F. H. Abdou, M. E. Soltan, A. A. Enab
2019 Menoufia Journal of Animal Poultry and Fish Production  
The present experiment has been carried out at the Poultry Experimental Farm of the Faculty of Agriculture, Minufiya University, Shebin El-Kom, Egypt, during the period from 2013 to 2017 on Norfa chickens. Total of 475 dams were used in the present experiment in the base population, first and second generations. Independent culling levels (ICL) method of selection has been applied on the selected flock (x+.5sd). The criterion of (ICL) method of selection was to select hens having at least
more » ... ving at least average EN90 d + 0.5 sd on condition that egg size and body weight should be around the average flock. Results obtained and conclusions can be summarized as follows: -The actual genetic gains for EN90d and EN42WK were high from the expected genetic changes throw the base population, first and second generations by applied the Independent culling levels. -The selected line was excellent this of control line for productive traits in Norfa laying hens. -Concerning to phenotypic and genetic parameters, the heritabilites estimates showed that ASM had low h2 estimates, both of BWSM and BWM showed moderate h2 estimates, EWSM showed moderate to high h2 estimates while EWM had moderate h2 estimates and the heritability estimates for EN90d and EN42wk were moderate to high. -Generally, Norfa layers proved to have the advantage of early sexual maturity. -Norfa layers, in general have moderate egg size and this is mainly due to light body weight. More experiments are needed to increase egg size.
doi:10.21608/mjapfp.2019.117338 fatcat:x25xrqqh3ne33fxxtencdfkkpq