Genetic correlations between purebred and crossbred performance and purebred and crossbred heritabilities were estimated for egg production traits of laying chickens using a multivariate sire model accounting for additive relationships between sires. Two sire lines, denoted lines 1 and 2, were crossed to one dam line to produce crossbred progeny. Records for egg weight, egg specific gravity, an...

Growth hormone (GH) has diverse functions in animals, together with other hormones from the somatotropic axis. Here, chicken GH (cGH) was investigated in recessive white chickens and Qingyuan partridge chickens as a candidate gene affecting egg production traits. Chicken egg production traits were studied in association with 4 selected single nucleotide polymorphisms (T185G, G662A, T3094C, and ...

a total of 2000 records of egg quality of 746 birds and body weight data from 17th generation of fars native fowl breeding station were used to estimate the genetic parameters of egg quality and body weight traits. six univariate animal models with different random effects were fitted for each trait. a model with direct additive genetic and maternal permanent environmental effects was the most ...

Two breeds of chickens were used to develop reference family and detect QTLs affecting egg quality traits: cocks of a native Polish breed Green-Legged Partidgenous (GlP) and hens of Rhode Island Red (RIR). During the first 100 days of the laying period, the GlP hens lay about 40 eggs weighting on average 50 g, whilst the RIR flock laid 83 eggs with a mean weight of 60 g. QTL analysis of egg qua...

the present study was conducted to estimate correlations among performance and egg quality traits in iranian native fowl. data were collected from 21,679 birdsat the isfahan native fowl breeding center to derive genetic parameters for performance traits and egg quality traits were measured on eggs of 1,020 birds. genetic correlations of performance and egg quality traits were estimated with a b...

Heritability, environmentaland genetic correlations between body weight at hatch (BW0), eight (BW8) and twelve (BW12) weeksof age, body weight at sexual maturity (BWM), age at sexual maturity (AFE),the weight of the first egg laid by the hen (EWM), the mean egg weight from 28 to 32 wks (EW28-32) and egg numbers (ENs) were estimated by the restricted maximum likelihood method under an animal mod...

heritability, environmentaland genetic correlations between body weight at hatch (bw0), eight (bw8) and twelve (bw12) weeksof age, body weight at sexual maturity (bwm), age at sexual maturity (afe),the weight of the first egg laid by the hen (ewm), the mean egg weight from 28 to 32 wks (ew28-32) and egg numbers (ens) were estimated by the restricted maximum likelihood method under an animal mod...

OBJECTIVE Unravelling the determinants of parasite life-history traits in natural settings is complex. Here, we deciphered the relationships between biotic, abiotic factors and the variation in 4 life-history traits (body size, egg presence, egg number and egg size) in the fish ectoparasite Tracheliastes polycolpus. We then determined the factors affecting the strength of the trade-off between ...

The present research was designed to examine the genetic analysis of egg weight, egg yolk weight and egg albumen weight of Bovan Neva Black laying hens at 25, 51 and 72 weeks. For this purpose, thirty birds were selected from the layer flock in the Babcock University Teaching and Research Farm. They were individually housed in separate labeled battery cage. A total of thirty eggs were collected...

This study was carried out to investigate the effect of two housing systems on external and internal egg characteristics of a commercial laying bird. Two hundred and eighty pullet of Nera layers were divided into two even group kept in different housing systems (deep litter vs cage). External and internal egg quality traits were examined at 26, 30, 34 and 38wk. Data were then collected on egg w...