The digestibility of corn silage harvested at four stages of maturity as determined by in vivo and in vitro methods

Recently, in the Southeast there has been a great increase in beef cattle production. Until now, most of this has been in the form of "weanlings" which were shipped to the Midwest and other areas for growing and fattening. Although there has been an increase in the finishing of beef cattle in this area, much more beef is consumed than is produced and meat has to be shipped in from elsewhere to meet the growing demands. Therefore, an increased income potential from the growing and fattening of beef exists in this area. However, the Southeast cannot compete with the Midwest in the feeding of grain since most of the grain has to be shipped in which tends to make it unprofitable to feed. Because of this, beef cattle in the Southeast are grown and fattened mainly with forages of which a great proportion is corn silage. Corn silage has been used as a feed for ruminants for a long time and has proved to be a highly palatable and economical source of energy. At present, there is an even greater interest in the feeding value of silage, mainly due to new high yielding corn varieties, modern fertilizing practices and the addition of additives such as urea, which can increase its nutritive value still further. In spite of these major advancements, very little experimental work has been performed to determine the effect of harvesting time of corn silage on its digestibility. Therefore, the major objective of this investigation was to compare the digestibility of corn silage harvested at the very early dent, early dent, dent and late dent stages of maturity by the use of in vivo and in vitro digestibility techniques. The secondary objective was to determine, by the use of an in vitro fermentation technique, how the digestibility of various silage components (stalks, leaves, cobs or kernels) is affected by differences in corn plant maturity.