Changes in the botanical composition and nutritive characteristics of pasture, and nutrient selection by dairy cows grazing rainfed pastures in western Victoria

Abstract

Changes in pasture metabolisable energy (ME), crude protein (CP), neutral detergent fibre (NDF), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sulfur (S), sodium (Na) and chlorine (Cl) were measured at each grazing, in 4 paddocks on 2 farms (farm A and farm B) in western Victoria from May 1995 to March 1997. Selection differentials were calculated from quality parameters using measures of pre- and post-grazing masses. Changes in botanical composition and pasture allowance were also measured. The nutritive characteristics of pasture on both farms followed similar trends. Metabolisable energy and CP were highest in winter and early spring with values of over 11 MJ/kg DM and 250 ..