A suspension weighing technique for the rapid determination of specific gravity of eggs

Abstract

A suspension weighing technique, developed for the rapid determination of the specific gravity of eggs, is described and compared with one using salt solutions of known density. A simple impact device was used to determine shell strength for correlation with the results of specific gravity determinations. Eggs were obtained from three strains of domestic fowl : White Leghorn, .Australorp, and Synthetic (a closed population in its eighth generation originally based on White Leghorn-Australorp crosses). The numbers of eggs examined in one hour by suspension weighing, salt solutions, and the impact device were 400, 200, and 100 respectively. Repeatabilities of specific gravity based on three eggs per hen were slightly higher for suspension weighing than for salt solutions. Correlations between specific gravity and breaking strength ranged from +0.72 to +0.78 for the three strains. Correlations between egg weight and specific gravity and between egg weight and breaking strength were effectively zero. It is concluded that for routine work, measurement of specific gravity by suspension weighing is a reliable and rapid method of estimating shell strength.