Rise in dried grains supply for use as animal feeds due to increased global production of biofuels

Due to increased global production of biofuels, there is a greater supply of associated protein-rich by-products such as distillers dried grains available for use as animal feed.

These have been evaluated by Teagasc researchers at the Grange centre in Co Meath.

They compared intakes and performance of beef cattle offered a barley based ration with increasing levels of inclusion of dried maize or wheat distillers grains as a supplement to grass silage and, subsequently, fed to appetite.

The nine concentrates assessed were either:

a barley-soya ration (862g/kg rolled barley, 60g/kg soya bean meal, 50g/kg molasses and 28g/kg minerals/vitamins). This ration contained 137g crude protein/kg of dry matter;

or barley-soya based rations where the barley (plus all soya bean meal) was replaced with 200, 400, 600 and 800g fresh weight of maize dried distillers or wheat dried distillers grains/kg.

The crude protein concentration ranged from 149 to 248g/kg in the maize dried distillers rations, and from 154 to 270g/kg in the wheat dried distillers rations.

Steers were individually offered 3kg (dry matter) of the respective concentrates as a supplement to moderate digestibility grass silage offered to appetite over a 70-day growing phase.

After a 26-day dietary adaptation period, they were offered the same concentrates ad lib, plus 3kg fresh weight of grass silage daily, during an 86-day finishing phase.

Rating the barley-soya ration at 100, results showed that maize dried distillers grains had a superior feeding value (111) to wheat dried distillers, both during the growing and finishing phases.

When offered as a supplement to grass silage, both maize and wheat dried distillers grains had a superior feeding value compared to the barley-soya ration, with highest values obtained at the 800g/kg inclusion level.

In contrast, when the concentrate was offered to appetite, maize distillers had a fairly comparable feeding value (99% to 95% across all inclusion levels), whereas the feeding value of wheat distillers ranged from 107% to 80%, compared to the control ration.

Under the conditions of this study, results indicated that the optimal inclusion level of dried distillers grains in the concentrate was about 800g/kg when offered as a supplement to grass silage, and about 200g/kg when offered to appetite.