Chemical Composition of Ensiled Materials and Silage Quality : I. The Effect of harvesting time, moisture content, storage temperature and storage period on silage quality

1. We have been studying the feeding system of roughage mainly by whole year utilization of silage in daily farm since 1961. As the results, we found that the feeding system demanded the technique for silage producton of good quality and stability. This experiment was conducted to find the mutual effects of several factors on silage quality about autumn seeded Italian ryegrass that was harvested within the year, April and June. The conducted factors were moisture content (controlled by wilting), storage temperature and storage period. 2. Chemical composition of ensiled materials ; The order of moisture content was April>June>within year, and all materials contained more than 80%. The order of water soluble carbohydrate content was within year>April>June, and there were sever difference among the time of harvesting. The order of crude protein content was the same as that of water soluble carbohydrate content, but all materials contained same as or more than 20%. In accordance with wilting, crude protein content was a little change but water soluble carbohydrate content was decreased apparently. 3. The mutual effects of each factor on silage quality were summerized as follow ; i. The mutual effect of moisture contents in ensiled materials and storage periods ; In unwilting silage, silage harvested within year didn't change to low quality as period progresses, but silages harvested April and June changed to low quality. The change of silage quality as period progresses was consistent with water soluble carbohydrate content in ensiled materials. The wilting inhibited VFA production but for lactic acid production is promoted or inhibited according to circumstances. ii. The mutual effect of moisture contents in ensiled materials and storage temperatures ; In unwilting silage, silage harvested within year didn't change to low quality as heightening temperature, but silage harvested April and June changed to low quality. All wilting silages didn't change to low quality either. iii. The mutral effect of storage temperatures and storage periods ; There was few mutual effect of these two factors. Silage quality had a tendency to show additional change in oder of high temperature or long period. It is seemed that within the range of this experiment (from 15 to 30 degree C) heightening storage period, in other word, storage temperature have the effect of the fermentation rate rather than the silage quality. 4. Comparison with silage quality among times of harvesting ; In unwilting silage, water soluble carbohydrate content in ensiled materials was consistent with silage quality, and the disparity in silage quality increased with lenghtening period. In wilting silage, about 60% moisture content, all silages were good quality, but there were difference in production of organic acid among times of harvesting, so that it was seemed that the type of fermentation was different in wilting silage too.