Nutrient and microstructural indices of maize and sorghum responses to ammonia pressurization/depressurization

A pressurized ammonia (NH3) technique (TAME) to enhance nutrient availability from maize and sorghum for cattle feeds was investigated. Treatment conditions evaluated were NH3 loading rate and temperature. Starch, enzyme susceptible starch, in vitro dry matter digestibility (IVDMD), in situ (ISDMD) dry matter digestibility, and structure were determined. Grain treated at 50 degrees C or higher temperatures exhibited popped characteristics and had no intact starch granules. Enzyme susceptible starch was 3.6- and 4.6-fold higher than controls in treated maize and sorghum. The IVDMD increased above control maize (87.8 +/- 2.3%) and sorghum (80.0 +/-0.65%) with all NH3 levels, and it averaged 91.5 +/-1.9% for maize and 87.8 +/- 1.0% for sorghum. At 12 and ISDMD was at least 31.8 and 9.3% higher than controls in treated respectively, and 52.9 and 46.6% higher in treated sorghum, respectively. This is the first process to make sorghum more valuable than maize as an energy/protein feedstuff in cattle diets. Because TAME treatment increased ISDMD and rate of digestion, this procedure is expected to increase total nutrient availability from these grains in common beef cattle diets