Effects of Maturity on Chemical Composition and Digestibility of Bird Resistant Sorghum Plants When Fed to Sheep as Silages

ALTHOUGH corn has provided the base crop both as a grain and silage source for the ruminant livestock industry in the midwest, diseases and severe predations by birds in some areas have forced a search for substitute crops of similar nutritive value. Grain sorghums offer yield potentials similar to corn, possibly greater drought resistance and greater latitude of soil fertility. High grain producing varieties of sorghums have recently been developed which are resistant to bird damage at least in the milk and dough stages due to high tannin content in the seed pericarp (Fuller, Potter and Brown, 1966; Harris, Johnson and Stacy, 1964). Recent studies at this research center 4 have shown that 100% of a non bird resistant variety was destroyed while five bird resistant varieties of sorghum were undamaged. Bird resistant sorghums have been fed to cattle with no apparent problems (Davies and Stallcup, 1966; Merwine, 1961). Fox et al. (1970) found, however, that the net energy value and digestibilities of AKS 614 bird resistant sorghum were considerably less than those values for corn, both when fed as a grain and a silage to beef cattle. They found that the sorghum grain at late maturity was highly resistant to digestion unless the hull was broken by grinding.