Measuring Egg Shell Strength by Beta Backscatter Technique

Effects of Dietary p,p′-DDT and p,p′-DDE on Egg Production and Egg Shell Characteristics of Japanese Quail Receiving an Adequate Calcium Diet

“…Egg shell thickness was measured at three places at the waist of each egg using a micrometer, after removal of the egg membranes. The beta back-scatter method of James and Retzer (1967), for measuring egg shell strength, was also used. Calcium was determined by atomic absorption analysis of solutions obtained by wet-ashing egg shells in concentrated hydrochloric acid.…”

Shell thickness, DDE levels in eggs, and reproductive success in common terns (Sterna hirundo), in Alberta

“…Most, however, were apparently thick enough to withstand normal turning by the adults during incubation. It must be noted that this variation in shell thickness may be attributable to a number of factors such as genetic strain, rate of egg production, dietary calcium, age of the adult, and environmental temperatures (James and Retzer 1967), and other factors such as agitation and aberrant behavior before laying. These variables may exert a synergistic effect in conjunction with DDE in influencing the reproductive physiology of adult birds.…”

Method for improving egg‐shell strength by selection12

“…In the selection generation, two samples of eggs were collected from each sire family at about 40 weeks of age, and each egg was measured for the number of emitted beta particles returned from the equator area (James and Retzer, 1967) in a 5-s period. The shell thicknesses of these eggs were also measured.…”