12 May 1995

Do they add to your profit?

Hillsborough is respected for its work on silage additives. Rebecca Austin hears from researcher Dr Tim Keady how different types shape up

HALF of the silage in Northern Ireland is additive-treated each year, at a cost of £6m, with 60 different products jostling for a share of the spend.

But Dr Tim Keady from the Provinces Hillsborough Agricul-tural Research Institute insists the only true measure of their value is scientifically proven ability to improve animal performance.

By Dr Keadys yardstick of improved livestock performance, Hillsborough trials suggest formic acid is the best additive for use in difficult silaging conditions. Otherwise an effective inoculant is the best option. Sulphuric acid, molasses, enzymes and beet pulp increase silage fermentation but do not necessarily stimulate output.

Formic acid is an organic acid applied at 2.3-2.5 litres/t of herbage ensiled. But treatment with formic acid is unlikely to lead to an economic response, in terms of increased performance, under conditions in which the untreated silage preserves well.

"But under conditions where it improves fermentation relative to poorly preserved, untreated silage there is a substantial volume of evidence from Hillsborough and elsewhere to indicate increased silage intake, digestibility and animal performance of lactating dairy cows and finishing beef cattle."

Dr Tim Keady… In tricky conditions opt for a formic acid silage additive.