Published online by Cambridge University Press: 20 November 2017
Significant increases in genetic merit for milk production in the UK dairy herd have led to high and persistent milk yields becoming relatively common. Data relating this level of performance to the extent of the energy deficit in early lactation, possible impact on milk quality and the contribution of mobilised energy to milk production are relatively scarce. The aim of this study was to compare lactational performance in high- (HYC) and average- (AYC) yielding cows and to reconcile changes in body status (liveweight and condition score) of HYC with associated measurements of energy depletion and repletion.