The 2008 Joint Meeting of the Society for Range Management and the America Forage and Grassland Council. |
Thursday, January 31, 2008 - 9:40 AM
Preserving Water Soluble Carbohydrate in Hay and Silage
Dwight S. Fisher, J.P.C.S. Natural Resource Conservation Center, USDA-ARS, 1420 Experiment Station Road, Watkinsville, GA 30677 and Joseph C. Burns, Plant Science Research Unit, USDA-ARS, 1119 Williams Hall, Box 7620, North Carolina State University, Raleigh, NC 27695.
The water soluble carbohydrate (WSC) content of forage may be manipulated by harvest timing within a 24-hour period to take advantage of the diurnal cycle. However, increases in carbohydrate may be lost during the haymaking or ensiling process. Rapid drying and dry storage is necessary to prevent losses of WSC to respiration during and after conservation of forage as hay. Hay cuts made early (before 1200h) or on cloudy days may begin the drying process with reduced levels of WSC. In humid environments, rainfall during the drying process can increase respiratory losses, leach WSC, and eliminate increases in WSC created by pre-harvest management. The ensiling process makes retaining WSC even more complex since it involves the fermentation and subsequent conservation of a perishable product. Adequate WSC must be present to make rapid fermentation possible so that a stable pH may be achieved and maintained. As the forage crop matures the yield, dry matter content, nutritive value, WSC, and buffering capacity all vary and this variation is compounded by possible diurnal variation. Diurnal variation in yield is relatively minor but variation in dry matter content is related to environmental conditions. The diurnal variation in nutritive value and WSC is fairly well known but variation in buffering capacity is not well documented. Additional research is needed to tailor management recommendations to minimize losses of WSC due to rainfall and respiration in both the humid east and the western US. With silage crops, additional research on the relationship of buffering capacity to WSC and nutritive value is needed. This information is needed so that management recommendations optimize the likelihood of successfully making a high quality silage that is stable after the silo is opened for feeding.