摘要：The objective of present study was to evaluate the chemical composition , crude protein fractions and in situ ruminal digestibility of Maize Silages (MS) produced in Isfahan. The MS samples were taken from bunker silos from 20 farms across Isfahan province. The crude protein was fractionated based on the Cornell Net Carbohydrate and Protein Model. Ruminal digestion kinetics of Dry Matter (DM) was assessed using two ruminally fistulated Naeini rams. Chemical compositions were analyzed in a completely randomized design. Degradability data were analyzed in a randomized complete block design and means were compared using Duncan’s test. Results revealed a lower DM (23.4 vs. 28-32%), lower nonfiber carbohydrates (24.5 vs.>30-35%), lower effective ruminal degradation of DM (EDDM, 48.4 vs.>55%), higher neutral detergent fiber (NDF, 58.5 vs.<50-52%) and higher acid detergent fiber (35 vs.<30%) than the optimum ranges. Regression analysis demonstrated a strong negative relationship between EDDM and NDF content of MS. The harvest of Maize Crop (MC) at a greater DM content than 24-28% when the kernels are more developed is suggested to maximize benefits from the current progressive growth in MC production in Iran. Wilting the MC to increase its DM content could be an alternative, when short day-length or unpredictable climate do not allow for a timely MC harvest.
