Ultrasonic eggshell thickness measurement for selection of layers

Abstract

This study aimed to develop a methodology for using ultrasonic technology (USG) to record eggshell thickness for selection of layers. Genetic correlations between eggshell strength and its thickness have been reported to be around 0.8, making shell thickness a selection index candidate element. Applying ultrasonic devices to measure shell thickness leaves an egg intact for further handling. In this study, eggs from 2 purebred populations of Rhode Island White (RIW) and Rhode Island Red (RIR) hens were collected on a single day in the 33rd week of the farm laying calendar from 2,414 RIR and 4,525 RIW hens. Beginning from the large end of the egg, measurements were taken at 5 latitudes: 0º (USG0), 45º (USG45), 90º (USG90), 135º (USG135), and 180º (USG180). To estimate the repeatability of readings, measurements were repeated at each parallel on 3 meridians. Electronic micrometer measurement ( EMM: ) were taken with an electronic micrometer predominantly at the wider end of eggs from 2,397 RIR and 4,447 RIW hens. A multiple-trait statistical model fit the fixed effect of year-of-hatch × hatch-within-year, and random effects due to repeated measurements (except EMM) and an animal's additive genetic component. The shell was thinnest in the region where chicks break it upon hatching (USG0, USG45). Heritabilities of shell thickness in different regions of the shell ranged from 0.09 to 0.19 (EMM) in RIW and from 0.12 to 0.23 (EMM) in RIR and were highest for USG45 and USG0. Because the measurement repeatabilities were all above 0.90, our recommendation for balancing egg strength against hatching ease is to take a single measurement of USG45. Due to high positive genetic correlations between shell thickness in different regions of the shell its thickness in the pointed end region will be modified accordingly, in response to selection for USG45.

Eggshell characteristics and cuticle deposition in three laying hen genotypes housed in enriched cages and on litter

“…The relationship between eggshell strength and eggshell thickness is very important to overall shell measurements and might differ according to the thickness of the shell. Kibala et al (2015) observed a genetic correlation between eggshell strength and its thickness was around 0.8, making the shell thickness a selection index candidate element. Ketta and Tumova (2017) indicated that ΔE* ab = √[(ΔL*) doi: 10.17221/75/2017-CJAS the eggshell strength was significantly increased as the eggshells became thicker.…”

Eggshell structure, measurements, and quality-affecting factors in laying hens: a review

“…Moreover, Yan et al (2014) studied the relationship between the uniformity of eggshell thickness and eggshell quality of Lohmann Brown eggs and reported that the uniformity of eggshell thickness is positively correlated with eggshell thickness (0.297), breaking strength (0.430), static stiffness (0.409), and fracture toughness (0.171) which might be used as an important indicator for other shell measurements in poultry breeding. Kibala et al (2015) developed a new methodology using ultrasonic technology to record eggshell thickness at different egg latitudes. The authors observed a genetic correlation between eggshell strength and its thickness to be around 0.8, making shell thickness a selection index candidate element.…”

Relationship between eggshell thickness and other eggshell measurements in eggs from litter and cages

“…They also indicated that, eggs with thin but more uniform eggshell were stronger than those with thick but less uniform eggshell. Moreover, Kibala et al (2015) reported a higher genetic correlations (0.8) between eggshell strength and its thickness making shell thickness as a selection index candidate element. However, thicker eggshells do not guarantee stiffer or stronger eggs (Bain 2005).…”