Forage Evaluation and Quality in Florida

Warm-season grasses, also called C4, are the predominant forages for ruminant production in Florida. The C4 grasses grow well under high temperatures and generally cultivated between 25 N and 25 S of the equator. The C4 grasses are more efficient in fixing carbon dioxide than other grasses; however, they have a specialized thick-walled parenchyma bundle sheath around each vascular bundle, and much smaller proportion of more compact thin-walled mesophyll tissue than C3 grasses (Wilson, 1993). These anatomical characteristics results in plants with less concentration of crude protein (CP) and soluble carbohydrates, and greater concentrations of cell wall components such as cellulose and hemicelluloses than C3 grasses. The importance of the nutritional value of forages can have different implications depending on the production systems. For confined animals with greater concentrate supplementation, forage has been used as a source of fiber to maintain rumen activity, while for grazing animals forages may represent the only source of nutrients in the diet. The validity of a particular nutritive value entity is highly dependable on the forage use. Several methods to estimate nutritive value and quality of warm-season grasses have been published in the literature and the objectives of this paper are to: 1) describe the C4 forage species and cultivars used in Florida, and 2) discuss the methods used to estimate nutritive value of C4 plants.