Quantitative genetic analysis of some economic traits of egg type chickens
SANDEEP NARWAL, C.P.MALIK, DIDAR SINGH AND A.K.VINAYAK
Department of Animal Breeding, CCS Haryana Agricultural University
Data on 907 pullets of strain C of White Leghorn, progeny of 104 sires produced in different hatches over six generations, were used to study effect of generation and hatch within generation on performance traits. The performance traits recorded were body weight at 20 and 40 weeks of age (BW20 and BW40), age at first egg (AFE), egg production upto 40 weeks of age (EP40), egg weight at 40 weeks of age (EW40), clutch size upto 30 weeks of age (CS1) and clutch size from 31 to 40 weeks of age (CS2). Data were analysed by Harvey’s least squares technique. Heritability and correlations were estimated from sire, dam and sire + dam component of (co) variance from hatch corrected data. Generation had significant effect (P≤0.01) on all the performance traits. Least squares means for BW20, BW40, AFE, EP40, EW40, CS1 and CS2 were 1238.76g, 1510.55 g, 150.39 days, 90.31 eggs, 54.67g, 2.60 eggs and 2.51 eggs, respectively. Heritability estimates were high for AFE and EW40 and low for EP40. AFE had positive genetic (r g) and phenotypic (r p) correlation with EW40. BW20 had positive and significant r p with BW40. CS2 had positive and significant r p with BW40 and CS1. The results suggest that effect of generation should be included in the model and data should be corrected for ‘hatch effect within generation’ to get precise estimates of genetic and phenotypic (co) variability for these traits. AFE and EW40 may be improved through mass selection.