Default forage species are artefacts of management and climate and may not be those initially planted or designed for current use. Some producers believe that default species are superior to those bred specifically for a purpose because of traits associated with survival. Pastures consisting of default (80% quackgrass-smooth bromegrass: 20% Kentucky bluegrass) and improved species, perennial, meadow bromegrass-alfalfa, or annual, winter triticale – oat mixtures, were compared for beef production within sequential summer and stockpiled systems over five years at Lacombe, AB, Canada. All pastures received broadcast applications of 100 kg/ha fertilizer-N and annual pastures were sown each spring. Crossbred beef heifers (328 +/- 3 kg initial wt.) were rotationally grazed within replicated paddocks using the Put and Take method. Summer and Stockpiled meadow bromegrass-alfalfa pastures averaged over years had 6 and 56% alfalfa, respectively. Winter triticale composition of annual pastures ranged from 23 to 57% averaged over systems.  The Summer, annual pasture (grazed June, July and September) had 7 to 62 less pasture days than the perennial pastures, but carrying capacity, animal weight gain and beef production per ha were significantly less than meadow bromegrass-alfalfa in 2, 3 and 2 of 5 yr, respectively.  Summer, perennial pastures performed similarly.  Stockpiled meadow bromegrass – alfalfa and annual pastures (grazed September and October) had twice the stocking rate, carrying capacity and beef production compared to the default pasture.  Thus, improved Stockpiled pastures exhibited superiority over the default pasture due to late summer regrowth subsequently grazed in the Stockpiled system.