The term ‘negative energy balance’ (NEB) is used to describe the condition in early lactation when the energy available from food intake is lower than that of the energy used by the cow for milk output, maintenance and activity. Current selection objectives may be favouring cows that are genetically predisposed to mobilise body tissue. This may have consequences for fertility since cows appear to resume reproductive activity only after the nadir of NEB has passed (Veerkamp et al., 2000). Extreme NEB may be considered generally undesirable, as it is a precursor to health and fertility problems. The aims of this study were: 1) to predict genetic merit for sires for traits contributing to energy balance; 2) to combine those breeding values into an overall energy balance evaluation for bulls using either daily energy flux or body state changes.