Summer annual warm-season grasses such as sudangrass or sorghum-sudangrass hybrids often have some late season value, but caution needs to be taken utilizing these forages this time of year.
Once frosted, these forages produce a cyanide containing compound commonly called prussic acid. It is the same compound that is produced by these same plants under stressed conditions, (such as drought) and is found in stressed Johnsongrass. Once frosted, this plant quickly starts shutting down and prussic acid is produced. Livestock should be removed from these forages for 10-14 days to allow for the forages to “dry down” and the prussic acid to dissipate before grazing again. Frosted sudangrass or sorghum-sudangrass hybrids can be harvested for balage right after being frosted and later fed as long as they are allowed their normal fermentation process time period of three or four weeks. Frosted areas could be only “pockets” in a field to start with. Any regrowth from the base of the plant after a frost can also be very high in prussic acid. If in doubt about nitrates or prussic acid – test before feeding or grazing!
Enjoy the nice fall weather and as always, keep on grazing!
Heart of America Grazing Conference – Jan. 20-21, 2014, Columbus
Southern Indiana Grazing Conference – Feb. 5, 2014, Odon – Jim Gerrish and Kathy Voth are main speakers.
Northern Indiana Grazing Conference – Feb. 7-8, 2014 — Michiana Event Center, Howe.
Stay tuned for more information along with other workshops and field days.