Effect of Selection for Body Weight on Body Measurements and Carcass Traits in El-Salam Strain of Chicken in Egypt

Abstract

This work was carried out at Sakha, Poultry Production Research Station, Animal Production Research Institute, Ministry of Agriculture, during three successive generations to study the effect of the individual selection for high body weight at marketing age (12 weeks) on body measurements (shank length, keel length and body circumference), carcass traits (dressing, breast meat, thigh meat percentage, giblets, and offal percentages of live body weight) in El-Salam strain of chicken. Also, estimates of the genetic parameter for these studied traits. A total number of 789 pedigreed birds obtained from 697 dames mated by 92 sires through three successive generations. The chicks in each generation divided into two lines, first is the selected line and second is the control line. The pullets were transferred to individual laying cages until the end of production phase. Artificial insemination was used during the production season by eight females to each male. In base and later generation, checks were selected according to body weight as equal or greater than average of the flock at 12 weeks of age. Number of 36 checks (18 males and 18 females; 6 from each generation) from selected line and 18 checks (9 males and 9 females; 3 from each generation) from the control one at 12 weeks of age were slaughtered to measure the previous carcass traits. Results showed that body weight at 12 weeks of age, increased (p˂0.05) by generations in selected line more than the control line. Also, there were significant differences between generations, lines and sex in body weight and body measurements such as shank length, keel length and body circumference. Selected and unselected males were better than females within and between lines for the most of the studied traits. Chicken males had higher body weight than females in all generations. There were significant differences between generations, lines and sex in carcass traits [dressing, breast meat, thigh meat, giblets (gizzard, heart, and liver) and offal (blood, head, wings, shanks, feather, and viscera) percentages]. Heritability estimates for body weight, shank length, keel length and body circumference at 12 weeks of age were 0.55, 0.44, 0.51 and 0.48, respectively. Heritability estimates for dressing, breast meat, thigh meat, giblets, and offal percentages were 0.48, 0.47, 0.45, 0.52 and 0.47, respectively. All genetic correlations among body weight, body measurements, and carcass traits were positive, ranging from 0.11 to 0.91. All phenotypic correlations between different studied traits were positive ranging between 0.29 and 0.43. It could be concluded that the selection should be carried out to improve body weight, body measurements and carcass traits at marketing age (12 week) in El-Salam strain of chicken in Egypt.

Direct Response Due to Selection for Body Weight at Eight Weeks of Age in Dandarawi Chicken: Body Weight and Conformation.

“…The interactions generation x line x sex were not significant when considering shank length at all ages of the study. This result agreed with Abdellatif (1999); Abd El-Karim and Ashour (2014). From the significant interactions between the main effects, it could be said that there were other factors affecting on the different variables than the main effects, where theinsignificant interactions showed that the main effects affected directly on the studies traits.…”

“…Also, it was noticed that the selected line had superior shank length compared with control line at 4, 8, 12, 16 and 20 weeks of age and it increased gradually in linear manner (Figure 2). These results are in full agreement with Abdellatif (1999); El-Wardany (1999); Abd El-Ghany (2006); Khalifa (2007); Abd El-Karim and Ashour (2014) and Ramadan et al (2014). Regardless of sex, generation x line interaction was highly significant (P≤0.01) at 4, 12, 16 and 20 weeks of age.…”

“…Body weight is usually consideringa fair indicator for subsequent growth rate (Chambers, 1990). As reported before in different selection programs, there were significant differences between lines selected for high and low body weight at 8 weeks of age (Maloney et al 1967;Marks, 1983;Liu et al 1995;Abdellatif, 1999;EL-Dlebshany, 2004;Abd El-Karim and Ashour, 2014;Ashour et al 2015and Abou El-Ghar andAbd El-Karim, 2016). As for the effect of sex on body weight (Maloney et al 1967;Jaap, 1971;Soltan andEL-Nadi, 1986 andAbdellatif, 1989) reported that the males body weight at 8 weeks of age was superior that of females with significant differences.The individual selection is effective for certain traits that exhibited high heritability estimates such as body weight (Rishell, 1997).Many of body conformation measurements such as shank and keel lengths may be used as good indicators for skeletal size, where Chambers(1990) stated that there were genetic relationship between growth and skeletal dimensions.Normally the sexual dimorphism occurs in the majority of the domesticated avian species, especially in the chickens where the males were found to be heavier than females by about 10-20% as Merritt (1966) and Buvanendran (1969).…”

“…4-Shank length (SL):Least square meansof shank length (cm) of males and females for both selected and control lines in the two generations at 4, 8, 12, 16 and 20 weeks of age are presented inTable(6). The results showed that there were highly significant differences between generations, lines and sexes (P≤0.01) at 4,8, 12, 16 and 20 weeks of age (Table 7).This result in harmony with Abdellatif (1999); Khalifa (2007); Abd El-Karim and Ashour (2014) and Abou El-Ghar and Abd El-Karim (2016). The selected line had longer shank length than the control line over generations (Table 6).…”

EFFECT OF SELECTION FOR BODY WEIGHT ON EGG PRODUCTION, EGG QUALITY, FERTILITY AND HATCHABILITY TRAITS in EL-SALAM CHICKEN STRAIN IN EGYPT

“…Selection for body weight is the most important traits of genetic improvement program because that body weight is easily measured and correlated with several other traits (Abd El-Ghany 2005, Kosba et al, 2002, Ghanem, et al, 2007, Saleh, et al, 2008, Abd El-karim and Ashour 2014, and Ramadan, et al, 2014.…”