ANÁLISIS QUÍMICO Y DIGESTIBILIDAD "IN VITRO" DE RASTROJO DE MAÍZ (Zea mays L.) 1

Chemical analysis and in vitro digestibility of corn stover (Zea mays L). This experiment was conducted to evaluate the effects of chemical and physical treatments on the chemical composition and in vitro dry matter (IVDMD) and organic matter (IVOMD) digestibility of corn stover. Seventy five bales of corn stover (25 ground, 25 chopped, and 25 whole) were treated with 4% ammonia (NH3) of the dry matter weight. A completely randomized design with factorial array 2x3 (0.0 and 4.0% NH3 and three particle sizes). Results indicated that dry matter content decreased as particle size increased. Protein content increased by 110, 116 and 91 units for the ground, chopped and whole corn stover treated with NH3 with respect to the control. Ether extract increased by 7.3% for corn stover treated with NH3. Similar trend was followed by the ash content which increased by 6.0% for corn stover treated with NH 3 . Ammonia treatment affected negatively the neutral detergent fiber values by 20.0, 7.0 and 7.7% for ground, chopped and whole corn stover, respectively. Similar results were found for acid detergent fiber with values of 7.17, 12.53 and 11.42% lower for ground, chopped and whole corn stover, respectively; than those found for the untreated material. IVDMD and IVOMD were increased with NH3 treatment.