Dynamic stiffness (Kdyn) as a predictor of eggshell damage and its potential for genetic selection

Genetic progress in reducing eggshell damage depends on having a measurement that can both predict if an egg will crack during routine handling and whose variance contains a substantial genetic component. We have demonstrated that the measurement of dynamic stiffness, derived from the acoustic resonance of the egg and its mass, fulfils both of these criteria. The heritability of dynamic stiffness is high (0.53) which indicates that a large component of its variance is genetically determined. Furthermore, it has been possible to demonstrate that dynamic stiffness of the egg can predict the probability that it will crack during its journey through a packing plant. The lower the value of dynamic stiffness, the greater the probability that the egg will crack in the packing plant. We believe this is the first demonstration of the relationship between a measurement of quality and actual damage. The measurement of dynamic stiffness, therefore offers an excellent method to improve eggshell quality and reduce the incidence of cracked eggs by its incorporation in to breeding programmes.