Effect of Heredity on Interior Egg Quality and Shell Composition

DURING storage or as they age, eggs of the domestic fowl undergo changes with respect to certain of their interior measurements. In addition to the general loss of moisture and accompanying shrinkage in weight, these changes have been shown by Holst and Almquist (1931) to include gradual liquefaction of the firm white, with a corresponding decrease in its percentage and an increase in the size of the yolk. Sharp and Powell (1930) showed that a change in the yolk index (ratio of height to width) occurred during storage, the yolk becoming broader and flatter when placed on a plane surface. These structural differences between fresh and storage eggs also exist between individual eggs when fresh and the author has recently shown (Munro, 1936) that eggs which possess larger than average percentages of firm white when fresh not only retain their advantage on holding but tend to break down or liquefy . . .