scholarly journals Estimation of genetic parameters of egg production traits of laying hens by restricted maximum likelihood applied to a multiple-trait reduced animal model

1992 ◽  
Vol 24 (6) ◽  
pp. 539 ◽  
Author(s):  
B Besbes ◽  
V Ducrocq ◽  
JL Foulley ◽  
M Protais ◽  
A Tavernier ◽  
...  
Keyword(s):  
Animal Model ◽  
Maximum Likelihood ◽  
Egg Production ◽  
Genetic Parameters ◽  
Laying Hens ◽  
Restricted Maximum Likelihood ◽  
Production Traits ◽  
Multiple Trait ◽  
Reduced Animal Model ◽  
Estimation Of Genetic Parameters

scholarly journals Estimation of Genetic and Phenotypic Parameters for Udder Morphology Traits in Different Dairy Sheep Genotypes

2017 ◽  
Vol 65 (1) ◽  
pp. 105-110
Author(s):  
Pavol Makovický ◽  
Milan Margetín ◽  
Peter Makovický
Keyword(s):  
Animal Model ◽  
Maximum Likelihood ◽  
Genetic Parameters ◽  
Genetic Correlations ◽  
Restricted Maximum Likelihood ◽  
Primary Data ◽  
Dairy Sheep ◽  
Multiple Trait

Knowledge of genetic parameters is the basis of sound livestock improvement programmes. Genetic parameters have been estimated for linear udder traits: Udder depth (UD), Cistern depth (CD), Teat position (TP), Teat size (TS) and external udder measurements: Rear udder depth (RUD), Cistern depth (CDe), Teat length (TL) and Teat angle (TA) – 1275 linear assessments (381 ewes) and 1185 external udder measurements (355 ewes) were included in the analysis for each character of 9 genotypes. Nine breeds and genotypes were included in these experiments: purebred Improved Valachian (IV), Tsigai (T), Lacaune (LC) ewes, and IV and T crosses with genetic portion of Lacaune and East Friesian (EF) – 25 %, 50 % and 75 %. Primary data were processed using restricted maximum likelihood (REML) methodology and the multiple‑trait animal model, using programs REMLF90 and VCE 4.0. High genetic correlations were found between UD and RUD (0.86), CD and CD(e) (0.93), TP and TA (0.90), TS and TL (0.94). The highest heritabilities were estimated for exact measurements of TL and CD (0.35–0.39) and subjectively assessed TA and TS (0.32 – 0.33).

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.

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