1. Genetic parameters of slaughter and carcase traits were estimated for 5-week-old Japanese quail reared under the one-to-one sire and dam pedigree recorded system. Data were analysed using restricted maximum likelihood (REML) with relationship matrix. Records of 1244 animals from 119 sires and 156 dams were analysed. 2. An individual animal model was used which had the animals’ genetic effect as the only random factor. Heritability and standard errors of slaughter, cold carcase, breast, leg, wing, others, liver weights and dressing percentage were 0·40 ± 0·07, 0·55 ± 0·07, 0·58 ± 0·07, 0·54 ± 0·07, 0·49 ± 0·07, 0·42 ± 0·06, 0·13 ± 0·04 and 0·21 ± 0·05 respectively. Moderate to high heritability for most of the studied traits suggested that selection to increase or decrease these traits will be successful. 3. The strongest genetic correlation was found between slaughter, carcase and breast weights (0·97–0·87). These high genetic correlations provide an opportunity to select for breast weight on the basis of 5-week weight. 4. It can be concluded that carcase weight and 5-week weight of quail can be included in a selection index to increase the weights of valuable carcass parts.

This study was conducted to determine the genetic parameters of internal and external quality traits of Japanese quail eggs. Two statistical models were used in the calculation of genetic parameters and variance components. While 286 eggs were used based on model 1, 1,524 eggs were used based on model 2. Genetic parameters of the first eggs were calculated with direct genetic effect included in the analysis as random factors by using model 1. Model 2 was used for all eggs (5 to 6 eggs from each hen for six rearing groups). As different from model 1, their permanent environmental effects were also included in the model 2. Heritability of egg weight, egg length, egg width, shape index, shell weight, shell thickness, and shell ratio among the external quality traits of the eggs was respectively found to be 0.44, 0.53, 0.51, 0.70, 0.19, 0.16, and 0.05, respectively, according to model 1. These values were found to be 0.46, 0.40, 0.74, 0.48, 0.60, 0.28, and 0.21, respectively, according to model 2. Yolk weight, yolk diameter, yolk height, yolk index, yolk ratio, albumen weight, albumen height, albumen ratio, and Haugh unit values among the internal quality traits of the egg were found to be 0.22, 0.32, 0.02, 0.16, 0.19, 0.34, 0.19, 0.17, and 0.17, respectively, according to model 1. These internal quality traits were found to be 0.27, 0.18, 0.38, 0.06, 0.20, 0.41, 0.15, 0.15, and 0.12, respectively, according to model 2. Consequently, in this study, strong genetic correlations were detected between albumen height and Haugh unit, and also between albumen height and albumen weight. Additionally, a high and positive correlation was observed between some yolk traits (yolk weight and diameter) and albumen traits (weight and height). All these genetic correlations can be used to improve egg quality with a selection according to albumen weight.

Introduction Geese are reared mainly for their meat, fat, feathers, and liver in different regions of the world. Geese are highly adaptable to different environmental conditions, resistant to climatic changes, and efficient in feed utilization because