Nutrient balance in the diet of grazing dairy cows

Abstract

A method is described for estimating the nutrient content of pasture selected by grazing cows. The method is non-invasive and suitable for use on commercial farms. Results from use of the method are reported for studies on a commercial farm over a period of 29 months. Confidence limits were calculated for estimated nutrient contents of pasture eaten. Estimated nutrient contents then were compared with recommended nutrient contents for high-yielding cows. Significant deficiencies of energy, protein, Ca, P and Na were common. Seasonal trends in nutrient content of pasture eaten are reported, together with selection differentials between pasture eaten and pasture available.