Real-time combination of observed growth and feed intake performance with performance simulated by InraPorc® to apply precision feeding to growing pigs Precision feeding (PF) of growing pigs requires methods for real-time analysis of performance and prediction of nutritional requirements. Two calculation methods for reducing nutrient intake were evaluated. Individual daily kinetics of body weight (BW) and feed intake (FI) of 285 pigs, reared from 81 to 156 days of age (ad libitum feeding) were used. The PF1 approach (from the Feeda-Gene project) used the Holt-Winters and MARS methods to predict individual daily FI and BW, respectively. The standardised digestible lysine (dLys) requirement was calculated daily from the predicted performance using the factorial method. The PF2 method used 2200 virtual pigs whose performance was simulated using InraPorc®. By comparing FI and BW dynamics of real and virtual pigs, the 10 closest virtual pigs were selected daily for each real pig. Individual daily performance and expected dLys requirements were obtained by averaging the InraPorc® data of these 10 virtual pigs. PF was then simulated for each real pig. For each method, the blend proportions of two diets (A and B, 9.7 MJ net energy (NE)/kg, crude protein: 16.9% and 9.3%, dLys: 1.0 and 0.4 g/MJ NE, respectively) were calculated daily to achieve calculated requirements. Nitrogen (N) and dLys intake and N excretion were calculated individually. A two-phase (2-P) feeding strategy was also simulated (A:B = 83:17 until 65 kg PV, 50:50 afterwards). Compared to 2-P, N and dLys intake and N excretion were reduced by, respectively, 6.7%, 9.7% and 11.9% with PF1 and by 9.2%, 13.3% and 16.3% with PF2. The PF2 method provided better day-today stability of performance predictions, leading to a more regular decrease in N and dLys intakes during growth. The potential of this new method needs to be confirmed under field conditions.