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Abstract
Improvements to the nutritional and harvest management of Southern pasture systems may benefit beef cattle producers in the Southeastern US. Potentially, this can be achieved by interseeding alfalfa (Medicago sativa) into bermudagrass (Cynodon spp.) which can improve the nutritive value of the forage base, improve overall animal performance, and extend the grazing season. The objectives of this research were to: 1) evaluate the concurrent production of alfalfa-bermudagrass (BGA) mixtures with bermudagrass monoculture pastures supplemented with (BGN) or without (BG) synthetic nitrogen, and determine the economic input these systems have on forage and animal productivity when grazed by stocker cattle, 2) to compare ‘Bulldog 805’ alfalfa interseeded into ‘Russell’ or ‘Tifton 85’ bermudagrass bases and the effect on forage and animal productivity when managed under three varied harvest management strategies of Cut only (CT), graze only (GR), or Cut and Graze (CG), and to determine the optimal harvest management strategy for alfalfa-bermudagrass mixtures in the Southeastern US; and 3) compare the predictive accuracy of three nondestructive sampling procedures in predicting herbage mass in alfalfa-bermudagrass mixed pastures when harvested to two stubble heights. BGA treatments resulted in a higher nutritive value for crude protein and total digestible nutrients, while also observing a greater average daily gain (ADG) and liveweight gain ha (LWG) for grazing stocker cattle compared to BG and BGN treatments. When alfalfa was interseeding into either Russell or Tifton 85 bermudagrass, it was observed that bermudagrass did not impact animal or forage responses. However, the harvest method strategy did influence the measured animal and forage responses, in that the CG treatment optimized the utilization of alfalfa-bermudagrass mixtures. Additionally, of the three nondestructive estimation techniques evaluated, rising plate meter, pasture ruler, or digital imaging analysis, none were able to reliably predict herbage mass in alfalfa-bermudagrass mixtures. As a result of these evaluations, the strategic management of alfalfa-bermudagrass mixtures is an essential practice for producers utilizing this mixture in their pasture systems.