'Seriously fast' grass

Growing grass mixtures purely for cutting can provide tonnes of top class silage in no time at all.

The grass has kept growing, albeit slowly, in many places across the UK during the mild winter. Some herds have already been out grazing for a month and the signs are looking good for early first cuts of silage.

Perhaps 2016 will be the year to reverse the declining trend of milk from forage figures, which have hovered around the 2,500 litres/cow/year for the past decade; but down to 2,266 litres/cow in 2015. Regardless of system, farmers should be aiming to produce 4,000 litres /cow from forage every year.

For silage, yield is the overriding consideration. Maximum output will come from young leys filled with new varieties that have been bred specifically to produce large crops of highly nutritious herbage.

“Grass silage is more expensive than grazed grass to feed, but it is still more than half the price of an 18% concentrate feed,” says Rod Bonshor, general manager for Oliver Seeds.

“Short-term silage leys can deliver 37t DM/ha/year over two years, compared to perhaps 30t DM/ha/two years for longer term, dual purpose swards. That is a lot of extra expensive cake to buy to make up the shortfall in energy and protein.”

Big yielding species
Westerwold is an annual ryegrass, which is fast to establish, producing forage within eight to ten weeks of seeding. It is the only grass to produce a stem and seed-head from a spring sowing and should be cut before it heads, to encourage regrowth for second or subsequent cuts.

Westerwold ryegrass makes excellent silage and has higher sugar levels than perennial ryegrass, which aids fermentation. It is also leafy and palatable and can provide useful early-bite grazing.

“Mixtures of westerwold and Italian ryegrasses as in Tornado, have to be managed carefully,” says Mr. Bonshor. “Their relatively open nature calls for regular cutting or rotational grazing to gain full yield potential. Trials show that an extra £148 worth of silage can be produced in just six months, based on gaining an additional 3.7 tonnes of 25% dry matter silage priced at £40 per tonne.

“While cash flow is tight, putting in a short-term westerwold-based ley costing £2.35/kg, compared to a longer term perennial ryegrass at £4.10/kg, might be a more cost-effective solution for boosting grass yields for this year and next.”

Seed rates are typically 14kg/acre (35kg/ha). Drillings made in open autumns can become taller than ideal to go through winter, and youngstock or sheep can be used to graze it down to 10-15cm (4-6 inches). Spring-sown swards drilled in the first week of March may be ready for cutting by mid May.

To achieve the highest yields, westerwold mixtures need feeding – up to 300kg/ha of nitrogen (N) per year, with added phosphate (P) and potash (K) where soil indices are inadequate.

“Twenty years ago there was little interest in westerwolds and the available varieties were of poor persistence and quality. But this is now changing.

“There is currently no recommended list for westerwold varieties in the UK. We cross-reference independent data from France and Germany with plots we grow at our trials ground in Gloucestershire – so we know the ones in our mixtures will do well in UK conditions.”

This article first appeared in COW MANAGEMENT March 2016