Characteristics and Quality of Wrapped Big Bale Silage under Various Conserving Condition

Abstract

The harvesting system for making rolled big bale silage by wrapping has been prevailing rapidly in Japan. It is pointed, however, that the quality of the wrapped silage is unstable. This study was carried out to clear the characteristics of wrapped silage and to investigate the conditions for processing high quality silage. 1. Using five grasses ; Italian ryegrass (Lolium multiflorum Lam.), Sudangrass (Sorghum sudaense (Piper) Stapf.), guineagrass (Panicum maximumJacq. Var. maximum ), Rhodesgrass (Chloris gayana Kunth.) and grass mixtures, the relations between moisture content of raw materials and mean dry matter density of rolled bale were investigated. Further, changes of moisture distribution and dry matter density in wrapped roll bales were traced by using a trial sampler of silage. 2. Temperature in the middle of roll bale immediately after wrapping was markedly increased by delay of wrapping. Although temperatures in the surface of wrapped roll bale were varied with the colores of stretched plastic film, they were supposed not to affect so much the quality of silage. Besides, moisture content of raw materials, bale density and breakage of wrapping film affected temperature of the roll bale silage. 3. Four plastic film layers( 50% overwrapping) seemed to be sufficient to store for short term of two or three months, but in long term storage like one year, silage quality was degraded even by six film layers. Two film layers were enough to prevent heat damage of high moisture baled hay. 4. Processing of wrapped roll bale can be applied to wide moisture ranges of raw materials ; unwilted direct-cut grasses to low moisture grasses almost close to hay. It seems, however, to be advantageous to prewilt the materials as much as possible from quality and economical point of view. Simultaneously, it is necessary to increase roll bale density.