Direct and correlated responses from selection for early sexual maturity in Japanese quail

Abstract

Base population after third generation of selection conclude total number of 788 birds at 6 weeks of age were used in this study and randomly assigned to two mating groups. First groupe was selected for early age at sexual maturity (EASM) and the second was as a control line (RBC) to study the direct and correlated responses for this direct of selection. The results can be summarized as follow: 1. EASM was highly significantly (P≤0.01) decreased from 39.54 days to 35.23 days. 2. The actual and the expected selection differentials were 2.52 and 2.29g / generation. 3. The actual response to selection in the (EASM) line was1.46g /generation. a-Heritability of EASM estimated ranged from 0.29 to 0.35 b-The realized heritability ranged from 0.44 to 0.79. c-Correlated responses for EASM were as follow: d-BW0, BW2, BW4, and BW6 increased significantly (P≤0.05) from 9.95, 40.58, 98.84 and 170.47g to 10.47, 47.01, 101.87 and 181.42g. e-Egg weight (EW) was decreased (P≤0.05) from 10.74g to 10.04g. But Body weight at sexual maturity (BWSM) was increased from 136.32 g to 139.32 g. Total egg weight at first ten week (TEN10) decreased from 55.25eggs to 54.25egg. f-Fertility (FR %) was increased (P≤0.05) from 80.58% to 80.90%. and Hatchability (HA %) were increased (P≤0.05) from 70.42% to 70.92%. g-Meat, dressing and giblets % were increased significantly (P≤0.05) from 42.33, 62.04 and14.27% to 43. 76%, 63.99 and 14.99%.

Correlated Responses to Short-term Selection for Egg Production Traits in Japanese Quail

“…Ramzy et al 48 reported that cumulative selection response to selection for early sexual maturity decreased EW from 10.74 to 10.04 g but BWSM increased from 136.32 to 139.32 g after four selected generations in Japanese quail.…”

Indirect Response in Egg Production and Egg Quality Traits Due to Selection for Body Weight at 8 Weeks of Age in Dandarawi Chicken

“…The usefulness of selection procedures for improving productive or reproductive traits depends not only on the direct response itself, but also on the relevant changes in other economic traits due to the response associated with selection. However, selection for body weight may indirectly affect other traits that were not considered in the selection program because the improved trait is correlated with these traits (Abd El-Ghany, 2005;Kosba et al, 2002, andGhanem et al, 2007;Saleh et al, 2008;Abd Elkarim and Ashour, 2014;Ramadan et al, 2014;Ashour et al, 2015;and Ramzy et al, 2019).…”