Response to family selection and genetic parameters in Japanese quail selected for four week breast weight

Abstract. An experiment was conducted to investigate the effect of short-term selection for 4 week breast weight (4wk BRW), and to estimate genetic parameters of body weight, and carcass traits. A selection (S) line and control (C) line was randomly selected from a base population. Data were collected over two consecutive hatches for four generations. A total of 1 135 records from 156 sires and 218 dams were used to estimate the genetic parameters. The genetic improvement of 4wk BRW was 3.5, 2.7 and 0.6 g in generation 2, 3 and 4, respectively. The estimated heritability by using pedigree information was 0.35±0.06. There were a significant difference for BW, and carcass weights but not for carcass percent components between lines (P<0.01). The heritabilities and correlated responses for body weight (BW), carcass and leg weights were 0.46, 0.41 and 0.47, and 13.2, 16.2, 4.4 %, respectively. The genetic correlations of BRW with BW, carcass, leg, and back weights were 0.85, 0.88 and 0.72, respectively. Selection for 4 wk BRW improved feed conversion ratio (FCR) about 0.19 units over the selection period. Inbreeding caused an insignificant decline of the mean of some traits. Results from this experiment suggest that BW as a genetically correlated trait can be used to improve BRW.