Nondestructive Deformation Research Articles

Redistribution and fusion of protein-lipid assemblies within the egg yolk sphere under slight non-destructive deformation causing a change in thermal gel properties

Egg yolk production processed after separating egg white is a common method to shorten cycle, but its taste quality will change even the vitelline membrane is intact. This might be related to the slight non-destructive deformation causing redistribution and fusion of protein-lipid assemblies within the egg yolk spheres. We investigated the mechanism of the change in thermal gel properties under slight deformation. The results of microscopic structural morphology revealed that the whole boiled egg yolk (WEY) underwent a transition in protein-lipid assembly morphology within yolk spheres, which changed from local aggregation to disordered fusion in shaken boiled egg yolks (SEYs). The spectroscopic and physicochemical properties analysis demonstrated that the redistribution of protein-lipid assemblies gave rise to marked changes in water migration, texture properties, molecular interactions, and oral sensation simulation of egg yolk thermal gels. This is benefit to guide the regulation of the taste quality egg yolk products in industry.

Effects of Adding Pectin to Milk in Varying Amounts on the Rheological Properties of Milk

Pectin, which is used as an additive in the food, cosmetics, pharmaceutical, and health sectors due to its safety, non-toxicity, low production cost, and high availability, is used as a thickener, gelling agent, brightener, stabilizer, emulsifier, and fat and sugar replacer in low-calorie foods. It is also used in milk and dairy products as a stabilizer to prevent proteins from clumping. In this study, the rheological properties of pectin and milk mixtures with pectin/milk powder (w/w) ratios of 0.1, 0.25, 0.5, 0.75, 1 and 1.5 were examined. First, a flow curve test was applied in the range of 0,01-1000 s-1 to obtain the viscosity curves and yield stress values of the samples. Then, an amplitude sweep test was performed at a fixed frequency of 10 rad/s and in the strain range of 0.01-100% to determine the linear viscoelastic range (LVR) of the samples and the solid and liquid structure of the samples. To determine the time-dependent behavior of the samples in non-destructive deformation, frequency sweep tests were performed at constant strain (0.01%) in the LVR range obtained from the amplitude sweep test and in the range of 0.1-100 rad/s. Finally, three interval thixotropy tests (3ITT) were performed to observe the structural recovery of the samples. As a result of rheological tests, it was determined that pectin-free milk showed Newtonian properties, other samples showed shear thinning properties, and viscosity values increased as the pectin rate increased. While all samples are solid at low strains, the liquid feature becomes dominant at high strains. It has been observed that as the pectin ratio in milk increases, the strain values at the yield point, where the liquid feature becomes dominant, also increase. Except for the sample with the highest pectin content, it was observed that the dominance of the storage modulus over the loss modulus was greater at low frequencies than at high frequencies. As a result of 3ITT, it was determined that the percentage of recovery at the 600th second increased as the pectin rate increased.

Nondestructive deformation measurements and crack assessment of concrete structure using close-range photogrammetry

Reliable measurement of deformations and crack assessment of concrete structural elements under loading is essential for evaluating the performance and durability of these elements. Traditionally, structural elements are monitored under loading with strain gauges, deflectometer, and data acquisition systems. Limited studies have investigated the potential of close-range photogrammetry and three-dimensional (3D) modeling in analyzing deformations, internal stresses/strains, and crack propagation. This research proposes an innovative four-phase testing method to develop 3D models of the concrete beam with close-range photogrammetry and image processing techniques. The proposed method entails the capabilities of analyzing deformations, internal stresses/strains, and monitoring crack propagation. The main phases of the proposed method are as follows: 1) preparing the test setups, beam preparation, photogrammetry preparation, and surveying preparation; 2) testing the beam under loading while recording deformation data, collecting high-resolution images, and conducting ground-controlled surveying from nine points around the beam; 3) performing photogrammetric processing of the images to generate a textured 3D model of the beam; and 4) comparing the results from both the 3D model and the direct measurements. For triangulation accuracy, the overall RMSE of the generated model is 4.974 mm. While for product accuracy, the RMSE is 9.303 mm. Moreover, the RMSE for deformations is 0.115 mm, indicating acceptable accuracy of measurements through the model. In addition, a photogrammetric-based deformation model can be generated for the beam surface, and cracks area, length, and width are efficiently extracted and monitored.

Wigner–Ville distribution based diffraction phase microscopy for non-destructive testing

ABSTRACTThe paper proposes an approach for non-invasive measurement of displacement derivatives and defect identification using an optical interferometric technique based on diffraction phase microscopy. Our approach relies on the application of Wigner–Ville distribution method in diffraction phase microscopy for directly extracting the phase derivative information, which is subsequently utilized for non-destructive deformation metrology. In addition, the proposed method offers good computational efficiency and robustness against noise for fast defect inspection. The performance of the proposed method is validated by experimental results.

Static Multiple, Distributed Piezoelectric Actuator Structural Deformation and Bending Analysis Using COMSOL

A paper revealing the static analysis of PZT actuator non-destructive deformation and displacement is unveiled in simulation here. PZT is known for two effects, direct and inverse piezo effects. Here it is used as actuator to realize the inverse piezo electric effect. These piezoelectric actuators are placed as 10 slices over an aluminium cantilever beam and the voltages are applied to one end while observing the deformation. The top piezos and the bottom piezos are electrically induced one at a time and successively all combinations are tried. Thus it yields the best possible locations of the actuators on any cantilever beam as to produce the desired deflection. This apart, the stress and strain on the piezos are notable in order to avoid certain combinations of induced electricity that may damage the piezos or the cantilever beam as observable from von-Mises stresses. The electrical ground is placed on the aluminium surface for the piezos. The entire substance for analysis is derived with the help of the finite element tool in 3D within COMSOL and the best possible combination of the actuators for the deflection and straining are discussed.

Long‐term selection using a single trait criterion, non‐destructive deformation, in White Leghorns: Effect over time on genetic parameters for traits related to egg production

Although non-destructive deformation is relevant for assessing eggshell strength, few long-term selection experiments are documented which use non-destructive deformation as a selection criterion. This study used restricted maximum likelihood-based methods with a four-trait animal model to analyze the effect of non-destructive deformation on egg production, egg weight and sexual maturity in a two-way selection experiment involving 17 generations of White Leghorns. In the strong shell line, corresponding to the line selected for low non-destructive deformation values, the heritability estimates were 0.496 for non-destructive deformation, 0.253 for egg production, 0.660 for egg weight and 0.446 for sexual maturity. In the weak shell line, corresponding to the line selected for high non-destructive deformation values, the heritabilities were 0.372, 0.162, 0.703 and 0.404, respectively. An asymmetric response to selection was observed for non-destructive deformation, egg production and sexual maturity, whereas egg weight decreased for both lines. Using non-destructive deformation to select for stronger eggshell had a small negative effect on egg production and sexual maturity, suggesting the need for breeding programs to balance selection between eggshell traits and egg production traits. However, the analysis of the genetic correlation between non-destructive deformation and egg weight revealed that large eggs are not associated with poor eggshell quality.

Multiple-trait analysis of a long-term selection experiment for non-destructive deformation in White Leghorns: Evolution of genetic parameters for traits related to eggshell strength

BackgroundEconomic losses resulting from poor eggshell quality are critical issue for the poultry industry, challenging researchers to find practical solutions to improve the resistance of eggshells to external pressure. Although many studies have proposed non-destructive methods to improve shell strength, relatively few long-term experiments are documented which use non-destructive deformation as a selection criterion. Using REML under a five-trait animal model, this study evaluates a long-term selection experiment for non-destructive deformation that was conducted on two divergent lines of White Leghorns and provides insight into how the selection process affects other traits related to eggshell strength (breaking strength, shell thickness, shell percentage, and shell weight). The evolution of the genetic parameters over the course of the experiment was analyzed also. ResultsThe heritability estimates for non-destructive deformation were 0.388 (±0.032) for the strong line and 0.415 (±0.030) for the weak line. For eggshell breaking strength, heritability values were 0.347 (±0.028) for the strong line and 0.482 (±0.032) for the weak line. Strong genetic correlations were found between non-destructive deformation and eggshell breaking strength (−0.774±0.031 and −0.840±0.022 for the strong and weak lines, respectively). Estimated heritabilities for the other traits varied from 0.448 to 0.591 for the strong line and from 0.493 to 0.672 for the weak line. In addition, these traits showed large negative genetic correlations with non-destructive deformation, from −0.623 to −0.903 for the strong line and from −0.730 to −0.934 for the weak line. Moreover, the regression coefficients associated with the generation means of the breeding values revealed an asymmetric response between the two lines, and further analysis of the evolution of the genetic parameters over the course of the experiment hinted at possible reasons for this asymmetry. ConclusionsThe large genetic correlation between non-destructive deformation and eggshell breaking strength and the similarity of the heritability estimates for these two traits (medium to moderately high), suggest that non-destructive deformation can be used instead of breaking strength as a means to evaluate eggshell strength. Nevertheless, additional research is necessary to better understand the effect of selection for non-destructive deformation on factors not considered in this study, such as egg production and hatching rate.

Effect of Long-Term Selection for Non-Destructive Deformation on Egg Shape in White Leghorns.

Several conventional traits, including eggshell thickness, are commonly being improved genetically as a means to increase eggshell strength. At the same time, researchers have come to recognize that factors related to egg geometry, such as egg shape, are important determinants of the variability remaining in eggshell strength, after conventional traits have been considered. Therefore, given that the value of the egg shape index –the egg's width to length ratio–depends highly on the hen strain, it is necessary to examine the relationship between eggshell strength and shape index more closely in a variety of breeds. From this perspective, by using REML methodology under a five-trait animal model, we analyzed a two-way selection experiment for non-destructive eggshell deformation in 31 generations of White Leghorns, to evaluate the effect of selection for eggshell strength on egg shape. In the strong line, which refers to the line that was selected for decreased non-destructive deformation value, the genetic correlation between eggshell breaking strength and shape index was 0.285±0.055, whereas that between non-destructive deformation and shape index was −0.021±0.063. In the weak line, these values were 0.244±0.055 and −0.093±0.060, respectively. The heritability estimates were 0.381±0.033 for non-destructive deformation, 0.349±0.029 for eggshell breaking strength, and 0.544 ±0.027 for shape index in the strong line, and 0.408±0.031, 0.468±0.032, and 0.484±0.028, respectively, in the weak line. The genetic correlation between eggshell breaking strength and shape index suggests that rounder eggs are somewhat more resistant to breakage than more elongated eggs. The moderately high heritability estimates for shape index indicate the potential to improve egg shape through genetic gain.

SAP FLOW DYNAMICS AS A DIAGNOSTIC TOOL IN NORWAY SPRUCE

Top-dieback of Norway spruce (Picea abies) trees has been observed in SE Norway. Trees usually die within 1-4 years after the first symptoms become visible and the dieback cause is unknown. The aim of our study was to establish when the irreversible spiral to tree death occurs. We assumed that hydraulic dysfunction, exemplified here by the sap flow reduction, was the final trigger of tree decline. We used the non-destructive heat field deformation method (HFD) to monitor the sap flow density (SFD) in non-symptomatic trees. After felling the trees we used the modified differential translucence method (MDT) to evaluate the sapwood translucence as an additional indicator of its functionality. In this study we show three examples of non-symptomatic trees with widely different sap flow densities detected by the HFD; tree A with unchanged sap flow throughout the monitoring period, tree B with decreasing sap flow in the last formed annual rings and minimal sap flow detected in tree C, which also started to show the first visible signs of dieback. In contrast, the MDT method detected in all cases functional (translucent) sapwood. In conclusion, we show that the sap flow reduction may occur during a relatively short period, prior to occurrence of any visual symptoms. Also, dysfunctions in sap flow could not be detected by the MDT method, as the sapwood still looked translucent and thus functional, although minimal sap flow was detected in that area by HFD method. Here we demonstrate the sensitivity of the HFD method in detecting the quantity of sap flow and thus a suitable diagnostic tool to evaluate the vitality in Norway spruce trees before the onset of visible disease symptoms.

Subfrontal Schwannoma Mimicking Neuroblastoma: Case Report

Computed tomography (CT), performed in a healthy 28-year-old man after minor head injury, detected a frontal base tumor. Neurological examination revealed left hyposmia. On magnetic resonance imaging scans, there was a heterogeneously enhanced tumor located in the left paramedian frontal base with extension into the left ethmoid sinus. Angiography showed a hypervascular mass in the left anterior cranial fossa; it was mainly fed by the left ethmoidal artery. Positron emission tomography scanning showed moderate accumulation of 11-methylmethionine and low accumulation of 18-fluorodeoxyglucose (FDG) at the tumor site. Bone image CT disclosed compressive, nondestructive deformation of the left frontal base. The preoperative diagnosis was olfactory neuroblastoma or meningioma. The tumor was totally resected via bifrontal craniotomy. The tumor was histologically diagnosed as typical schwannoma; it was positive for S-100 protein. We report a rare subfrontal schwannoma with extension into the nasal cavity that mimicked neuroblastoma. Low FDG accumulation and compressive deformation of the anterior skull base may help in the differential diagnosis of these tumors.

Association between ovocalyxin‐32 gene haplotypes and eggshell quality traits in an F2 intercross between two chicken lines divergently selected for eggshell strength

Broken and cracked eggshells contribute significantly to economic losses in the egg production industry. We previously identified ovocalyxin-32 as a potential gene influencing eggshell traits, by analysing an intercross between two parent lines developed from the same founder population by a two-way selection for eggshell strength with non-destructive deformation (DEF) conducted over 14 generations. We determined the nucleotide sequences of six ovocalyxin-32 exons in the parent individuals and analysed the association between ovocalyxin-32 and eggshell traits in the F2 individuals. We identified three haplotypes (W, M and S) of ovocalyxin-32 in the parent individuals. A mismatch amplification mutation assay was performed to distinguish six diplotype individuals (WW, MM, SS, WM, MS and WS) inthe F2 population. The egg weight (EW) of SS-diplotype individuals was significantly higher than that of WW-, WM- and WS-diplotypes. Short length of the egg (SLE) of SS-diplotype individuals was significantly higher than that of WW-, WM- and MS-diplotypes. Long length of the egg (LLE) of SS-diplotype individuals was significantly higher than that of WM and WS-diplotypes. DEF of WW-diplotype individuals was significantly higher than that ofSS-, WM, MS and WM-diplotypes. Haplotypic effect analyses showed significant differences between the W-haplotype and the S-haplotypes in the EW, SLE, LLE and DEF. The DEF of M-haplotype was significantly lower than that of W- and S-haplotypes. These results suggest that S- and M-haplotypes are critical for high quality of eggshells in the F2 population. In conclusion, ovocalyxin-32 is a useful marker of eggshell traits and can be used to develop strategies for improving eggshell traits in commercial layer houses.

Mapping of Quantitative Trait Loci Affecting Eggshell Quality in an F 2 Population Derived from Strong and Weak Eggshell Lines of the White Leghorn Chicken Breed

Broken and cracked eggshells cause major economic losses to the egg production industry. An F 2 population of 262 hens obtained by crossing a strong egg shell line with a weak egg shell line of the White Leghorn breed was used for detecting the quantitative trait loci (QTL) affecting eggshell quality. The 2 lines were developed from the same founder population by two-way selection for egg shell strength with nondestructive deformation. Of the 1 014 microsatellite markers tested, 35 were mapped on 10 autosoma1 linkage groups. There was no informative marker on chromosome Z. The QTLs associated with 7 traits, i.e., body weight, short length of egg, long length of egg, eggshell strength, eggshell thickness (EST), eggshell weight (ESW), and egg weight (EW), were identified. Highly significant ( P < 0.01) QTLs associated with EST and ESW and a significant ( P < 0.05) QTL associated with EW were mapped to a region flanking ABR0545 and ABR0362 on chromosome 9. These QTLs are good candidates to be employed in the development of strategies for reducing the number of broken and cracked eggs in commercial layer houses by employing marker assisted selection.

Mapping of quantitative trait loci affecting eggshell quality on chromosome 9 in an F2 intercross between two chicken lines divergently selected for eggshell strength

Broken and cracked eggshells are major causes of significant economic losses to the egg production industry. The quantitative trait loci (QTL) on chromosome 9 influencing the quality of eggshells were identified by analysing an intercross between two parent lines developed from the same founder population by a two-way selection for eggshell strength with non-destructive deformation conducted over 14 generations. Chromosome-wide highly significant (P < 0.01) QTL associated with egg weight (EW), short length of egg (SLE), long length of egg (LLE) and eggshell weight were mapped to the distal region of chromosome 9. Among the QTL affecting EW, SLE and LLE, ovocalyxin-32 was identified as a potential candidate gene influencing eggshell traits. Marker-assisted selection based on these QTL could be used to develop strategies for reducing the breakage and cracking of eggs in commercial layer houses.

Prediction of blood orange MT firmness by multivariate modelling of low alterative penetrometric data set: A preliminary study

A study was conducted to evaluate a non-destructive method able to predict Magness–Taylor (MT) penetrometric firmness of blood oranges, potentially applicable for on-line selection. The method consisted of multivariate modelling of non-destructive penetrometric measurements performed on intact oranges with a 11.3 mm diameter probe by digital dynamometric equipment. The tests were carried out on 366 blood oranges ( Citrus sinensis (L.) Osbeck cv. Tarocco); 60 were used as a control group to verify the non-destructive nature of the tests. Four test factors were used on the fruit: two different levels of non-destructive deformation (1 and 3 mm), at two different deformation speeds (5 and 30 mm s −1). In order to obtain the reference parameter (MT firmness), a destructive penetrometric test followed each non-destructive deformation on the same fruit (deformation of 20 mm at 1 mm s −1). The force–deformation curves of the non-destructive tests were elaborated to calculate different texture parameters (max force, elasticity, work). These parameters with raw curve data (force values for constant deformation steps) were used, after autoscaling pre-processing, as X-block datasets in supervised multivariate modelling (partial least squares) to predict MT firmness values. Among the test factors used, the 30 mm s −1 speed and 3 mm deformation provided the best overall prediction of MT firmness. This comprised an r value of 0.76 and standard error of prevision (SEP) of 2.99 N for a MT firmness mean value of 35.65 N (8.4%). The time needed to apply the selected deformation may lead to a sorting speed of about 10 fruit per second, representing an acceptable value for commercial application.

Recent advances in the assessment of eggshell quality and their future application

Any approach which aims to improve the quality and safety of eggs, is of limited value unless it can relate to the incidence of breakages in the field, and can be applied either directly to breeding programmes or used as online tools for quality assurance. Online systems require the method of assessment to be non-destructive. This is probably not so important for breeding companies who tend to gauge the usefulness of an eggshell quality measurement by its ease of measurement, its heritability and, its genetic correlation with other phenotypic traits. Historically, qualitative measures such as shell breaking or puncture strength, non-destructive deformation and specific gravity have been widely adopted as tools in selection programmes. The dynamic stiffness is a novel eggshell quality measurement, which could be utilised by poultry breeders as it has a moderate heritability and high genetic and phenotypic correlation with other shell quality traits including eggshell breaking strength. This non-destructive measurement could also be applied on-line to monitor shell quality. An alternative approach is to use genetic markers as tools to aid conventional breeding programmes where an important eggshell quality trait is practically too difficult or expensive to fully exploit. Marker-assisted selection for the genes coding for organic matrix proteins may provide a way of incorporating other beneficial egg quality traits into selection programmes in the future.

Effect of environmental enrichment during the rearing phase on subsequent eggshell quality in broiler breeders

1. This study set out to investigate if access to an enriched environment during the rearing phase influences subsequent production and eggshell quality in broiler breeders. 2. Broiler breeder pullets were reared under standard rearing conditions (control treatment) or under standard conditions with an environmental enrichment of bales of plastic-wrapped wood shavings (enriched treatment). At 19 weeks of age both groups were transported to a laying facility and housed in standard pens according to treatment type. 3. Egg weight, shape, shell thickness, non-destructive deformation, breaking strength, stiffness and ultrastructural quality were compared at beginning of lay (25 weeks old), peak production (31 weeks old), mid-lay (45 weeks old) and end of lay (57 weeks old). Production and hatchery data were also collected throughout lay. 4. Significant treatment–age interactions were detected for non-destructive deformation, breaking strength and stiffness, such that birds which had received prior enrichment went on to maintain a better shell quality with age. The measurements of total shell thickness, mammillary thickness and effective shell thickness all showed a trend for a treatment–age interaction. 5. Significant age effects were found for weight, shape index, shell thickness, breaking strength and stiffness. All production and hatchery data also demonstrated significant changes with age. 6. It is concluded that early enrichment with bales of wood shavings may provide a novel approach to the maintenance of eggshell quality at a time when calcium metabolism begins to reduce in efficiency.

The influence of thermal precompression on the mechanical behaviour of Ag-sheathed (Bi,Pb)2223 tapes with different matrices

The behaviour of the critical current in longitudinally strained Bi,Pb(2223) tapes shows a strain-insensitive plateau up to an irreversible strain limit ε irr. For higher strains, the formation of cracks induces an abrupt decrease of the critical current. We investigate the relationship between precompression and irreversible strain limit with a set of tapes made with different filling factors as well as an in situ Inconel 600-reinforced tape. I c( ε) curves were measured in a longitudinal strain apparatus at 77 K. The precompression at the measurement temperature is numerically estimated for each sample as well as the evolution of precompression during the cool-down. These calculated values are compared to the fracture susceptibility of extracted filaments, which gives an empirical estimate of the precompression. The main hypothesis of the “Irreversible I c Reduction Model” is confirmed, i.e. the irreversible strain limit essentially depends on precompression. However, we also found that the regime where I c remains constant contains a tensile component: the plateau extends beyond the external tensile strain needed to relieve the thermal precompression and includes a regime where the ceramic is further elongated non-destructively. This non-destructive deformation can be understood as a “connected-grains” behaviour, and extends the strain-insensitive plateau ∼0.1% beyond the precompression strain. This value is confirmed with a three points bending experiment performed on single filaments which gives a similar value for the bending failure strain. A comparable regime was found to exist also under compressive strain. These non-destructive regimes are of great importance for practical applications since up to a certain level the precompression can develop without any I c degradation.

Nondestructive firmness sensing using a laser air-puff detector

Abstract Recent studies indicate that peaches harvested at the right maturity stage are preferred by consumers. Reliable means of assessing peach maturity will increase efficiency and reduce costs. Current methods for determining harvest maturity of peaches are either subjective or destructive and are inherently inconsistent and wasteful. Nondestructive and objective methods for maturity sensing are needed. A laser air-puff firmness detector (consisting of a sample holder, a surge air tank, a displacement laser sensor, and a solenoid valve) was used to nondestructively measure the firmness of an engineered rubber ball inflated to an internal pressure of 13.8–34.5 kPa, and then three cultivars (Dixie Red, Harvester, and Sun Prince) of peaches at different maturities. The readings were related to peach mass and the penetrometer firmness from the Instron universal testing machine. The rubber ball deformation increased linearly as the tank air pressure increased ( R 2 =0.94 and 0.97). The firmness of the rubber ball indicated by compression tests was highly correlated with the firmness indicated by the laser air-puff detector ( R 2 =0.985). Peach mass and nondestructive deformation both increased and destructive penetrometer firmness decreased with time towards the optimum picking date. These results show that the laser air-puff firmness detector was able to sense the firmness of peaches. Multiple regression analysis showed a significant correlation among laser air-puff, penetrometer firmness, and mass data of peaches ( R 2 =0.774).

Correlations Between Measures of Eggshell Quality or Percentage of Intact Eggs and Various Economic Traits

Correlations between various shell quality traits or percentage of eggs remaining intact and economic traits were studied in F1 and F2 populations of White Leghorns. Eggshell quality traits were measured early (42 or 45 wk of age) or late (67 or 68 wk of age) and included specific gravity, nondestructive deformation, compression fracture strength, shell weight, and shell weight per unit surface area. Percentage of eggs remaining intact from oviposition to placement in fiber trays after being washed, candled, and sorted was measured. Economic traits studied included egg production traits, egg traits, and hen traits.All phenotypic correlations between shell quality traits or percentage intact and economic traits were low, being equal to or less than .21. High egg production was associated with low shell quality. However, high egg production from 386 to 497 days was associated with early high percentage intact [(genetic correlation) rg = .38, P<.05] but was not correlated significantly with percentage intact at other ages. The egg traits, Haugh units and blood spots, were not associated with shell quality traits or percentage intact. As for hen traits, high BW at 365 days was associated with high shell weight (rg = .23 and .32, P<.05). Other correlations involving age at first egg, viability, fertility, and hatchability were antagonistic to selection objectives in some instances, but were not significant. It was concluded that the genetic correlations between egg specific gravity or other shell quality traits and economic traits would allow improvement in percentage intact without seriously compromising selection objectives for other traits.

Genetic Parameters of Egg Shell Quality Traits and Percentage of Eggs Remaining Intact Between Oviposition and Grading ,

This study was performed to estimate heritabilities and genetic as well as phenotypic correlations of the egg shell quality traits specific gravity (SG), nondestructive deformation (DFM), compression fracture strength (CFS), shell weight (SW), percentage shell (% shell), and shell weight per unit surface area (SW/SA) and percentage of eggs remaining intact (% intact) from oviposition to placement in fiber trays after grading. In the first year of the 2-yr study, eggs were obtained from about 1,000 F1 hens from each of two crosses of selected Single Comb White Leghorn strains (01 × 03 and 02 × 04) when they were 42 and 68 wk of age. At each age, the shell quality of eggs collected on Sunday for 3 consecutive wk was measured whereas eggs collected Monday through Thursday of each week passed through egg washing, candling, and grading equipment before being hand candled to determine % intact. Eggs from F2 daughters were measured in a similar manner the following year.Heritability estimates tended to be highest (.29 to .59) for SG, SW, % shell, and SW/SA, somewhat lower (.21 to .33) for CFS, and lowest (.10 to .26) for DFM and % intact. Absolute phenotypic correlations between egg shell quality traits and % intact ranged from .19 to .47 whereas genetic correlations ranged from .23 to 1.04. Estimated genetic correlations between % intact eggs late in the laying year and egg shell quality traits early in the laying year were .50 and .62 (SG), .47 and .59 (CFS), .45 and .49 (% shell), –.37 and –.46 (DFM), .42 and .43 (SW/SA), and .23 and .30 (SW). Taking into consideration heritability, genetic correlation, and ease of measurement, the best shell quality trait for use in selection programs for improving % intact is SG.