This work was carried out at Sakha Poultry Production Research Station, Animal Production Research Institute, Ministry of Agriculture, during two successive generations in order to estimate the correlated response in egg production, egg quality and hatch traits to selection for body weight at 12 weeks of age in El-Salam chicken strains. Traits under taken were body weight, egg number, egg weight, egg mass, egg quality, fertility. Heritability, genetic and phenotypic correlations among studied traits were estimated. The means of body weight at 12 week of age in El-Salam chicken strain in the base, first and second generations for males were 868.3, 903.6 and 942.9 g and for females were 838.6, 868.3 and 881.3g for selected line, respectively. Moreover, males and females in the selected line were heavier than corresponding birds in the control one for all generations. After two generations selected for body weight, selected line was significantly higher body weight than control line by 85.4 and 33.6g in average means 9.8% and 4.0% superiority for male and female respectively. Selection to the weight of the body lead to the delayed age at sexual maturity, as well as increased body weight at sexual maturity and the period until the first ten eggs. Means of egg number and feed conversion were significantly reduced by generations. Moreover, egg weight and egg mass for selected line were significantly heavier than those of the control one. As generational succession caused significant improvements on Haugh units, it decreased egg shape index, shell thickens, albumen and yolk percentages. Furthermore, egg shape index and shell percentage were significantly (P<0.05) affected by lines. Also, data showed no significant interactions between generations and lines on all of tested egg quality traits. Reproductive performance as fertility and hatchability percentages were significantly (P≤0.05) reduced by-2.9 vs.-0.6% after progress two generation of selection, but not affected by lines separately or as combination with generations. Heritability estimated for body weight at 12 week of age were 0.67 based on sire variance component (h 2 s). Negative genetic and phenotypic correlations were found between body weight at 12 week of age with egg number, egg mass, fertility, hatchability, egg shape index, yolk%, shell% and shell thickens, while the positive effect were found for body weight at sexual maturity, age at sexual maturity, the period until the first 10 eggs, egg weight, feed conversion, albumen % and Hough unit.
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.
This study was conducted to characterize semen traits (ejaculate volume (VOL), mass motility (MM), sperm livability (LS), percentage of abnormal sperms (AS), and sperm concentration (CONC)) of Egyptian buffalo bulls and evaluate the importance of some nongenetic factors (year (YC) and season (SC) of semen collection and age of bull genetically and environmentally at collection (ABC)) affecting the investigated traits. A total of 7761 normal semen ejaculates were collected from 26 bulls from 2009 to 2019. Single-trait and bivariate repeatability animal models using Bayesian methods were used to estimate variance components, heritability, repeatability, and genetic correlations among the investigated semen traits. YC and ABC exerted significant effects on most semen traits, whereas SC exerted no significant effect on all the investigated semen traits. Heritability estimates were 0.08, 0.52, 0.51, 0.04, and 0.49 for VOL, MM, LS, AS, and CONC, respectively. Repeatability estimates were 0.14, 0.82, 0.79, 0.06, and 0.78 for VOL, MM, LS, AS, and CONC, respectively. The genetic correlations between MM and each of LS and CONC were highly significant (0.99 ± 0.01 and 0.95 ± 0.14, respectively), and that between LS and CONC was also highly significant (0.92 ± 0.20). The high heritability estimates for MM, LS, and CONC combined with the favorable high significant genetic correlations between these traits indicated that direct selection for MM may be an effective method to enhance semen quality in Egyptian buffalo bulls and consequently improve fertility.
Objective: The objectives of the current study were to study the main environmental factors affecting birth weight (BW) and weaning weight (WW), estimate variance components, genetic parameters and genetic trend and to evaluate the variability and relationships among breeding value of BW and WW using principal components analysis (PCA).Methods: A total of 16,370 records were collected from 8,271 buffalo calves. Genetic parameters and breeding values were estimated using a bivariate animal model which includes direct, maternal and permanent maternal effects. These estimates were standardized and used in PCA.Results: The direct heritability estimates were 0.06 and 0.41 for BW and WW, respectively whereas direct maternal heritability values were 0.03 and 0.14, respectively. Proportions of variance due to permanent environmental effects of dam were 0.455 and 0.280 for BW and WW respectively. The genetic correlation between BW and WWs was weak approaching zero, but the maternal correlation was 0.26. The first two principal components (PC1 and PC2) were estimated utilizing the standardized breeding values according to Kaiser method. The total variance explained by the first two PCs was 71.17% in which 45.91% and 25.25% were explained by PC1 and PC2, respectively. The direct breeding values of BW were related to PC2 but those of WW and maternal breeding values of BW and WWs were associated with PC1.Conclusion: The results of genetic parameters and PCA indicate that BW and WWs were not genetically correlated and improving growth traits of Egyptian buffaloes could be achieved using WW without any adverse effect by BW.
Aim of this study is to evaluate the effect of adding different levels of Zinc and Selenium on extender as antioxidants to improve Friesian-bull semen quality after cryopreservation. Semen was collected, pooled, and extended with five treatment extenders, including control without (E1), 0.3 mg/100ml Zn (E2), 0.6 mg/100ml Zn (E3), 0.2 mg/100ml Se (E4), and 0.5 mg/100ml Se (E5). Semen was evaluated for visual parameters after dilution, equilibration, and thawing. Also, semen was evaluated by CASA only after thawing. Results showed that there are no effects of all additives on sperm characteristics after dilution and thawing. Only visual progressive motility percentage increased (P<0.05) post-equilibration by E5. Percentages of acrosome integrity were enhanced by E4 and E5. Semen analysis by CASA revealed that non-motility, and total and head abnormalities percentages were decreased (P<0.05), while vitality, and total and rapid progressive motility percentages were increased (P<0.05) by E5. Dynamic sperm parameters straightness and wobble) were increased (P<0.05) E5. In conclusion, adding selenium at a level of 0.5 mg/100ml to extender of cryopreserved Friesian-bull semen ha beneficial effects on maintaining sperm parameters and improved sperm freezability. This may be used as a tool for improving cryopreserved semen in artificial insemination centers.
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