Prenatal and Postnatal Influences on Growth and Backfat in Swine

Abstract

AN understanding of the relationship between direct genetic effects and postnatal maternal effects is essential in formulation of optimum breeding programs for traits affected by maternal influences. In most mammals maternal effects are held to be an important component of performance. However, in swine, few studies have been reported concerning the relative importance of maternal effects or the relationships between maternal effects and other factors affecting performance. Cox and Willham (1962) reported important postnatal maternal influences on pig weight up to 98 days of age. Dickerson (1947) and Dickerson and Grimes (1947) have suggested a negative genetic correlation between “fattening ability” and postnatal maternal performance in swine. Several workers, e.g., Butler and Metrakos (1950) and Cox, Legates and Cockerham (1959), have reported important postnatal maternal influences on growth in mice. The study of maternal effects is complicated because a dam transmits a sample half of her genes to her young, and her genotype is also expressed in the prenatal and postnatal circumstances which influence the young. Copyright © 1971. American Society of Animal Science. Copyright 1971 by American Society of Animal Science.