NUTRITIVE POTENTIAL OF MULTITILLERING CORN COMPARED WITH NONTILLERING CORN FOR SILAGE

Corn (Zea mays L.) hybrids have been bred primarily for grain production. Generally the ideal corn plant is considered to be one with a single stalk and a grain-to-stalk ratio approaching 1: 1 (Matsushima 1971; Nich olson 1971). For many years grain hybrids have been recommended for ensiling (White et al. 1924; Nevens 1933; Matsushima 1971) on the assumption that grain content in silage is the main factor determining the energy value for feeding livestock. The validity of this assumption was questioned by Hemken et al. (1971) when they found no significant differences in digestibility or milk production in cattle fed corn hybrids with highly different grain-to-stalk ratios. They concluded that corn hybrids for silage should be selected on the basis of dry mat ter yield rather than grain content. Recently a number of experimental multi tillering corn hybrids have been developed at the Canada Department of Agriculture Research Station, Ottawa, Ontario. These hybrids are capable, under irrigated condi tions in western Canada, of yielding more dry matter than the recommended single stalked plants. One of the Ottawa hybrids has been licensed as Stewarts Multi-T and is now available to growers. Multitillering hybrids have a low grain to-stalk ratio. Consequently, the question arises as to how they compare in nutritional quality to single-stalked plants. A study was conducted in 1971 to compare some of the factors that contribute to the nutritional potential of silage of these two types of hybrid corn. An attempt was also made to determine whether differences existed in the nature of fiber in the stover. Hybrids of the two types of corn were grown in silage yield trials at Taber, Medi cine Hat, and Lethbridge in southern Al berta. At Taber and Medicine Hat a non tillering hybrid (Idahybrid 216) and four tillering (OX403, 404, 383, and 377) hy brids were grown in rows 10 m long and 75 cm wide. The corn was harvested in the well-dented stage with a forage harvester. A 5-kg sample of the chopped material was removed from each row and was dried and