Comparing performance, morphological, physical, and chemical properties of eggs produced by 1940 Leghorn or a commercial 2016 Leghorn fed representative diets from 1940 to 2016

Eggshell quality is one of the most significant factors affecting the egg industry as it economically influences the quantity of saleable eggs. Eggshell quality can be improved through optimization of genotype, housing system, and mineral nutrition. This study aimed to compare genotypes and evaluate the morphological, physical, and chemical properties of eggs (weight, breaking strength, Haugh units, and dry matter) by hens of two different strains fed a 1940 and 2016 representative diet. Egg production was measured daily and there were four periods with 10-wk intervals in which eggs were analyzed starting at 30 wk and ending at 60 wk of age measuring quality parameters. This study was set as a 2 × 2 factorial. The factors consisted of 2 leghorn genetic strains that were a 2016 commercial layer (W36) and a 1940 random-bred leghorn line, then 2 diets based on 2016 and 1940 dietary standards. The treatment groups: 1) 2016 hen on 1940 diet, 2) 2016 hen on 2016 diet, 3) 1940 hen on 1940 diet, and 4) 1940 hen on 2016 diet had 8 replicates with 10 hens per treatment housing 2 hens per cage. Body weights were higher in the 2016 hens when compared to the 1940 hens, however, the feed conversion ratio fluctuated in hens with the 2016 hens on the 1940 diet consuming the most feed throughout the majority of the trial. The 1940s hens came into production later than the 2016 hens; however, the rate of production was consistent with one another. Oviduct and ovary weights were heavier in the 2016 hens when compared to the 1940 hens. Egg quality, both interior and exterior was greater in the 2016 hens when compared to the 1940 hens. Parameters measured demonstrated significant differences (P ≤ 0.05) among treatment groups suggesting that genetics and nutrition both played a role in production rate and egg quality.