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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. The phenotypic and genetic response for EM52 was significant 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 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 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.

Vanaraja female line (PD-2) chicken was evaluated for growth, production, carcass and egg quality traits utilizing the data generated from 3,737 chicks and 599 hens produced in pedigreed mating with 50 sires and 250 dams at ICAR-Directorate of Poultry Research, Hyderabad, Telangana. Fertility was 86.63% and the hatchability was 86.72% on fertile egg set and 72.53% on total egg set basis in PD-2 line. The least squares means (LSM) for six week body weight and shank length were 662.38±2.54 g and 71.48±0.12 mm, respectively. Sex had significant influence on live weight, thigh and wing proportions wherein cocks had heavier and stronger legs and wings. Abdominal fat was significantly higher in females. The egg production up to 40 and 52 weeks of age was 80.29±0.03 and 133.16±0.05 eggs, respectively. The egg mass up to 52 weeks of age was 7447.41±2.98 g in PD-2 line. The heritability was low up to 15% for egg production and 17% for egg mass, the primary trait of selection in PD-2 line. Egg mass and egg weights at different ages had positive association as larger and high number of eggs contributed more to the egg mass. The egg mass and egg production had a significant positive association in PD-2 line. The egg quality was reasonably fair with average shape index of 75.22 and Haugh unit of 79.0±0.62. The albumen, yolk and shell weights were 30.20±0.14, 15.8±0.09, 0.40±0.02 g, respectively. The proportion of heritability and the magnitude of association between the important traits provide requisite information for implementing the breeding program for improvement of egg production in PD-2 line.

A comprehensive study was carried out in Gramapriya female line (PD-3) with respect to growth, production, selection response and population structure utilizing the data generated for the last 7 generations at ICAR-Directorate of Poultry Research, Hyderabad, Telangana. The average fertility was 71.89% and hatchability was 80.52% on fertile egg set and 57.08% on total egg set. The least squares means (LSMs) for body weight at 4 and 6 weeks of age were 168.06±0.01 and 320.10±0.02 g, respectively. The heritability estimates from sire and dam components of variance were moderate to high for both body weight and shank length (0.27 to 0.35). The correlation coefficients (genetic and phenotypic) between body weights and shank length were positive and high in magnitude except with day old body weight. Age at sexual maturity (ASM) was 171.47±0.01 days in PD-3 population. The part period egg production (EP 40) at 40 weeks of age was 75.60±0.01 eggs with an egg mass (EM 40) of 4,157.19±0.99 g. The h2 estimates for ASM, EW 40, EP 40 and EM 40 were 0.16±0.07, 0.42±0.11, 0.18±0.07 and 0.15±0.06, respectively, which were moderate to high in magnitude. The egg production at 40 weeks of age was negatively associated with ASM, body weight and egg weight at different ages. Egg mass had significant positive association with egg production and egg weight at 40 weeks of age. The selection intensity (i) ranged from 0.32 to 0.85 while, rate of inbreeding ranged between 0.0031 and 0.0033 in PD-3 line. The direct selection response was 151.54 g on genetic scale and 79.75 on phenotypic scale for primary trait of selection, EM 40 over the last 7 generations. Realized and estimated heritability estimates were 0.29 and 0.15, respectively for EM 40. The study concluded that, PD-3 population was in ideal condition with respect to growth and production performance. Positive selection response for primary trait EM 40 was observed in the population maintaining both egg production and egg weight, the important traits for sustainable rural poultry farming.

Traditionally, heritability has been estimated by correlations of close kin. It is likely to be biased by determinants such as non genetic factors, inbreeding, selection and shared environment. Whereas, an animal model takes into account all relationships in a pedigree and is therefore expected to provide estimates of quantitative genetic parameters with higher precision. Therefore, the egg production data in the current study was analyzed using animal model to have more precise and accurate estimates of genetic parameters. The heritability of growth and egg weight traits was moderate to high. Whereas the heritability was lower for egg number and ASM traits. The body weights were positively correlated with egg weights and negatively correlated with egg numbers traits. The egg number produced at different age intervals was positively correlated. The genetic correlation of EP40 and EP52 with EP64 were 0.83 and 0.92, respectively. Therefore, the part period egg production of EP52 would give better selection response for egg production at 64 than EP40. Therefore, the selection of higher egg numbers can be done earlier at 52 weeks rather than waiting for EP64.