Agricultural Extension Service, South Dakota State College
In attempts to make selection more effective, swine breeders have become increasingly conscious of the importance of a good swine breeding program and of the part that heredity plays in improving performance and carcass quality. Breeders no longer select breeding stock on the basis of sight alone. Modern selection programs emphasize performance records and carcass cut-out values. This is desirable because research has indicated that visual inspection alone cannot identify animals which are genetically superior. Good feeding and management can result in larger, faster growing litters. However, these improvements in nutrition and management do not become a part of a hog's inheritance and are not automatically transmitted to the next generation. Lasting improvement is brought about by selecting parent stock with the best inherent makeup. This type of improvement depends on the use of performance information obtained through systematic testing and record keeping.
Kortan, L.J., "On-The-Farm Swine Selection" (1963). SDSU Extension Circulars. 586.