Short term selection response for higher 52 week egg mass based on Osborn index in Vanaraja female parent line chicken

Abstract

Short term selection response for egg mass at 52 weeks of age (EM52), the primary trait of selection and the correlated response of other production traits was evaluated utilizing the last five generations data of Vanaraja female line (PD-2) at ICAR-Directorate of Poultry Research, Hyderabad, Telangana. The phenotypic and genetic response for EM52 was significant (P≤0.05) with a magnitude of 341.9 and 237.4 g per generation, respectively. The correlated response of egg production at 52 weeks was also significant (P≤0.05) with 5.68 and 4.37 eggs per generation on genetic and phenotypic scale, respectively. The age at sexual maturity reduced over the generation in a desired direction. The least square means (LSMs) for production traits (EM52, EP52, EW52, EP 40 and ASM) varied significantly (P≤0.05) across the generations. The LSMs of EM52 (7898±2.01 g) and EP52 (138.60±0.03 eggs) were significantly higher in S-5 generation. Selection intensity (i) ranged from 0.44 to 1.10 and the rate of inbreeding was 0.003. Realized and estimated heritabilities of EM52 were 0.04 and 0.11, respectively. The significant improvement in primary trait and other important correlated traits indicated the effectiveness of Osborn index selection in PD-2 line, which will contribute to the improvement in egg production and egg weight in terminal cross Vanaraja chicken variety.