Egg Quality Characteristics of Three Genotypes of Layers As Affected by Holding Period in the Derived Savannah Zone of Nigeria

Freshness of an egg is a desirable factor for both domestic and industrial usage. The present study was carried out to investigate the effects of genotype and holding period on external and internal egg qualities. The three genotypes whose eggs were collected for laboratory analysis are Isa Brown (IB), Dominant black (DB) and Bovan Nera (BN). Freshly laid eggs were collected from the strains and divided into four different groups as follows: day 1, 10, 20 and 30. The 1st group was measured on first day, 2nd group on 10th day, 3rd group on 20th day while, the 4th group was on 30th day after oviposition. External egg quality traits measured included egg weight, length and width, while the internal qualities are albumen and yolk indices. Haugh unit was calculated by mathematical formular. Analyzed results showed that the three genotypes differed significantly in egg weight, egg length and shell thickness. IB genotype was superior to other genotypes in egg weight. There was no significant differences among the genotypes in other traits including Haugh unit. In addition, almost all the measured traits were significantly affected by holding period. Egg weight, albumen height and yolk height declined in mean values as the storage time increased. Haugh Unit which is a determinant of egg quality also declined sharply from day 1 to 30. It is therefore, suggested that eggs stored under room temperature is not fit for consumption after 10th day.