Department of Livestock Production and Management College of Veterinary Science, Rajendranagar, Hyderabad - 500 030 (AP)
1 Corresponding author: PVP No.3, Chitlapakam, Chennai, Tamil Nadu 600 004.
* Part of M V Sc Thesis submitted to Acharya N G Ranga Agricultural
Data collected on 1522 pullets of IWD strain and 899 pullets of IWF strain of White Leghorn were utilized for the study. The hen housed eggs production was partitioned into 5 parts viz., 21–28 weeks, 21–32 weeks, 21–36 weeks, 21–40 weeks and 21–64 weeks. Least square means of age at first egg, part period egg production up to 40 weeks and annual egg production up to 72 weeks was found to be 148 days, 110 eggs and 264 eggs, respectively in IWD strain and 155 days, 97.34 eggs and 276.62 eggs, respectively in IWF strain. The heritability estimates from the corresponding traits were 0.29±0.09, 0.31±0.09 and 0.08±0.05, respectively in IWD stain and 0.27±0.10, 0.12±0.07 and 0.06±0.07, respectively in IWF strain. Age at first egg showed negative and significant genetic and phenotypic correlations with various part periods and annual egg production in both the strains. The various part record egg production exhibited significant positive genetic and phenotypic correlations with annual egg production. The relative efficiency of selection to improve annual egg production per unit time was found to be the most efficient during P5 (21–64 weeks) in IWD and during P3 (21–36 weeks) in IWF strains, respectively.
Correlation, part period egg production, relative efficiency, selection
