Evaluation of the persistence of the selection effect by intra-family variability in egg weight and economic justification for the consolidation of the line of meat-egg chickens

Abstract

Goal. To assess the stability of the selection effect by intra-family variability in the weight of eggs in the second round of their selection, and provide an economic justification for the consolidation process of the factory line of meat-egg chickens. Methods. The study was conducted in 2025 on the basis of the experimental farm “Preservation of the state gene pool of poultry” of the State Experimental Poultry Station of the Institute of Animal Husbandry of NAAS on meat-egg chickens of the factory line of the G2 breed Plimutrok white of Ukrainian breeding. The following methods were used: experimental (comparative analysis of productivity and stability of breeding groups of birds formed according to two alternative selection schemes), zootechnical (individual accounting of productive indicators, selection, formation of the origin of birds), selection-genetic (assessment of phenotypic consolidation of groups according to the method of relative narrowing of intragroup variability of egg weight), calculation (analysis of economic efficiency), statistical (biometric data processing, calculation of coefficients of variation, classification of families by the level of phenotypic stability). Results. It was found that the re-selection of F1 generation of chickens by intra-family variability in egg weight provided a further reduction in the variability of the target trait by 1.2%, an increase in the level of phenotypic consolidation of the selection group compared to the baseline state of the line from 8.9 to 17.7%, the share of stable families — up to 89.5%, which confirmed the cumulative nature of the selection effect. Consolidation was accompanied by the formation of homogeneous batches of hatching eggs (by 6.6%), a moderate improvement in reproductive indicators (hatchability of eggs — by 2.5%, hatching of young stock — by 1.4%), and an increase in phenotypic uniformity of repair young stock F2 by live weight by 12.3% without reducing its preservation and growth rates. The cost of hatching eggs decreased by 9%, and the standard repair work by 3.4%. Economic efficiency indicators improved in the option with an alternative selection scheme, in particular, the European profit ratio coefficient Income Over Feed Cost (IOFC) increased by 13–19%. Conclusions. Selection by intra-family variability of egg weight provided a stable cumulative effect in the second round of selection, and contributed to the consolidation of the factory line of meat-egg chickens. The obtained results confirmed the expediency of using this criterion as a component of practical breeding programs aimed at increasing the technological predictability and efficiency of breeding poultry farming.