Dry Matter Intake and Digestion of Perennial and Annual Cool-Season Grasses by Sheep1

Excess perennial cool-season grass production can be harvested as hay for feeding later. Thus, a series of experiments were conducted to estimate DMI and digestibility of perennial cool-season grasses relative to an annual cool-season grass hay. In Exp. 1, wheat (Triticum aestivum var. Pioneer 2174), tall wheatgrass (Thinopyrum ponticum var. Jose), smooth brome (Bromus inermis var. Lincoln), and intermediate wheatgrass (Thinopyrum intermedium var. Manska) were harvested in the spring as high-moisture hay and fed to lambs. At feeding, all 4 hays contained more (P < 0.05) ADF and less N than as standing forage. Apparent digestibility of the DM, NDF, and ADF fractions and DMI were not different (P > 0.10) among the hays used in this experiment. In Exp. 2, grasses were harvested as field-dried (DM >65%) hay from established stands of Jesup Max Q (Festuca arundinacea) and Nanyro (F. arundinacea) tall fescues, Harusakae meadow fescue (Festuca pratensis), and wheat (var. Pioneer 2174). Lambs fed wheat hay had greater (P < 0.05) DMI (69.3 g/kg BW0.75, respectively) compared with lambs fed Jessup or Nanyro (35.0 and 33.8 g/BW0.75), and lambs fed Harusakae hay had intermediate DMI (50.2 g/BW0.75). Digestibility of Jesup hay was greater (P < 0.05) than digestibility of the other 3 hays. Excess cool-season grasses can be harvested as high-moisture or field-dried hay, but harvested hays had greater concentrations of ADF and NDF and a lesser concentration of N than preharvest standing forage.