EVALUATION OF FEED VALUE, FERMENTATION CHARACTERISTICS AND MICROBIAL QUALITY OF GREEN MAIZE STOVER (Zea mays L.) AND ALFALFA (Medicago sativa L.) MIXED SILAGE

Abstract

This study was conducted with the objective of evaluating the physiochemical and fermentation characteristics, feed value and microbial quality of green maize stover (GMS) and alfalfa mixed silage. To meet the objective GMS and Alfalfa crops were cultivated and harvested in Arba Minch Agriculture Research Center. The maize grown was harvested at two the third of milk stage, while the alfalfa was harvested at about 50% of blooming stage. Then the harvested biomasses (GMS and Alfalfa) were chopped and wilted separately, and mixed proportionally in four levels of treatments (T) and five levels of replications. The treatments were: T1 (100% GMS), T2 (40% GMS + 60% Alfalfa), T3 (60% GMS + 40% Alfalfa) and T4 (80% GMS + 20% Alfalfa). After taking fresh samples for laboratory analysis, all the proportionally mixed treatments were ensiled anaerobically in a 4.5 kg capacity PVC tube micro silo for 60 days. The experiment was conducted by completely randomized design with a 4 × 2 (4 levels of treatments and 2 ensiling days) factorial arrangement. The results for cultivated GMS and Alfalfa forage during harvesting had 44,778 and 11,815 Kg/ha fresh biomass yield and 14,611 and 3,140 Kg/ha total dry matter yield respectively. The ensiled GMS and alfalfa mixed silage after 60 days of fermentation had a positive effect (P <0.05) on sensory evaluation, physiochemical characteristics, feeding value and microbial count with increasing the proportion of alfalfa from 20% to 60% in the mixture. The sensory evaluation revealed that light olive green color, pleasant smell, fairly firm texture and scattered mold spot in T1 and T4, whereas olive yellow color, almost pleasant smell and soft texture for T2 and T3 and medium with scattered mold spot in T2 and T3 respectively. The results obtained for T2 after fermentation was showed (P <0.05) better effect on Ash (11.79), CP (24.78), EE (7.95), DDM (64.46), DMI (2.93), RFV (145.5) and TDN (64.1) by decreasing GMS from 100% to 40% within the mixture. The results obtained for pH at 0 day were 5.14, 5.96, 5.76 and 5.49 for fresh sample, T1, T2, T3 and T4 respectively. The results obtained for pH at 60 days were 3.71, 4.09, 4.01 and 3.85 for T1, T2, T3 and T4 respectively. The results for microbial count revealed that at day 0 lowest values of TVC (5.79) and Enterobacteriacea (6.79) were recorded for T2 and Yeast and Mold counts (5.89) for T3 log cfu/g respectively. At 60 day, the highest count for TVC (6.05) were in T2, Yeast and Mold (4.31) for T1, and Both Enterobacteriacea and Yeast and mold counts were not detected for T2. It was concluded that, increasing the proportion of alfalfa at least 60% in the ensiling of GMS mixture had a significant (P <0.05) effect in chemical composition, physiochemical characteristics, feed digestibility and microbial count on fermentation quality and for nutrient preservation. Therefore, it should be better to ensile 40% of green maize stover with 60% of alfalfa to improve feed value and protein content of the fermented forage feed for animals.