Dry Matter Digestibility of Fourwing Saltbush (Atriplex canescens) Mixed with Blue Grama (Bouteloua gracilis)

Abstract

Fourwing saltbush [Atriplex eaneseens (Pursh) Nutt.] is a widespread shrub in arid regions of tbe western United States, is highly palatable, and possesses high dry matter digestibility (DMD). This study compared the DMD of fourwing saltbush at four phenological stages of development when mixed in different proportions (100, 75, 50, 25 and 0%) with blue grama [Bouteloua gracilis (H.B.K.) Lag. ex Steud.]. Fourwing saltbush had higher DMD when alone than when mixed in any proportion with blue grama (P < 0.05). Dry matter digestibility was also higher in fourwing saltbush at earlier stages of phenological development (P < 0.05). Adding fourwing saltbush in any proportion to blue grama enhanced DMD. Further, it had positive or negative associative effects on DMD depending on mixture proportion and stage of development. These associative effects may be attributed largely to crude protein levels of the forage mixture.