EFFECT OF REPEATED BACKCROSSING FOR TWO GENERATIONS BETWEEN THE LOCAL BLACK BALADI AND WHITE NICHOLAS TURKEYS ON CARCASS TRAITS.

Effect of repeated backcrossing between the local Black Baladi (BB) and White Nicholas (WW) turkeys for two generations were carried out to estimate body weight at 4, 8, 12, 16, and 20 weeks of age, body measurements at16 weeks of age (BM). Also effect on absolute and relative (percentages ) weights of dressing, eviscerated carcass, wings, neck, head, liver, gizzard, giblets, breast, thigh, back, and edible parts was studied. Economical evaluation for edible meat part was studied. Moreover, Strait-bred differences, direct additive and maternal effects and heterosis percentages were estimated. Results can be summarized as follows: 1- The body weight, body measurements, absolute and relative weight of the different carcass traits were significantly (P<0.001) affected by repeated backcrossing where highly significant differences among the different genotypes and between the two sexes were found. The WW variety and backcross of 7/8W × 1/8B had significantly the highest values for most studied trait. 2- The values of maternal additive and direct additive effect showed that using 3/4W×1/4B poults as a dam with WW toms as a sire-breed gave an advantage in performance concerning body weight at the different studied ages, body measurements and most of the carcass traits than its reciprocal mating. 3- Positive heterotic percentages effects were estimated for body weights at 4, 8, 12, 16, and 20 weeks of age (26.0%, 19.9%, 8.7%, 8.5% and 9.9%, respectively). Estimates for body conformation were low and varied between positive for shank length and keel length and negative for the two breast measurements. 4- The WW pullets had the best feed conversion (FC) followed by both backcrosses while, the BB pullets had the lowest FC value. The WW had the lowest price cost of kilogram for edible parts followed by the two backcrosses but the BB variety had the highest cost of edible parts. Generally, the price of a kilogram of black feathers turkeys(Like BB and repeated backcrosses turkeys) was more expensive than the price of White feathers turkeys (like WW turkeys) in Egypt by approximately10 to 20%. It could be concluded that backcrosses between White Nicholas variety of turkey as a sire parent with 3/4Wx1/4B cross as a dam parent improved body weights at the different studied ages, the different body measurements, feed conversion and edible carcass parts. Moreover, backcrosses that produced progenies which have a black feather, had more acceptability by consumers in Egypt and had more expensive price than birds of White Nicholas. [ABSTRACT FROM AUTHOR]