In Vitro and In Vivo Analyses of Hays of Switchgrass Strains Selected for High and Low In Vitro Dry

In a previous report the progress made in altering the in vitro dry matter digestibility (lVDMD) of switchgrass (Panicum oir-gatum L.) in one cycle of divergent selection was described. In this study, the detergent system of analyses was used in an at-tempt to determine what plant constituents had been altered by the selection for IVDMD. Hays from five switchgrass strains differing in IVDMD harvested over a 3-year period were ana-lyzed for protein content, neutral detergent fiber (NDF), acid detergent fiber (ADF), ash, and lignin. Although there were dif-ferences (p:s 0.05) among strains for IVDMD as determined by two different procedures (with and without additional N), there were no differences among strains for ADF, ash, lignin, and protein. The strains ranked the same with the two IVDMD procedures but the IVDMD·N (with additional N) test average