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Seven groups from a total of 147 Lohmann Brown laying hens were housed individually in cages from 21 to 80 weeks of age. Birds were divided into a control group and groups receiving layer mash formulated to commercial standards supplemented with either a single or double dose of supplemental calcium pidolate, with or without supplemental Hy-D at either a single or double dose. Egg quality was measured as shell quality, internal quality, shell colour and cuticle coverage. There was a significant main effect of hen age and treatment group on albumen height, Haugh unit, and yolk colour score. There was a significant main effect of hen age and treatment group on egg weight, eggshell weight, percentage shell, shell breaking strength, shell deformation, shell thickness, shell reflectivity before staining, a* after staining, difference in a* before and after staining, and cuticle single score value. There was a significant main effect only of hen age on translucency score. A significant interaction between hen age and treatment group was found for yolk colour score, shell weight, shell reflectivity, a* after staining, difference in a* before and after staining, and cuticle single score value. The results indicated that, with increasing hen age, there was a decrease in albumen height, Haugh unit, percentage shell, shell breaking strength, shell deformation and shell thickness. Yolk colour score and translucency score increased with increasing hen age The effect of treatment group on the measured variables was inconsistent although the addition of Hy-D appeared to have greater effects than the addition of calcium pidolate. |
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