Growth and Nutritive Value of Perennial C^sub 3^ Grasses in the Southern Great Plains

Spring and fall gaps in forage production systems utilizing winter wheat (Triticum aestivum L.) forage in the southern Great Plains have led to an interest in additional resources such as C^sub 3^ perennial grasses. We evaluated the potential of nine cool-season perennial grass entries to fill the gap in forage production and nutritive value through the fall and spring seasons over 3 yr in Oklahoma. Yield of dry matter and crude protein (CP), neutral detergent fiber, acid detergent fiber, and in vitro organic matter digestibility (IVOMD) concentrations were regressed on days to determine daily changes. Following excellent growth in the spring of the establishment year, yields in the fall were less and declined markedly in 1997. Spring growth achieved the minimum amount of forage (1100 kg ha^sup -1^) for good animal productivity, with most exceeding 2500 kg ha^sup -1^ by 1 February in the first 2 yr. In general, nutritive value (CP and IVOMD) declined with maturity, but most entries were adequate through March each year, but seldom exceeded minimum requirements for 1 kg steer gain d^sup -1^. When herbage was sequentially removed (staged), subsequent regrowth was not different due to month of staging through March of each year, after which yield was significantly reduced. When fall moisture was adequate for wheat pasture, wheat yield and nutritive value were higher than any perennial grass, but when moisture was limited, yields of wheatgrasses (Thinopyrum spp.) generally exceeded those of wheat. [PUBLICATION ABSTRACT]