Effect of chemical additive and packing method on prevention of secondary fermentation of corn silage

Study aimed to prevent secondary fermentation after corn silage was discovered from silo for transportation. Exp. I corn silage has been subjected to 5 groups, i.e. Group 1 without additive, Group 2-5 mixed with formalin or formic plus formalin (1:3) at 5 or 10 g/kg fresh matter. The silage was repacked in transparent plastic bags, 15 kg each, in 5 replicates (total 25 bags). Temperature inside the bags and weight of the bags were recorded daily. pH and organic acids were determined. Exp. II was conducted to observe acceptability of ruminants. Corn silage was repacked in bags, each contained 15 kg Treatment 1, the packing was done with vacuum in transparent plastic bags without additives. Treatment 2, the material was supplemented with formalin 10 g/kg fresh matter and repacked in 1 layer polyethylene (PE) bags without vacuum, stored for 3 days. Treatment 3 as Treatment 2 but stored for 6 days. They were fed to 6 male Merino crossbred sheep average BW 22.87+-1.51 kg. The silage was supplemented with concentrate at 66:34, 46:54 and 60:40 respectively. Voluntary dry matter intake was recorded. Exp. III was conducted to observe packing method on preventing secondary fermentation. Group I, the silage was repacked without additives in double layer PE bags with vacuum suction. Group II, the silage was mixed with formalin at 3.3 g/kg fresh silage and being packed in single layer PE bags without vacuum suction. Group III, packing was done as group I, but the silage was mixed with formalin at 1.7 g/kg fresh weight. Temperature in the bags and bags weight were recorded daily. The result revealed that addition of formalin at 10 g/kg fresh weight gave the best result due to the lower dry matter loss, lower pH, higher lactic acid, better quality silage and no temperature rise during 8 days, while the unsupplemented group had high temperature on the first day. However, this rate of formalin (10 g/kg fresh matter) caused low palatability and acceptability of animals. Secondary fermentation could be prevented by packing silage in double layer PE bags in an airtight condition. Formalin was not necessary.