초록
Genetic advances, changes in housing systems and new management strategies have made it necessary to thoroughly review conventional nutritional programs. The approach has changed from one of feeding to permit gradual depletion of fat and protein tissues to one of feeding to maintain long-term nutritional balance. Increasingly the sow is viewed as a dynamic system that can be described by a mathematical model. There is opportunity to improve the initial models through research to provide a better understanding of metabolism and key physiological events in the sow's reproductive life. Direct experimentation remains a very important tool for defining nutritional requirements. Recent data supports increases in amino acid recommendations during lactation. Voluntary feed intake remains an intractable problem during lactation.