Viability of Echinochloa crus-galli (L.) Beauv. and Digitaria adscendens (H.B.K.) Henr. seed excreted in feces from cattle

When hay is contaminated by many seeds of Echinochloa crus-galli (L.) Beauv. and Digitaria adscendens (H.B.K.) Henr., it is possible that these seeds disseminate over cultivation fields through the feces of cattle eating this hay. The purpose of this study is to estimate the number of seeds of both weeds in hay (Exp. 1), and to clarify which digestive organ affects the germination of the awakened and dormant seeds in vitro and in vivo (Exp. 2). The number of seeds of both weeds in hay increased as the coverage of both weeds increased. It was estimated that l0,000 seeds of both weeds were included in 1 kg of the hay from a meadow dominated by both weeds. Artificial rumen fluid alone did not affect the germination of both weeds, while acid-pepsin fluid depressed the germination largely. Awakened seeds of both weeds collected from cattle's feces showed slight germination. However, dormant seeds of D, adscendens germinated more than 20%, and those of E. crus-galli germinated to the same percentage as before being fed to the cattle. From the abovementioned results, it appears that a large number of germinable seeds were excreted into cattle's feces, especially in the case of dormant seeds.