The grower-finisher period has been considered to be the least complicated segment of swine production, but with newer genotypes and feeding strategies, it is becoming somewhat more complex. Approximately 75 to 80% of the total feed used per 100 lb. of pork marketed is consumed during this period, representing approximately 50 to 60% of the total cost of pork production. Several factors can, however, affect the grower-finisher pig's nutrient requirements. Those factors of greatest influence on the pig's growth rate and nutrient requirements are genetics, sex, herd health, environmental temperature, and stage of development. Nutrient recommendations for grower-finisher pigs of differing genotypes and for gilts and barrows within each genotype are presented in Tables 4 and 5.