Seasonal Change in Nutritive Value of Bluestem Pastures

Abstract

Esophageally fistulated steers were used to determine organic matter intake and digestibility of bluestem pastures during the summer grazing season. Following a 48hour total fecal collection period, esophageally fistulated steers were used to collect grazed samples of native pastures during June, July, August, September, and October. Esophageal samples were higher in ash and crude protein and lower in crude fiber, N-free extract, and acid detergent fiber than were hand-clipped samples. In vitro dry and organic matter digestibilities were higher in forage collected by cattle than in handclipped forage. Multiple regression equations were developed to predict in vitro digestibility. Only crude protein and aciddetergent fiber were highly correlated with digestibility. Average daily intakes of organic matter, digestible crude protein, and digestible energy by steers on pasture were estimated from fecal nitrogen regression established from hay trials. Protein apparently became limiting about mid-July and energy in late August. The positive effects of burning were increased forage yield and weight gain with lowered lignin content. A foremost problem in range and pasture nutrition is accurately assessing chemical and botanical compositions of diets of grazing livestock (Van Dyne and Torell, 1964).

Flowering phenology as a functional trait in a tallgrass prairie

“…Although we did not see a decline in foliar d 15 N (Fig. S3) that would suggest lower N availability later in the season , foliar N concentrations of lateflowering species were lower, consistent with the general decline in N concentrations over time seen for individual species (Rao et al, 1973) and the seasonal decline in soil N mineralization and soil respiration previously observed (Turner et al, 1997;Johnson & Matchett, 2001). With few linkages between flowering phenology and functional traits, more research is necessary to understand the linkages that are present and to search for other functional traits that might be associated with flowering phenology.…”

Forage Yield, Nonstructural Carbohydrate Levels, and Quality Trends of Caucasian Bluestem

“…Levels ofNDF late in the summer (10 September) were below those oflate primary growth (30 July). Although the values presented here exceed the 500 to 600 g kg-• of diet NDF that supposedly limits intake due to rumen distention (Griffin et al, 1980;Van Soest, 1965), they are similar to and sometimes lower than those commonly found late in the grazing season (700 -800 g kg-1 ) for native warmseason grasses (Rao et al, 1972;Forwood et al, 1985).…”

Ecosystem Analysis of the Tallgrass Prairie: Nitrogen Cycle

“…A number of previous investigations have been concerned with fertilizing species that are important on the tallgrass prairie, such as little bluestem, Schizachyrium scoparium (White 1961, Dickinson 1964, Nixon and McMillan 1964, Reardon and Huss 1965, van Amburg and Dodd 1970, Rao et al 1973, Senter 1975, Waller et al 1975. In other instances, fertilizers have been added to the prairie and responses have been measured in terms of yield (Gay and Dwyer 1965, McMurphy 1970, Owensby et al 1970, Hyde and Owensby 1973, Dodd and Lauenroth 1979, species com-positional changes (Huffine and Elder 1960, Owensby eta!.…”