Submitted to: International Silage Conference
Publication Type: Abstract Only
Publication Acceptance Date: 9/11/1996
Publication Date: N/A
Citation: Interpretive Summary:
Technical Abstract: The shift toward low cost silos is causing farmers to ensile alfalfa at lower DM contents, increasing the possibility of a poor fermentation. At the same time, seed companies are producing varieties with improved quality, which may also make ensiling more difficult. The objective of this study was to determine if alfalfa lines bred for high quality were more difficult to ensile. Eight alfalfa genotypes were established in 8 replicate plots of each in a randomized block design. Four plots were harvested for ensiling at early bud, and the remainder at first flower. In July, second regrowth was harvested from the first four plots at early bud, and first regrowth was harvested at first flower from the second set of plots. In all harvests, alfalfa was wilted to 35% DM, chopped in a stationary chopper, inoculated with lactic acid and ensiled, two silos per plot. Silos were opened, and silages analyzed after 30 d ensiling. There were only a few interactions between genotype and cutting or maturity in the characteristics of either the initial forage or the silages. Thus, differences among genotypes were generally similar across all 4 harvests. The high quality lines were 3 to 4 units higher in crude protein and 3 to 4 units lower in NDF than the standard lines. In contrast, buffering capacity was not significantly different across the genotypes. In the silages, pH, ammonia N, lactic and acetic acids were significantly different across the 8 genotypes. However, the differences were small from a practical perspective (e.g., an average pH range of 4.97 to 5.15), and the high quality lines did not consistently have the poorest fermentation characteristics. These results suggest that present efforts in breeding for high quality are not having a substantial negative effect on ensiling.