A breeding goal for South African Holstein Friesians in terms of economic weights in percentage units

In South Africa the exact breeding goal for Holstein Friesians still needs to be determined. This means that the traits, which should be most importan t in selection have to be identified. One method to identify these traits c ould be to calculate economic weights for production and functional traits. Economic weights calculated in absolute units cannot be compared because s ome traits are measured in different units. The objective of this study was therefore the calculation of economic weights for production and functiona l traits, in percentage units, to make a comparison between traits possible . The production traits were milk, butterfat, protein and lactose yield and the functional traits included survival rate, feed efficiency, live weight and calving interval. The study used a simulation model to calculate econo mic weights. This model included three production enterprises classified ac cording to the production level of the herds. The results show that for all three the production enterprises milk yield is potentially the most import ant trait to improve in selection, with the second trait being feed efficie ncy followed by live weight. The results were confirmed by constructing a s election index, including milk yield and live weight, showing that economic improvement with a selection index is about 25% more efficient than direct selection for milk yield alone.