In this study economic weights for production and functional traits of the
Holstein Friesians in South Africa were calculated using a simulation model
. The production traits were milk, butterfat, protein and lactose yield and
the functional traits included feed efficiency, survival rate, calving int
erval and live weight. The simulation model was developed for three product
ion systems and made use of two South African milk price systems to calcula
te the economic weights. In both price systems the feed efficiency had the
largest economic weight, followed by the four production traits. The econom
ic weights of the other functional traits were much smaller than the econom
ic weights of the production traits.