Summary and conclusion
The present study has been carried out at the Poultry Production Experimental Station, Faculty of Agriculture, Suez Canal University, Ismailia, Egypt. In an experiment to evaluate the performance of some three and four way crosses in both body weight and egg production traits. The following results were obtain.
Body weights:
1-a- The analysis of variance of the data showed differences among genotypes in body weights, also differences were appearances between sexes at all study ages but no difference between the tow sexes in hatch weight. In three way crosses experimental RR had the heaviest body weight and the cross RDL showed superiority from 0 to 12-15 wk of age in males. In females there were no significant differences between RR and RLF which had heaviest body weight from 15 to 21 wk of age.
1-b- In four way crosses in both males and females the cross FRLD showed the heaviest body weight followed by FRDL. Generally Dandarawi had the lowest body weight in both experiments.
2-a- The cross RLF had the best growth rate at all study periods in males and RFL showed the best one in females.
2-b- The crosses FRDL and FRLD showed the highest growth rate from 0-3 wk of age. But SLFR showed the highest growth rate from 9-12 wk of age in males. In females the cross FRDL showed the highest growth rate from 0-6 wk of age and the cross SLRF showed the highest growth rate at 12 wk of age, while DD and LL showed the highest growth rate from 18-21 wk of age.
3-a- In heterosis of body weight of the three way crosses the cross LFD had the highest heterosis in males and RDS had the highest heterosis in females.
3-b- In heterosis of body weight of the four way crosses the cross FRLD had the highest heterosis in both males and females.
Measurements of sexual maturity and egg production:
4-a-The analysis of variance of the data showed differences among genotypes in sexual traits. in three way crosses the cross SRL had the heaviest body weight at sexual maturity and the longest Shank, RDS had the smallest age at sexual maturity and biggest wattle, and RFL had the longest keel and comb.
4-b- In four way crosses FRDL had the heaviest body weight at sexual maturity, while FRLD had the longest Shank and keel and the cross SLFR had the smallest age at sexual maturity. LL had the longest comb and wattle.
5-a- The analysis of variance of the data showed differences among genotypes in egg production traits but not in 90 day egg production. In three way crosses LL had the highest 120 day egg number, 120 day egg mass and 90 day egg mass. While RR had the heaviest egg weight.
5-b- In four way crosses the cross DRSL had the highest 120 day egg number, while FRLD had the highest 90 and 120 day egg mass. And RR had the heaviest egg weight.
6-a- In three way crosses the cross SRL had the higher heterosis in egg weight at 90 and 120 day of age. And RDF had the higher heterosis in egg number and mass at 90 and 120 day of age. the lowest heterosis in sexual age found in RDS.
6-b- In four way crosses the cross FRLD had the higher heterosis in egg weight and mass at 90 and 120 day of age. And SLFR had the higher heterosis in egg number at 90 and 120 day of age, and the lowest heterosis in sexual age. While FRDL had the higher heterosis in maturity weight.
Correlation Coefficient:
7-a- In three way crosses the highest phenotypic correlation was estimated between 18 and 21 wk body weight and the highest genetic correlation was estimated between 18 and 12, 6, and 9 wk body weight.
7-b- In four way crosses the highest phenotypic correlation was estimated between 18 and 21 wk body weight and the highest genetic correlation was estimated between 12 and both 9 and 18 wk body weight.
8-a- In three way crosses the highest genetic correlation was estimated between sexual weight and both shank length and Comb high, between comb length and wattle, 90 and 120 egg number. The highest phenotypic correlation was estimated between 90 and 120 egg mass.
8-b- In four way crosses the highest genetic correlation was estimated between shank length and both Comb high and egg weight. Between keel length and 90 and 120 egg number and weight. The highest phenotypic correlation was estimated between 90 and 120 egg weight.
Heritability estimates:
9-a- In three way crosses the highly heritability estimated from dam component was estimated to body weight at 3 wk of age.
9-b- In four way crosses the highly heritability estimated from dam component and from dam+sire was estimated to hatch weight, and 3 wk from sire component.
10-a- In three way crosses the highly heritability estimated from dam component was estimated to keel length.
10-b- In four way crosses the highly heritability estimated from dam component and from dam+sire was estimated to sexual maturity age, and sexual weight from sire component.
Generally RR and FF gives us an ideal example to produce crosses, we can use any of the tow strain to improve body weight and egg production. The crosses FRDL and FRLD showed good performance in four way crosses in both body weight and egg production.