximise their grass intakes. However, this may lead to lower butterfat levels. Higher fibre feeds may reduce the risk of acidosis and lower butterfat levels but they will have a highe substitution rate reducing grass intakes. A small amount of forage can be offered but beware it is not just replacing grass. Offering a high energy supplement can also be beneficial for cow condition especially in early lactation and should lead to better fertility.

If cows are housed at night, the feeds offered should still complement the grass available during the day. A lower forage TMR can be offered to maximise feed intakes from both grass and TMR. The forage portion of the mix must still be high quality to maximise nutrient supply and minimise substitution of grass. Due to the lack of carry over forage this season, TMR mixes may have to be formulated quite differently from previous years. Adding brewer grains or other similar products along with straw or hay and concentrates may make good TMRs but beware of keeping quality of these mixes as they will tend to overheat quickly especially if air temperatures are a bit higher. 

It is clear that grazed grass is the cheapest feed to produce milk. However, monitoring grass availability and the quality, cow condition and performance along with suitable supplementation is essential to ensure longer term nutrient balance is correct for rumen function, cow health and fertility.