Main content area

Ammonia fiber expansion (AFEX) treatment of eleven different forages: Improvements to fiber digestibility in vitro

Bals, Bryan, Murnen, Hannah, Allen, Michael, Dale, Bruce
Animal feed science and technology 2010 v.155 no.2-4 pp. 147-155
ruminants, forage, energy crops, biofuels, Panicum virgatum, corn stover, fiber content, dietary fiber, pretreatment, chemical treatment, ammonia, heat treatment, pressure treatment, new methods, forage quality, in vitro digestibility, rumen fluids, rumen fermentation, degradation, neutral detergent fiber, nutrient content, crude protein
With the increased attention to bioenergy and especially cellulosic ethanol, there are concerns regarding potential competition for available land between biofuels and feeds/foods. Ammonia fiber expansion (AFEX), a pretreatment process for cellulosic ethanol, may also be used to improve ruminant digestibility of feedstuffs not traditionally used as forages. Eleven forages - including traditional forages, agricultural residues, and dedicated energy crops - were AFEX treated and digested in vitro with rumen inoculum. AFEX treatment improved 48-h neutral detergent fiber (aNDFom) digestion for several moderately indigestible forages compared to untreated samples, but showed no improvement for highly digestible samples. Of particular interest are corn stover and late-harvest switchgrass, as AFEX treatment improved digestibility by 52% and 128% over untreated material, whereas the improvement was 74% and 70% over conventional ammonia treatment, respectively. The crude protein content of all treated samples increased to more than 100g/kg dry forage. This research strongly suggests that AFEX-treated feedstuffs can be competitive with traditional forages, and thus offer expanded options for ruminant feeding.