INFLUENCE OF SEVERAL FACTORS ON EGG SHELL STRENGTH AND ITS PREDICTION

Abstract

Experiments were conducted to determine the effect of genotype, (reciprocal crosses), age of pullet (three consecutive 42-day periods) and egg storage treatment on the relationship of crushing strength to shell elasticity (the ability to recover from deformation and expressed as deformation per unit load), and to study the influence of storage treatment on crushing strength.Small but occasionally significant differences were noted among crosses and ages in the relationship of crushing strength to elasticity. Storage treatment exerted a much more marked effect on this relationship. The average increase in standard error of estimate incurred by pooling the raw data from all storage treatments was 15.0%, as compared with a maximum increase of 2.1% when the raw data for crosses or ages were pooled.Eggs stored in water, either intact or with the albumen and yolk removed, became progressively weaker throughout the 60-day storage period, as judged by a significant linear increase in elasticity. The strength of eggs stored at 21 °C in a normal or CO2 atmosphere and of those stored at 4 °C, with or without spray-oiling, underwent no significant change during storage.