Preservation of Nutrients in Cool- and Warm-Season Forages At Different Stages of Maturity and Management

The overall goals of the studies described in this thesis were to investigate management practices of tall fescue and native warm-season grasses (NWSG) and find the best time to harvest and method to preserve forage quality. Study one investigated the effects of maturity on tall fescue and switchgrass and the effects of preservation method on forage quality. This study confirmed that maturity reduced forage quality in both tall fescue and switchgrass. Both tall fescue and switchgrass were successfully preserved as haylage or hay and did not differ in forage quality. Forages harvested before mid-May met the TDN and CP requirements for winter feeding in both spring- and fall-calving herds. Feeding tall fescue from mid-May harvest to stocker cattle would result in a gain 0.45 kg/day based on TDN provided. However, switchgrass from the same harvests would result in stockers gaining 0.63 kg/day. Study two investigated the effects of multiple harvests, N fertilization, forage species, and preservation methods on NWSG quality and biomass production. Neither fertilization nor species had an effect on forage quality or biomass production. June harvested NWSG had similar forage quality regardless of preservation methods. Biomass production from switchgrass was reduced by a summer forage harvest, but a big bluestem/indiangrass mix stand was not. However, a June forage harvest paired with a biomass harvest resulted in greater yearly yields. Study three investigated the effects of treating and ensiling mature switchgrass with alkali on forage harvested in October and November. The October harvest had decreased NDF content when treated with alkali. Concentrations of at least three g of alkali treatment per 100 g of forage DM reduced NDF content, which could potentially improve forage intake. The results of these studies are promising and provide forage and livestock producers needed information on timing of harvest and preservation methods. However, more research needs to be completed to determine the ideal preservation method of cool- and warm-season grasses based on a cost benefit analysis in regards to the preservation of nutrients in forages and the ability to meet cattle requirements.