Modélisation de l’effet de la stratégie alimentaire et du contexte de prix de matières premières sur les performances moyennes, leur variabilité et les rejets azotés à l’échelle d’une population de porcs

Overview & Synopsis

A virtual population of 2000 pigs was used to simulate the effect of feeding strategy on the average performance and variability of the population, and on N output depending on the context of feed priees. The evolution of the average digestible lysine requirement of females was used to design a biphase strategy, combined with feed restriction or ad libitum feeding. Multiphase strategies were also tested in ad libitum conditions, with lysine levels ranging from -10% to +35% around the average requirement of females (FlOO}. Performance was simulated individually using lnraPorc® up to an average (population) final body weight of 115 kg. Nitrogen excretion and economie results were calculated in five different contexts of feed priees (2005/06 to 2009/10}, with or without limitations on the dietary crude protein content. Results indicated that the lysine supply should be 30% above F100 to maximize growth. However, when multiphase strategies above F100 are used, N excretion is increased. The best economie AA supply depends on the context of feed priees and limitation on the dietary formulation. A precision feeding technique, with tailored feed supply to individual pigs, allows for an improved margin per pig and a reduced N output. With a biphase strategy, simulations indicate that feed restriction allows for a reduction in variation in final body weight, increased margin and reduced N excretion.