Researchers at the University of Illinois are working to perfect an edible-covering system for silage.

Last year, the research team, led by Larry Berger, professor of animal science, filled four mini-bunkers with the same amount — 8,000 pounds — of corn silage. They covered one bunker with black plastic and sprayed the other three with an edible covering made of salt, ground wheat and tap water. They sealed the edible cover with one of three wax coatings: a spray-on wax emulsion, paraffin wax, or food-grade wax paper like that used to wrap meat. Four months later, the researchers opened the bunkers.

The results show the paraffin wax preserved the silage better than any of the other treatments, as indicated by the larger amount of dry matter fed from that bunker. Here are the results for all four bunkers:

Treatment Pounds of dry matter fed

Paraffin wax 5,861

Wax paper 5,493

Black plastic 4,759

Wax emulsion 4,378

The wax emulsion did not perform as well as the other wax coatings because it was too runny, Berger says.

A commercial product could hit the market in two years. However, more work is needed to perfect the edible-cover and wax-coating application process.