No abstract

Every year the leading breeding companies shorten broiler fattening time by days, i.e., the statistically average chick annually adds 50 60 g to its standard weight. During the past 10 years, the weight of its breast muscles has increased 3%. Broiler chicks reach a live weight of 1.8-2.0 kg in 35 days with a feed con version of 1.5-1.7 kg/kg, and egg production of meat chickens of the parent flock is 150-165 [1-3]. At the current breeding stage, great significance is attached to parent lines, on the productivity of which depend the indices of the parental forms and broilers. Research and production experience in breeding meat chickens indicates the need for constant improvement of methods and procedures for increasing the genetic potential of their breeding and productive qualities, allowing breeding of new populations and using them as material for creating new highly profitable, compet itive crosses in regions with various climate and eco nomic conditions [4,5]. Meat chicken lines and crosses adapted over the course of many generations yield the best results with respect to productivity and survival than those newly imported [4,6]. In connec tion with this, it is more expedient to use the genetic potential of foreign crosses for improving domestic meat chicken crosses under breeding center condi tions.The purpose of the present work was to use new procedures for evaluation and selection when creating parent lines of Plymouth Rock meat chickens (B7 and B9) of the Smena 8 cross. METHODThe investigations were carried out at the Smena Poultry Breeding Center on the basis of Plymouth Rock parent lines (B7 and B8), maternal parent form (B79), and broilers of the Smena 8 cross (B5679). The basic method of breeding the line poultry was com bined breeding on the basis of selecting the best stock, families, and individuals with high individual indices during intraline breeding as well as "introductory crossing" of a bird of the Ross 308 cross.Line B7, the parent line of the maternal parent form of Plymouth Rock, was created on the basis of genetic material of crosses Smena 7 and Ross 308 by single introductory crossing according to the scheme: (male symbol) R7 (Ross 308) and (female sym bol) G7 (Smena 7) with subsequent selection of the desired type, inbreeding, and directed in depth breed ing program for feed conversion, growth rate, meat forms, and feathering rate. Hens and roosters of line B7 are carriers of the dominant slow feathering gene. Day old cockerels and pullets are slow feathering with genotype Kk and KH. The type of feathering was established by visual examination of the wing feathers. In day old chicks with slow feathering, the coverts are longer or equal to the remiges.Line B9, the maternal line of the maternal form of Plymouth Rock, was created on the basis of genetic material of crosses Smena 7 and Ross 308 by single introductory crossing according to the scheme: (male symbol) R7 (Ross 308) and (female symbol) G8 (Smena 7) with subsequent selection of the desired ANIMAL HUSBANDRYIt has been found that ...