NUTRIENT BALANCE IN THE DIET OF GRAZING DAIRY-COWS

A method is described for estimating the nutrient content of pasture s elected by grazing cows. The method is non-invasive and suitable for u se on commercial farms. Results from use of the method are reported fo r studies on a commercial farm over a period of 29 months. Confidence limits were calculated for estimated nutrient contents of pasture eate n. Estimated nutrient contents then were compared with recommended nut rient contents for high-yielding cows. Significant deficiencies of ene rgy, protein, Ca, P and Na were common. Seasonal trends in nutrient co ntent of pasture eaten are reported, together with selection different ials between pasture eaten and pasture available.