Articles

The duck industry makes an important contribution to the availability of animal protein sources in Egypt, little known about the genetic parameters, particularly the heritability and genetic correlations of body weight and egg production in ducks. Body weight is the most essential feature for genetic improvement due to its ease of selection, high heredity, and large impact on meat production costs. The target of this study was to evaluate and explain genetic parameters such as the heritability, the genetic and phenotypic correlations, and sire breeding value in Domyati (local) and Khaki-Campbell (foreign) ducks in order to improve body weight and egg traits. A total of 160 (80 Domyati and 80 Khaki-Campbell ducks utilized to measure body weight at 16 and 20 weeks g), as well as 7000 eggs (2500 Domyati and 4500 Khaki-Campbell) to measure egg traits (the egg number, egg weight, and egg mass are all measured throughout the first 90 days of laying). In Domyati and Khaki-Campbell ducks, the heritability estimated for body weight was moderate to high, ranged from 0.35 to 0.40, and 0.21 to 0.30 for egg production. The genetic correlations among body weight and egg traits were all positive and had high values, also among BW16 and BW20 were stronger (0.90); (0.99). So the genetic improvement in BW16 could be followed by an increase in BW20 weeks. It concluded that, the relatively high value of genetic heritability for body weights and egg traits in Domyati and Khaki-Campbell ducks, indicates that it is possible to genetically increase body weight and egg traits through selection and subsequently inbreeding to divide the herd into groups that are selected among themselves to keep their sons.

Native Middle Egypt Rabbit breed (NMER) was crossbred with Gaint Flander rabbits to create a synthetic line. This study was aimed to evaluate the genetic estimates of this synthetic line with comparing to the purebreds. A crossbreeding was carried out by mating bucks of Gaint Flander (G) with does of NMER (N) to get F1 (½N½G), then does and bucks of F1 were mated to get F2 (½N½G)2, followed by two generations of inter se-mating to get a new synthetic line is called Egy-line with a genetic structure of ((½N½G)2)2. Heritability estimates for body weights were generally moderate and ranged from 0.10 to 0.24, while the estimates of heritability for growth rate were low and moderate and ranging from 0.01 to 0.23. Common little effects of body weight were large as weaning (0.61), then declined gradually as the rabbit grew older. Also, the same trends were observed for relative growth rate (RGR). The direct additive effects were positive and highly significant for all body weights at different ages, favoring Gaint Flander and heavier comparing with NMER rabbits. Most relative growth rates during different intervals were non-significant. Gaint Flander was highly significant and heavier in maternal additive effects it in different weeks of age comparing with NMER rabbits. Direct heterosis effect for most bodyweight was positive and highly significant, and percentages of direct heterosis increased generally with the advance of age. Maternal heterosis for growth rates from 5 to 6, 8 to 10, and 10 to 12 week was positive, only. Direct recombination effects for most bodyweight were positive and highly significantly exclude weight at 5 and 6 weeks. It is concluded that a new synesthetic line (Egy-line) has proven its superiority and performance well in all different body weights and most growth rates compared to other parents and crossbreds.