NUTRIENT AND MICROSTRUCTURAL INDEXES OF MAIZE AND SORGHUM RESPONSES TO AMMONIA PRESSURIZATION DEPRESSURIZATION/

A pressurized ammonia (NH3) technique (TAME) to enhance nutrient avail ability from maize and sorghum for cattle feeds was investigated. Trea tment conditions evaluated were NH3 loading rate and temperature. Star ch, enzyme susceptible starch, in vitro dry matter digestibility (IVDM D), in situ (ISDMD) dry matter digestibility, and structure were deter mined. Grain treated at 50 degrees C or higher temperatures exhibited popped characteristics and had no intact starch granules. Enzyme susce ptible starch was 3.6- and 4.6-fold higher than controls in treated ma ize 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 9 1.5 +/- 1.9% for maize and 87.8 +/- 1.0% for sorghum. At 12 and 24 hr, ISDMD was at least 31.8 and 9.3% higher than controls in treated maiz e, respectively, and 52.9 and 46.6% higher in treated sorghum, respect ively. This is the first process to make sorghum more valuable than ma ize as an energy/protein feedstuff in cattle diets. Because TAME treat ment increased ISDMD and rate of digestion, this procedure is expected to increase total nutrient availability from these grains in common b eef cattle diets.