This measurement has subsequently been found to correlate well with other measures including static stiffness ( r = 0♹0) and eggshell thickness ( r = 0♷8) (De Ketelaere et al., 2002). ( 1999) devised a simple acoustic resonance test, which can be used to calculate the mechanical or dynamic stiffness of intact eggs. While these measurements have generally responded to selection, it has been notoriously difficult to prove that they directly relate to the incidence of breakage in the field (Thompson et al., 1985 Grunder et al., 1991).Ĭoucke ( 1998) and Coucke et al.
For decades, breeding companies have used laboratory-based measurements such as shell breaking strength, non-destructive deformation and specific gravity in their selection programmes (Preisinger and Flock, 2000). Nevertheless genetics remains an important way to reduce eggshell breakage, as it is both permanent and cumulative. To some extent the environmental factors can be controlled, for example, through improvements in bird management and nutrition. A complementary strategy is to improve the strength and quality of the eggshell by breeding.īoth environmental and genetic factors affect the strength or quality of any eggshell, and hence its likelihood of cracking during normal egg handling processes.
#Genstat 18 crack cracked#
Obviously any egg will break if it is hit hard enough (Carter, 1970) and as a result considerable effort has been directed at ways of reducing the insults experienced by eggs during routine egg handling procedures (Hamilton et al., 1979), and more recently at ways of detecting cracked eggshells online in packing stations (De Ketelaere et al., 2004). It is therefore in the interests of both egg producers and consumers that an attempt is made to reduce the number of cracked and damaged eggs.
Cracked eggs don’t just affect the economy however they also provide a direct route for pathogenic organisms to contaminate the egg contents (Messens et al., 2005) and as a result constitute a risk in terms of food safety. Assuming an average breakage of 5%, then the losses sustained by the UK industry in 2005 could have amounted to as much as £16♷ million, based on an average packer to producer price of 45 pence/dozen. In 2005, for example, the total eggs passing through UK packing stations was estimated to be 24 741 000 cases (360 eggs per case). The economic losses on a worldwide basis are difficult to estimate but for the UK industry an estimate can be made using the statistical data published annually by DEFRA. This results in substantial economic loss to the egg industry (Hunton, 1995). As this measurement also has a high heritability, it could be incorporated into breeding programmes, where it would offer an excellent method to improve eggshell quality and reduce the incidence of cracked eggs.Ĭracked and damaged eggs can account for between 6 and 8% of total production (Hamilton et al., 1979) and can be particularly problematic in older flocks. This study confirms that the dynamic stiffness measurement can predict the probability of an egg cracking in the field and with high precision. Additional variables (visit, egg weight,% damping and position in the house (battery, side and tier ) were also fitted to the model but only egg weight, visit and tier effects significantly improved the model fit.ĥ.
#Genstat 18 crack crack#
A logistic regression of the probability of cracking vs K dyn revealed that as the K dyn measurement decreases below 15 000 N/m there is a rapid increase in the probability that an egg will crack during routine handling.Ĥ. At the end of packing the acoustic test was repeated on the marked eggs, and these were subsequently categorised as being either intact (0) or cracked (1).ģ. These eggs were subsequently passed through online collection, grading and packing machinery, along with a volume of unmarked eggs. Intact eggs were marked and replaced in the front of the cages. Egg weight,% damping and dynamic stiffness ( K dyn) were recorded using an acoustic crack detection device. A representative sample of eggs ( n = 1660) was collected from the front of the cages in a commercial battery unit. The aim of this investigation was to test the predictive power of the dynamic stiffness measurement to identify eggs which are most likely to crack under field conditions.Ģ.
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