Potential Alfalfa-Grass Grazing Systems for the Southern Plains.

Alfalfa (Medicago sativa L) is high quality perennial forage legume that may have potential in grazing grass-legume systems, especially with newly released grazing tolerant varieties like Bulldog 505.  Tall fescue [Festuca arundinacea Schreb. = Lolium arundinaceum (Schreb.) S.J. Darbyshire] and rye (Secale cereale L.) are commonly grown cool-season pasture grasses for cattle production in Oklahoma.  Combining alfalfa with cool-season grasses may improve seasonal distribution and reduce N fertilizer inputs.  The objective of this study was to evaluate animal production of alfalfa-tall fescue (PDF 584) and alfalfa-rye (‘Maton II’)- pastures in south-central Oklahoma.  The pasture treatments were arranged in three replications of a completely randomized design. Due to first year establishment, the grazing periods were Mar 2010 through June 2010.  There were no differences in average daily gain (0.73 kg animal^-1 d^-1), total gain (293 kg ha^-1), or days on pasture (399 d ha^-1) between the two systems.  These gains were slightly lower than the five yr average of rye and tall fescue systems receiving 112 kg N ha^-1 (448 vs 385 grazing d ha^-1; 1.05 vs. 0.93 kg d^-1; 491 vs. 347 kg ha^-1, respectively).  This experiment will need to be conducted over several years along with an economic analysis before conclusions can be made regarding the use of alfalfa to replace N fertilizer in tall fescue and cereal rye systems, especially since the economics is very sensitive to length of stand.