What information does a producer need to formulate diets more precisely?

Formulating diets on the basis of amino acid requirements has been available to Pennsylvania swine producers for over a decade. As additional synthetic amino acids become available, they should be included in the feed formulation process to obtain further reductions in nitrogen excretion. We suggest that all pork producers use amino acid balanced diets as the primary basis for all feeding programs. In addition to using synthetic amino acids to reduce crude protein and nitrogen excretion, diets should be formulated for the specific genotype, sex, and size of pig. Genetically leaner, more heavily muscled pigs require higher concentrations of essential amino acids than fatter, lighter muscled pigs. Female pigs (gilts) require more nutrient dense diets than castrated male pigs (barrows). Also, concentrations of dietary nutrients should be decreased as pigs grow. This technique is called phase feeding. Swine producers should know the genotype of their pigs, consider split-sex feeding, feed by phases, then formulate diets accordingly to limit nutrient excretion. This concept can also be employed in lactating swine. Diet formulation based on total feed intake should be used as a means of reduce nitrogen excretion during lactation.