Dairy producers could improve yields by up to 4.4% by applying an additive to grass silage this season, according to findings from a trial carried out at Imperial College, Wye.

Two grass silages were taken from a third-year grass ley and half the forage was treated with Volac Agros silage additive at a rate of 2 litres/t. The rest acted as a control, says Volac’s Philip Jones.

While intakes of both silages were relatively high at 16.25kg DM a day, there was no significant difference in intake between the treated and untreated.

But cows fed the treated silage yielded an average 1.3 litres a day more than those fed the untreated. This yield improvement works out at an extra margin of more than £56 or an investment return of 6.6:1.