8 May 1998

Is quality grass silage cost


HIGH feed value grass silage may well be a more expensive feed for dairy cows than cereals or by-products, depending on the individual production system, and land costs.

Researcher Sinclair Mayne of the Agricultural Research Institute of Northern Ireland, Hillsborough, delivered this message during a ruminant production seminar at the institute last week.

He urged producers to analyse the costs of making 1t of high quality grass, and to consider whether cereals or by-products may be more cost effective feed options.

"High quality grass silage is no longer a cheap feed given the high land prices and increasing costs of mechanisation, storage and feeding out," he said. Current trends towards more frequent cutting, use of expensive mower conditioners, and tedding equipment to allow rapid field wilting, and fine chopping by precision chop forage harvesters all contributed towards the increased cost of grass ensiled.

Dr Mayne has calculated silage costs a tonne DM either assuming a land cost of £247/ha (£100/acre) or no land charge (see Table 1). These show high quality three-cut silage costs an extra £19-20/t DM compared with two-cut material in a direct cut system. On an energy basis, costs of silage range from 0.77 to 0.86p/MJ ME, assuming a £247/ha land cost.

But while the cost of producing high feed value grass silage – which requires more frequent cutting – is increasing, cost of cereals and by-product feeds have fallen.

Table 2 shows comparable costs which could be justified for a range of cereal and by-product feeds relative to the energy cost of grass silage produced in a two- or three-cut system.

As Dr Mayne explained, citrus pulp, at £70/t and assuming £5/t on farm storage and feeding charge, worked out as 0.71p/MJ ME and is therefore, a cheaper energy source than either two- or three-cut grass silage based on a land rental charge of £247/ha.

If no value is attached to land in silage making costs, citrus pulp would need to decrease to £50-60/t to be competitive against two- and three-cut silage respectively, illustrating the effect of including a land value in silage making costs.

Medium quality two-cut silage is cheaper than higher value material, said Dr Mayne, but it may not be the answer to reducing costs. Although feed and forage costs are lower for the medium quality silage, savings in feed costs could be more than offset by increased fixed costs.

"Extra purchased feed will be required with a medium feed value silage to produce a given volume of milk. This may require additional investment in feed storage, handling and feeding systems, which may markedly increase fixed costs," explained Dr Mayne. Extra cows may be needed, increasing labour, housing and other capital costs.

Clearly, the best production system would depend on individual farm circumstances, he said.

Table 1: Silage production


Harvesting system

Direct cut Wilted

2-cut 3-cut 3-cut

Cost/t DM (£)

No land charge 52 71 67

Land charge 78 98 94

Cost/MJ ME (p)

No land charge 0.52 0.62 0.59

Land charge 0.77 0.86 0.8

Table 2: Energy values of a range of cereals, by- products

and dairy concentrates and relative value a tonne

Ingredient Effective ME Cost (£/t) delivered on farm to

(MJ/kg fresh) equate to grass silage cost

2-cut silage 3-cut silage

Barley 11.4 87.80 98.00

Wheat 11.4 87.80 98.00

Maize 13.3 102.40 114.40

Maize Gluten 10.9 83.90 93.70

Citrus Pulp 10.6 81.60 91.20

Sugar Beet Pulp 10.6 81.60 91.20

Dairy Concentrate 11.8 90.90 101.50

Sinclair Mayne:"Is high feed value grass cost-effective?"

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