Estimation of genetic parameters for body weight and egg production traits in Mazandaran native chicken

2012 ◽  
Vol 44 (7) ◽  
pp. 1437-1443 ◽  
Author(s):  
Shahram Niknafs ◽  
Ardeshir Nejati-Javaremi ◽  
Hassan Mehrabani-Yeganeh ◽  
Seyed Abolghasem Fatemi
Keyword(s):  
Body Weight ◽  
Egg Production ◽  
Genetic Parameters ◽  
Production Traits ◽  
Native Chicken ◽  
Estimation Of Genetic Parameters

Reduced-rank estimation of genetic parameters for egg production traits and cluster analyses with predicted breeding values

2018 ◽  
Vol 68 (2) ◽  
pp. 81-86
Author(s):  
Luara Afonso de Freitas ◽  
Rodrigo Pelicioni Savegnago ◽  
Natalia Vinhal Grupioni ◽  
Salvador Boccaletti Ramos ◽  
Nedenia Bonvino Stafuzza ◽  
...  
Keyword(s):  
Egg Production ◽  
Genetic Parameters ◽  
Production Traits ◽  
Breeding Values ◽  
Cluster Analyses ◽  
Rank Estimation ◽  
Reduced Rank ◽  
Estimation Of Genetic Parameters

scholarly journals GENETIC AND PHENOTYPIC ASSOCIATIONS OF JUVENILE BODY WEIGHTS AND EGG PRODUCTION TRAITS IN TWO STRAINS OF RHODE ISLAND CHICKENS

2021 ◽  
Vol 18 ◽  
pp. 66-70
Author(s):  
O. O. ONI ◽  
B. Y. ABUBAKAR ◽  
S. O. OGUNDIPE
Keyword(s):  
Body Weight ◽  
Rhode Island ◽  
Sexual Maturity ◽  
Egg Production ◽  
Genetic Parameters ◽  
Laying Hens ◽  
Genetic Correlations ◽  
Selection Criterion ◽  
Production Traits ◽  
Body Weights

Data on body weight at 16 (WT16); 20 (WT20) weeks of age and at sexual maturity (WTSM) weight of first egg (WT1st), age at sexual maturity (ASM) and 120-d egg production (EN)  were used to estimate genetic parameters in 636 hens of two strains of Rhode Island chikens. There were significant (P.01) differences between  the two strains for all traits except for WTSM.The heritability estimates obtained ranged from 0.05 to 0.41 and 0.04 to 0.30 for strains 1 and 2 respectively. The genetic correlations obtained for the various traits were medium to high for the two strains. The phenotypic correlations were generally low but followed the same trend. The results indicate that selected stocks of the two strains would show improvements in egg production and age   at sexual maturity if juvenile body weight (WT20) is employed as a selection criterion at housing for laying hens.

scholarly journals Determination of the best model for estimation of genetic parameters on the Fars native chicken traits using Bayesian and REML methods

Genetika ◽  
2018 ◽  
Vol 50 (2) ◽  
pp. 431-447
Author(s):  
Ali Mohammadi ◽  
Yousef Naderi ◽  
Reza Nabavi ◽  
Fatemeh Jafari
Keyword(s):  
Body Weight ◽  
Bayesian Approach ◽  
Bayesian Method ◽  
Genetic Parameters ◽  
Genetic Parameter ◽  
Correlation Coefficients ◽  
Native Chicken ◽  
Egg Number ◽  
Estimation Of Genetic Parameters

This study was conducted to determine the best model for genetic parameter estimation on the Fars native chicken traits using Bayesian and REML Methods. Studied traits were body weight at first day (BW1), body weight at eighth weeks (BW8), body weight at 12th weeks (BW12), age at sexual maturity (ASM), egg number production (EGP) and mean egg weight during 28th ,30th and 32nd week ages (EGW) involving three generations 17, 18 and 19 during the years 2010 to 2012. Genetic parameters were estimated with REML method using WOMBAT software and with Bayesian approach using MTGSAM software. Based on AIC and DIC criteria, the most appropriate model was determined. Estimations of direct additive heritabilities for BW1, BW8, BW12, ASM, EGP and EGW by the best models using REML method were 0.31, 0.32, 0.29, 0.45, 0.24 and 0.22 and by Bayesian method were 0.36, 0.33, 0.30, 0.48, 0.26 and 0.25, respectively. The genetic correlation coefficients ranged from -0.709 between EGP and ASM to 0.844 between BW8 and BW12 (by Bayesian method) and ranged from -0.724 between ASM and EGP to 0.894 between BW12 and BW8 (by REML method). Generally, based on the employed criteria, the 1st and 2nd models can be suggested for analysis of body weight traits (BW1, BW8 and BW12), whereas for other traits (ASM, EGP and EGW), 1st, 5th, 4th and 6th models seems to be suitable for estimation of genetic parameters of the Fars Native fowls traits using Bayesian and REML Methods. The Bayesian approach recommended for estimation of genetic parameters on the Fars native chicken traits because this method used the prior distribution in the calculation process.

scholarly journals DOMINANCE AND EPISTASIS IN HETEROSIS OF WHITE LEGHORN STRAIN CROSSES

1987 ◽  
Vol 67 (3) ◽  
pp. 663-680 ◽  
Author(s):  
R. W. FAIRFULL ◽  
R. S. GOWE ◽  
J. NAGAI
Keyword(s):  
Body Weight ◽  
Sexual Maturity ◽  
Egg Production ◽  
Significant Contribution ◽  
Production Traits ◽  
White Leghorn ◽  
Cross Combination ◽  
Commercial Strain ◽  
Better Than

Four unrelated pure strains of White Leghorns including a grandparent strain from industry and 12 two-strain, 24 three-strain, 24 four-strain and 12 F2 strain crosses produced contemporaneously were used to examine the role of dominance and epistasis in heterosis. A control strain and a commercial strain were also included. For egg weight, the heterosis observed closely approximated that expected due to dominance alone. For sexual maturity and body weight, dominance was the major component of heterosis, but epistasis made a significant contribution — additive by additive (A × A) genetic effects for sexual maturity and 140-d body weight, and parental epistasis for mature body weight. Both dominance and epistasis played a significant role in heterosis for egg production traits. A × A, dominance by dominance (D × D) and additive by dominance (A × D) epistasis were all important for hen-housed egg production and hen-housed egg yield. For hen-day rate of egg production, A × A epistasis was significant only early in the laying year (to 273 d), A × D and D × D were significant to 385 d and in the full year (to 497 d); however, none (A × A, A × D and D × D) was significant near the end of lay (386–497 d). Overall heterosis estimates for full year egg production measured as hen-housed egg production to 497 d or hen-day rate from housing to 497 d clearly showed that on average two-strain crosses were superior to three-strain crosses which were superior to four-strain crosses which in turn exceeded the F2 crosses. Nevertheless, several three-strain crosses had performance for egg production that was equal to or better than the two-strain cross with the highest egg production. Thus, in commerce, where the level of egg production is of great economic importance, the testing and use of a specific three-way cross combination will usually result in a better commercial product. Key words: Heterosis, egg production genetics, epistasis, stocking rate, strain cross, White Leghorn

scholarly journals Performance Evaluation of Kuroiler and Sasso Chicken Breeds Reared under On-farm and On-station Management Conditions in Tanzania

2021 ◽  
Vol 3 (2) ◽  
pp. 53-59
Author(s):  
Fadhili S. Guni ◽  
Said H. Mbaga ◽  
Andalwisye M. Katule
Keyword(s):  
Body Weight ◽  
Egg Production ◽  
Linear Models ◽  
Farm Management ◽  
General Effect ◽  
Production Traits ◽  
Gxe Interaction ◽  
Live Body Weight ◽  
Egg Production Rate ◽  
On Farm

A study was conducted to evaluate the effect of management, breed, and their interaction on growth performance, egg production, and survivability under on-station and on-farm management conditions in Tanzania. A total of 1200 chicks, 600 for each breed, Kuroiler, and Sasso of mixed sexes were used. Birds under on-station management were confined and fed commercial ration throughout the experiment while those under on-farm management were allowed to semi-scavenge and supplemented with available feeds in the household. Brooding was carried out on-station for six weeks. Thereafter, birds were sub-divided for on-station and on-farm evaluation where data on body weight, egg production traits, and survival rate were taken at different ages from week 6 up to 52. The General Linear Models procedure fitting management, breed, and interaction between management and breed was used to analyze the data. Results show that management conditions had a significant influence on the performance of the breeds. Birds reared on-station performed better in all traits measured than those reared on-farm. The general effect of the breed was significant only for hen-day egg production (HDEP %) and hen-housed egg production (HHEP) in favour of Sasso chickens. Similarly, Sasso was more efficient at converting feed to live body weight. Interactions between management and breed were observed for all traits except peak egg production rate and mortality rate. While Sasso performance was better than that of Kuroiler on body weight, age at first egg, HDEP, age at peak egg production, and HHEP under the on-station management system, their performance in these traits were similar under the on-farm management except for body weight and age at first egg where Kuroiler was superior to Sasso. The survivability was also higher for Kuroiler than for Sasso under both management systems. It is concluded that genotype by environment (GxE) interaction had significant effects on the performance of the two breeds thus, a need to consider such effect when promoting them for either on-station or on-farm rearing.

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