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Timothy (Phleum pratense L.) is the main forage grass species cultivated with alfalfa (Medicago sativa L.) in eastern Canada, yet its regrowth under dry and warm conditions is poor. Air temperature and water stress are predicted to increase in the near future, which could further reduce timothy's regrowth. We evaluated six alfalfa-grass binary mixtures at three contrasted sites in eastern Canada to find potential alternatives to the alfalfa-timothy mixture under current climatic conditions. Timothy, tall fescue (Schedonorus arundinaceus [Schreb.] Dumort.), meadow fescue (Schedonorus pratensis [Huds.] P. Beauv.), festulolium (x Festulolium Asch. & Graebn), perennial ryegrass (Lolium perenne L.), and meadow bromegrass (Bromus biebersteinii Roem. & Schult.) were evaluated with harvests either at the early bud or early flower stage of alfalfa. Dry matter yield, nutritive attributes, and the yield contribution of each species were determined. Alfalfa mixtures with festulolium (cv. Spring Green) and perennial ryegrass (cv. Remington) had inferior grass yield contributions due to winter damages, as well as inferior forage yield and estimated milk production per hectare; these cultivars are not currently viable alternatives to timothy in eastern Canada. In contrast, alfalfa-meadow fescue and alfalfa-meadow bromegrass mixtures produced comparable yields, nutritive value, and estimated milk production per hectare and they are, therefore, possible alternatives to the alfalfatimothy mixture. The alfalfa-tall fescue mixture also represents a possible alternative; its lower nutritive value was compensated by its slightly greater yield. Timothy, tall fescue, meadow fescue, and meadow bromegrass remained productive over the first three production years when cultivated in mixture with alfalfa.