Amounts and Distribution of Minerals in Washington Forages

Abstract

Samples of alfalfa hay and grass silage from Washington state were analyzed for crude protein, neutral and acid detergent fiber, ash, and mineral content. Subsequently, neutral and acid detergent fiber factions were analyzed for mineral elements. Calcium, magnesium, and copper in alfalfa were negatively correlated with percent neutral and acid detergent fiber and positively correlated with percent crude protein. For grass silage, phosphorus, potassium, magnesium, and zinc were positively correlated with percent crude protein. Percent of total mineral in alfalfa associated with neutral detergent fiber was calcium 24%, phosphorus 31%, potassium 1%, magnesium 5%, copper 29%, zinc 31%, and iron 77%. Percent of total minerals located in the acid detergent fiber was calcium 3%, phosphorus not detectable, potassium 3%, magnesium 2%, copper 43%, zinc 23%, and iron 19%. Percents were similar for grass silage. Additionally, copper and calcium in the neutral detergent fraction and calcium in the acid detergent fraction decreased with higher neutral and acid detergent fiber. A significant portion of calcium, phosphorus, iron, zinc, and copper are associated with the fibrous portion of alfalfa hay and grass silage.