Effect of harvesting stage and acidity and microbial processing on degradability characteristics of sorghum silage using gas production method

This experiment was conducted to investigate the effect of harvesting, addition of formic acid and ruminal fluid to sorghum silage on amount of gas production. Sorghum at the first and second harvesting (with 25 % DM) was treated with formic acid and rumen fluid and then was ensiled for 81 days. After opening and drying the samples, a sample was taken from each treatment and put it into gas production syringe. Gas production at 2, 4, 6, 8, 16, 24, 48, 72 and 96 hours of incubation were recorded. Results showed that for the second-cut silage gas production was lower and that coefficient b was higher as compared to the first-cut silage. In the second experiment, gas production for the silage treated with ruminal fluid was significantly lower than the control treatment and a higher b coefficient was also found for the formic acid treated silage. Organic matter digestibility (OMD) and metabolism energy (ME) were greater for the first-cut as compared to the second-cut silage. Treating the silage with ruminal fluid caused a significant decrease of OMD (45.73 % vs. 52.1 and 52.59 %), ME (6.72 MJ/kg DM vs. 7.7 and 7.75 MJ/kg DM) as compared with formic acid and control treatments.