Robert L. Gillen

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In spite of overwhelming experimental evidence to the contrary, rotational grazing continues to be promoted and implemented as the only viable grazing strategy. The goals of this synthesis are to 1) reevaluate the complexity, underlying assumptions, and ecological processes of grazed ecosystems, 2) summarize plant and animal production responses to(More)
Comparisons of stocking rates across sites can be facilitated by calculating grazing pressure. We used peak standing crop and stocking rates from six studies in the North American Great Plains (Cheyenne, Wyoming; Cottonwood, South Dakota; Hays, Kansas; Nunn, Colorado; Streeter, North Dakota; and Woodward, Oklahoma) to calculate a grazing pressure index and(More)
We evaluated the visual obstruction method as a non-destructive means of estimating herbage standing crop in tallgrass prairie. Prediction models were developed for both plot-level and pasture-level estimates by regressing standing crop from clipped plots on visual obstruction measurements (VOM) from 48, 20sample trials. Trials were conducted year-round on(More)
Beef cattle fitted with esophageal (four steers/pasture) or ruminal and duodenal (six calves/pasture; beginning BW +/- SE = 267 +/- 6 kg) cannulas grazed midgrass prairie rangeland (excellent range condition; MIDGRASS) or plains bluestem (Bothriochloa ischaemum var. Plains) pasture (BLUESTEM) in mid-May, late-June, mid-August, and mid-October of 1990 and(More)
Eight beef steers fitted with esophageal (four steers/pasture) and 12 beef calves fitted ruminal and duodenal (six calves/pasture; beginning BW = 267 +/- 6 kg) cannulas grazed either midgrass prairie rangeland (excellent range condition; MIDGRASS) or plains bluestem (Bothriochloa ischaemum var. Plains) pasture (BLUESTEM) during mid-May, late June,(More)
interval and that total forage production was higher for plots harvested at 6-wk compared with 4-wk intervals. Eastern gamagrass [Tripsacum dactyloides (L.) L.] is a perennial, The effects of plant population density on horticulwarm-season bunchgrass native to the Americas. Although much is tural and field crops is well established (Wade et al., known about(More)
Forage management practices influence the quantity and quality of forage available to grazing cattle. The objectives of this experiment were to determine the effects of prescribed fire or herbicides on the density of forbs, the production and nutritive value of the herbage, and the performance of beef steers grazing Yellow bluestem [Bothriochloa ischaemum(More)
Plains bluestem ( Bothriochloa ischaemum L.) is one of the primary grass species used for pastureland in Oklahoma. Plains bluestem is popular due to its high forage and beef production potential. It is also used for soil conservation on highly erodible areas. Despite the current importance of this species, N fertilizer sources, rates, and timing have not(More)