the current study investigated the effect of short-term selection for four week body weight (bw) on performance of divergent lines of japanese quail and their crosses. the mean of bw at hatching time, one, two, three and four week oldand bw at sexual maturity time, age at sexual maturity, number of eggs (from 50 to 100 days old), mean of egg weight, percentage of fertility and hatchability in e...

The present study was carried out during two successive generations beside base generation, to improve egg mass (EM) through selection in developed Baheij chicken strain and to study correlated response of some production traits. The results showed that: 1Egg mass means for based generation (G0), first generation (G1) and second generation (G2) were 1741.29, 1904.52 and 2157.38g for S line and ...

It has been hypothesized that a high reproductive output contributes to the unique gigantism in large dinosaur taxa. In order to infer more information on dinosaur reproduction, we established allometries between body mass and different reproductive traits (egg mass, clutch mass, annual clutch mass) for extant phylogenetic brackets (birds, crocodiles and tortoises) of extinct non-avian dinosaur...

A study was conducted to investigate the effects of different betaine (BET) (0.0, 0.5 or 1.0 g/kg) and folic acid (FA) (0.0, 4.0 or 8.0 mg/kg) levels on performance, egg FA concentration and egg production of laying quails using 288 forty-two day-old Japanese quail in a 3 × 3 factorial arrangement of treatment based on randomized complete design. The results showed that none of the performance ...

The first objective of this study on broiler breeders was to investigate the genetic basis of variability in hatchability over age using a longitudinal model. Weekly percentage hatch of fertile and hatch of set eggs were available for 23,250 dams mated to 3,106 sires of the same age between the 28th and 54th week of life. Hatch of set was very highly correlated with fertility and showed a simil...

The identification and utilization of potential candidate genes with significant effects on economically important traits have become increasingly important in poultry breeding programs. The prolactin (PRLR) receptor is a specific receptor for prolactin, which is an anterior pituitary peptide hormone involved in various physiological activities and is essential for reproductive success. In chic...

The purpose of this study was to develop a nondestructive prediction method for the yolk: albumen ratio by computer image analysis for candling inspection. Twenty-two to 49 eggs per line were randomly sampled from four chicken lines. After weighing the eggs, the eggs were illuminated by an overhead projector beam through a small hole in dark room. Video images were taken of the eggs from four d...

Male secondary sexual traits are targets of inter- and/or intrasexual selection, but can vary due to a correlation with life-history traits or as by-product of adaptation to distinct environments. Trade-offs contributing to this variation may comprise conspicuousness toward conspecifics versus inconspicuousness toward predators, or between allocating resources into coloration versus the immune ...

the aim of the study was to evaluate the effect of storage and temperature on egg physical quality in hyline chickens line. a total of 150 eggs from college of natural resources farm were sampled for the present experiment. about 70 eggs each were stored in home refrigerator (temperature, 7.46±0.23 ˚c; relative humidity, 24.80±0.05%) and room temperature (temperature, 22.98±1.12 ˚c; relative hu...

The trade-off between reproductive investment and migration should be an important factor shaping the evolution of life-history traits among populations following their radiation into habitats with different migratory costs and benefits. An experimentally induced difference in migratory rigor for families of chinook salmon (Oncorhynchus tshawytscha), of approximately 86 km and 413 m elevation, ...