scholarly journals Heritability of egg production in laying hens under cumulative, multitrait and repeated measurement animal models

2008 ◽  
Vol 52 (No. 8) ◽  
pp. 254-260 ◽  
Author(s):  
A. Wolc ◽  
M. Lisowski ◽  
T. Szwaczkowski
Keyword(s):  
Animal Models ◽  
Variance Components ◽  
Egg Production ◽  
Genetic Parameters ◽  
Laying Hens ◽  
Genetic Effects ◽  
Repeated Measurement ◽  
Repeated Measurements ◽  
The Other ◽  
Highly Correlated

Six generations of three layer lines (13 770 recorded individuals of A22 line, 13 950 of A88, 9 351 of K66) were used to estimate genetic effects on egg production under cumulative, multitrait and repeatability models. Variance components were estimated by the AI-REML algorithm. The heritability of cumulative records ranged from 0.08 to 0.1. For the repeated measurements model the following genetic parameters were obtained: heritability 0.02–0.03, repeatability 0.04–0.38. The first two months of egg production were found to differ from the other periods: heritability was relatively high (<i>h</i><sup>2</sup> > 0.35) and low or negative correlations with the other periods were found. Heritability was low (<i>h</i><sup>2</sup> < 0.1) from the peak production until the end of recording and the consecutive periods were highly correlated. Further studies on monthly records are suggested.

scholarly journals Genetic evaluation of laying hens under fixed regression animal models

2007 ◽  
Vol 50 (3) ◽  
pp. 279-287
Author(s):  
A. Wolc ◽  
M. Lisowski ◽  
T. Szwaczkowski
Keyword(s):  
Animal Models ◽  
Akaike Information Criterion ◽  
Regression Models ◽  
Egg Production ◽  
Genetic Parameters ◽  
Laying Hens ◽  
Information Criterion ◽  
Genetic Evaluation ◽  
Term Selection

Abstract. Monthly egg production in laying hens was studied under fixed regression models. The data of 37071 birds from three strains under long term selection were analysed. The covariates from four production curves were included in nested and non-nested form. From linearized functions the model of Ali and Schaeffer most adequately described the egg production. Akaike Information Criterion favoured models with nested covariates. The following genetic parameters were estimated: heritability 0.02–0.2, 0.03–0.06, 0.03–0.20 repeatability 0.11–0.23, 0.21–0.30, 0.34–0.43 for A22, A88 and K66 lines, respectively. In conclusion, regression models could be considered in genetic evaluation of laying hens.

scholarly journals Genetic parameters for egg production and egg weight of laying hens housed in single and group cages

2002 ◽  
Vol 45 (5) ◽  
pp. 501-508 ◽  
Author(s):  
V. Nurgiartiningsih ◽  
N. Mielenz ◽  
R. Preisinger ◽  
M. Schmutz ◽  
L. Schüler
Keyword(s):  
Variance Components ◽  
Egg Production ◽  
Genetic Parameters ◽  
Genetic Parameter ◽  
Genetic Correlations ◽  
Multiple Trait ◽  
Group Cage ◽  
Egg Weight ◽  
Single Cage ◽  
Highly Correlated

Abstract. The present study was conducted to estimate the heritability and genetic correlation of monthly egg production and egg weight of 2 lines White Leghorn hens in single and group cages. A total of 2289 records (line A) and 2596 records (line D) from single cages, 518 and 541 records (for line A and D, respectively) from group cages, were analysed. (Co) variance components of single cage data were analysed using the programme VCE4 applying the REML method and a multiple trait animal model. An EM-algorithm was used to obtain (co) variance components for group cage data. Genetic correlations between single and group cages were analysed using the programme VCE4 based on sire model. Heritability estimates for monthly egg production in single cages ranged from 0.08 to 0.44 (line A); 0.04 to 0.43 (line D) and those for group cages were 0.02 to 0.42 (line A); 0.02 to 0.19 (line D). Egg weight was highly heritable for single and group cages (heritability = 0.25 to 0.54). The genetic correlations between monthly and cumulative egg production were 0.25 to 0.95 (line A); 0.26 to 0.86 (line D) for single cage and 0.24 to 0.84 (line A); 0.26 to 0.96 (line D) for group cage. Cumulative egg production in single cage were highly correlated with those of group cages (0.89 and 0.63, respectively for line A and line D). Single cage records gave higher estimates of genetic parameter than group records. However, the trend of estimates is almost the same. High genetic correlations were found between single- and group cages in most of the production periods.

scholarly journals Bayesian inference of genetic parameters for reproductive and performance traits in White Leghorn hens

2018 ◽  
Vol 63 (No. 6) ◽  
pp. 230-236 ◽  
Author(s):  
J.O. Rosa ◽  
G.C. Venturini ◽  
T.C.S. Chud ◽  
B.C. Pires ◽  
M.E. Buzanskas ◽  
...  
Keyword(s):  
Bayesian Inference ◽  
Fixed Effects ◽  
Egg Production ◽  
Genetic Parameters ◽  
Laying Hens ◽  
Reproductive Traits ◽  
A Posteriori ◽  
White Leghorn ◽  
Performance Traits ◽  
And Performance

This study estimated the genetic parameters for reproductive and performance traits and determined which ones can be used as selection criteria for egg production in laying hens using the Bayesian inference. The data of 1894 animals from three generations of White Leghorn laying hens were analyzed for fertility (FERT), hatchability (HATC), and birth rate measurements at 60 weeks of age (BIRTH), body weight at 16 and 60 weeks of age (BW16 and BW60), age at sexual maturity (ASM), egg height/width ratio, weight, and density at 28, 36, and 40 weeks of age (RHW28, RHW36, RHW40, WEGG28, WEGG36, WEGG40, DENS28, DENS36, and DENS40, respectively) traits. The genetic parameters were estimated by the Bayesian inference method of multi-trait animal model. The model included the additive and residual genetic random effects and the fixed effects of generation. The a posteriori mean distributions of the heritability estimates for reproductive traits ranged from 0.14 ± 0.003 (HATC) to 0.22 ± 0.005 (FERT) and performance from 0.07 ± 0.001 (RHW28) to 0.42 ± 0.001 (WEGG40). The a posteriori mean distributions of the genetic correlation between reproductive traits ranged from 0.18 ± 0.026 (FERT and HACT) to 0.79 ± 0.007 (FERT and BIRTH) and those related to performance ranged from –0.49 ± 0.001 (WEGG36 and DENS36) to 0.75 ± 0.003 (DENS28 and DENS36). Reproductive and performance traits showed enough additive genetic variability to respond to selection, except for RHW28. This trait alone would have little impact on the genetic gain because environmental factors would have a higher impact compared to those from the additive genetic factors. Based on the results of this study, the selection applied on the BIRTH trait can be indicated to improve FERT and HATC of eggs. Furthermore, the use of the WEGG40 could improve egg quality in this population.

Estimates of genetic parameters for growth traits of Gobra cattle

1998 ◽  
Vol 66 (2) ◽  
pp. 349-355 ◽  
Author(s):  
M. Diop ◽  
L. D. Van Vleck
Keyword(s):  
Animal Models ◽  
Maternal Effects ◽  
Genetic Parameters ◽  
Growth Traits ◽  
Random Effect ◽  
Random Effect Model ◽  
Genetic Effects ◽  
Breeding Value ◽  
Effect Model ◽  
Additive Genetic Effects

AbstractEstimates of (co)variance components and genetic parameters were obtained for birth (no. = 3909), weaning (no. = 3425), yearling (no. = 2763), and final weight (no. = 2142) for Gobra cattle at the Centre de Recherches Zootechniques de Dahra (Senegal), using single trait animal models. Data were analysed by restricted maximum likelihood. Four different animal models were fitted for each trait. Model 1 considered the animal as the only random effect. Model 2 included in addition to the additive direct effect of the animal, the environmental effect due to the dam. Model 3 added the maternal additive genetic effects and allowed a covariance between the direct and maternal genetic effects. Model 4 fitted both maternal genetic and permanent environmental effects. Inclusion of both types of maternal effects (genetic and environmental) provided a better fit for birth and weaning weights than models with one maternal effect only. For yearling and final weights, the improvement was not significant. Important maternal effects werefound for all traits. Estimates of direct heritabilities were substantially higher when maternal effects were ignored. Estimates of direct and maternal heritabilities with model 4 were 0·07 (s.e. 0·03) and 0·04 (s.e. 0·02), 0·20 (s.e. 0·05) and 0·21 (s.e. 0.05), 0·24 (s.e. 0·07) and 0·21 (s.e. 0·06), and 0·14 (s.e. 0·06) and 0.16 (s.e. 0·06) for birth, weaning, yearling and final weights, respectively. Correlations between direct and maternal genetic effects were negative for all traits, and large for weaning and yearling weights with estimates of -0·61 (s.e. 0·33) and -0·50 (s.e. 0·31), respectively. There was a significant positive linear phenotypic trend for weaning and yearling weights. Linear trends for additive direct and maternal breeding values were not significant for any trait except maternal breeding value for yearling weight.

scholarly journals Performance of Laying Hens Fed Sorghum Based Diets Supplemented with Enzymes

2021 ◽  
Vol 43 (1) ◽  
pp. 224-232
Author(s):  
O. M. Agunbiade ◽  
P. A. Onimisi ◽  
J. J. Omage
Keyword(s):  
Egg Production ◽  
Laying Hens ◽  
Egg Quality ◽  
Quality Characteristics ◽  
Egg Laying ◽  
The Other ◽  
Control Treatment ◽  
Feed Cost ◽  
Laying Performance ◽  
Dietary Treatments

Sorghum is the primary alternative feedstuff for corn in some developed countries in the production of poultry. Thus, four hundred and fifty 32 weeks old Lohmann Brown laying hens were used in a study to evaluate the effect of replacing maize with sorghum with or without enzymes supplementation, on egg laying performance and egg quality characteristics of laying hens. Birds were distributed randomly into six dietary treatments with three replicates per treatment, each replicate had 25 birds with uniform initial group weights. The treatments included maize without enzymes (T1); sorghum without enzymes (T2); as controls respectively, while T3, T4, T5, and T6 contained sorghum based diets with phytase, protease, G2G, and a combination of protease and G2G respectively. Laying performance, cost of production, and egg quality characteristics were determined for the period of the trial, 33-56 weeks of age of the birds. All data obtained were subjected to analysis of variance, using the completely randomized design (CRD) and significant differences among treatment means were compared using the Tukey test. Significant (p<0.05) differences were observed among dietary treatments but with no defined trend observed for egg production traits. Daily feed intake was significantly (p<0.05) higher in maize control diet compared to the other treatments. Diets supplemented with phytase (T3), protease (14), and combination of protease and roxazyme G2G (T6) had significantly (p<0.05) better feed conversion ratio with T3 having the lowest value of 4.01 compared to the other treatments. For feed cost/dozen egg (N), Kg feed/dozen eggs, income above feed cost at N30 per egg, and income above control treatment; phytase (T3), protease (T4), roxazyme 626 (T5), and protease + roxacyme G2G (T6) diets in this study showed better performance than the control. Sorghum diet without enzyme had significantly (p<0.05) least performance for egg number. Hen housed egg production (HHP) and hen day egg production (HDP) compared to the other treatments while sorghum diet with phytase had the highest value (60.12g/day) for average egg weight compared to the other treatments. Egg quality characteristics showed the best performance for dietary treatments supplemented with phytase (T3) in all the other parameters considered, apart from the albumen height, yolk diameter, and yolk index. It was concluded therefore, that sorghum with phytase and protease supplementations can be used in layers' diets as a substitute for maize for optimum egg production.

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.

The performance of laying hens on diets using barley as the main energy source

1973 ◽  
Vol 13 (62) ◽  
pp. 251 ◽  
Author(s):  
EA Dunstan
Keyword(s):  
Energy Source ◽  
Protein Content ◽  
Crude Protein ◽  
Egg Production ◽  
Laying Hens ◽  
Metabolizable Energy ◽  
The Other ◽  
Crude Protein Content ◽  
Egg Weight ◽  
Equal Energy

An experiment compared egg production on a diet using a mixture of wheat, barley, and oats as the grain portion, with a diet in which the wheat and oats were replaced with barley. A comparison between sundried and dehydrated lucerne meal was included. A second experiment compared the same formulations of barley and mixed grain diets as used in the first experiment, and a mixed grain diet of higher crude protein content. Replacing wheat and oats with barley in an otherwise unchanged diet did not significantly affect the number of eggs produced but did increase the average egg weight by 1.1 g in both experiments, significantly so in one experiment, but not in the other. Increasing the crude protein content of the mixed grain diet did not significantly affect either egg production or egg weight. Consumption of the barley diet was greater than the mixed grain diets. This increase in consumption was less than would have been expected on the basis of equal energy intakes, indicating that the metabolizable energy value of the barley used was greater than values previously published for barley. No differences were found in performance between sundried and dehydrated lucerne meal.

Genetic parameters of the duration of fertility in hens

1992 ◽  
Vol 72 (2) ◽  
pp. 193-201 ◽  
Author(s):  
Catherine Beaumont
Keyword(s):  
Maximum Likelihood ◽  
Key Words ◽  
Genetic Parameters ◽  
Control Period ◽  
Genetic Correlations ◽  
The Other ◽  
Selection For ◽  
Heritability Estimates ◽  
Highly Correlated ◽  
Box Cox Transformation

After two successive artificial inseminations (AI) with 125 × 106 spermatozoa, various characteristics of the duration of fertility were observed in 2375 egg-type hens at 33 and 44 wk of age: number of fertile (F) or hatched (H) eggs during a 21-d control period after AI, early, medium or late embryonic mortalities occurring at the same time and efficient (De) and maximum (Dm) duration (i.e. time between AI and the first clear egg or the last fertile egg, respectively). Heritability estimates of F, H, De or Dm ranged from 0.08 to 0.31. All genetic correlations between these variables (measured at the same age) were high (0.45–0.99) as well as those between the same variable measured at different ages (0.30–0.97). Estimates of genetic parameters varied little when estimated by Henderson's method III or REML but with the second method only all estimates were within the parameter space. A Box-Cox transformation of data slightly modified heritability estimates and animal ranking after genetic evaluation. The best criterion of selection for duration of fertility seems to be H as it is economically important, well heritable and highly correlated with the other characteristics of duration of fertility. Key words: Genetic parameters, fertility, poultry, Restricted Maximum Likelihood

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