Evaluation of layer type chickens under reciprocal recurrent selection

Abstract

Matings within pure male and female lines, and between pure male and female lines were carried out to produce purebred male line (AA x AA), female line (BB x BB), cross (AA x BB) and reciprocal cross (BB x AA). A total number of 364 pullets arising from 207 hens and 23 cocks in generation 1 and 440 pullets from 70 hens and 10 cocks in generation 2 under selection were monitored in individual cage units for part period of egg production up to 280 days of age. Parameters considered were age at sexual maturity (ASM), body weight at 20 and 40 weeks of age (BW 20 and BW40), egg weight average (EWTAV) and egg production up to 280 days (Egg 280). A non-significant difference among purebreds but a significant difference (P<0.05) between them and the crosses for all the traits considered were observed. The crosses (including the reciprocal) had lower ASM (163.10 ± 0.79 to 192.25 ± 0.4 vs 184.02 ± 1.17 to 197.99 ± 0.09 days), higher BW20 (718.61 ± 14.33 to 1477.53 ± 33.01 vs 713.17 ± 11.70 to 1173.17 ± 9.36 g) and BW40 (1858.11 ± 0.41 to 2158.26 ± 10.16 vs 1794.54 ± 32.00 to 2040.05 ± 12.93 g).They also laid heavier eggs (52.95 ± 0.30 to 55.32 ± 0.28 g) vs 52.58 ± 0.22 to 54.67 ± 0.28 g) and produced higher number of eggs up to 280days (45.09 ± 0.78 to 85.32 ± 0.70 vs 45.69 ± 0.98 to 71.62 ± 0.48), than the two purebreds, respectively. Percentage heterosis for ASM was negative for all crossbred groups and was positive for most of the other traits. Since heterosis is favourable in all the traits considered dams of the cross bred groups can be used for commercial egg production.