scholarly journals Nest acceptance, clutch, and oviposition traits are promising selection criteria to improve egg production in cage-free system

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0251037
Author(s):  
Lorry Becot ◽  
Nicolas Bedere ◽  
Thierry Burlot ◽  
Jenna Coton ◽  
Pascale Le Roy
Keyword(s):  
Rhode Island ◽  
Selection Criteria ◽  
Egg Production ◽  
Genetic Correlations ◽  
Breeding Systems ◽  
Likelihood Method ◽  
Free System ◽  
Genetic And Phenotypic Correlations ◽  
High Heritability ◽  
The Mean

In cage-free systems, laying hens must lay their eggs in the nests. Selecting layers based on nesting behavior would be a good strategy for improving egg production in these breeding systems. However, little is known about the genetic determinism of nest-related traits. Laying rate in the nests (LRN), clutch number (CN), oviposition traits (OT), and nest acceptance for laying (NAL) of 1,430 Rhode Island Red (RIR) hens and 1,008 White Leghorn (WL) hens were recorded in floor pens provided with individual electronic nests. Heritability and genetic and phenotypic correlations of all traits were estimated over two recording periods–the peak (24–43 weeks of age) and the middle (44–64 weeks of age) of production–by applying the restricted maximum likelihood method to an animal model. The mean oviposition time (MOT) ranged from 2 h 5 min to 3 h and from 3 h 35 min to 3 h 44 min after turning on the lights for RIR and WL hens, respectively. The mean oviposition interval ranged from 24 h 3 min to 24 h 16 min. All heritability and correlation estimates were similar for RIR and WL. Low to moderate heritability coefficients were estimated for LRN (0.04–0.25) and moderate to high heritability coefficients for CN and OT (0.27–0.68). CN and OT were negatively genetically correlated with LRN (-0.92 to -0.39) except during peak production for RIR (-0.30 to +0.43). NAL was weakly to moderately heritable (0.13–0.26). Genetic correlations between NAL and other traits were low to moderate (-0.41 to +0.44). In conclusion, CN and OT are promising selection criteria to improve egg production in cage-free systems. NAL can be also used to reduce the number of eggs laid off-nest in these breeding systems. However, variability in MOT must be maintained to limit competition for the nests.

scholarly journals EGG PRODUCTION CURVE OF RHODE ISLAND RED CHICKENS

2021 ◽  
Vol 28 (1) ◽  
pp. 78-83
Author(s):  
O. O. ONI ◽  
N. I. DIM ◽  
B. Y. ABUBAKAR ◽  
O. E. ASIRIBO
Keyword(s):  
Linear Regression ◽  
Mathematical Models ◽  
Rhode Island ◽  
Cycle Length ◽  
Egg Production ◽  
Goodness Of Fit ◽  
Production Data ◽  
Production Cycle ◽  
Breeder Hens ◽  
The Mean

Data on the monthly egg production of a strain of Rhode Island chickens (500 breeder hens) were used to test the goodness of fit of six mathematical models, viz; Exponential, Parabolic exponential, Wood's Gamma type and modified Gamma type by McNally, Inverse polynomial and Linear regression. Egg production was summarized for each hen into 28-d periods, starting from the day of firts egg. The hens were classified into different production cycle length based on the number of 28-d periods. The models were fitted to the mean results obtained for periods within groups of hens. The effect of cycle length on goodness of fit was also examined separately for the 'best' three models with highest R2 values. The egg production cycle (i.e. number of 28-d periods) varied from 9 to 15 periods. Similarly, the coefficients of determination (R2) varied from 0.16 to 0.95 from fitting the models to mean egg production data for groups of hens. The results suggest that thye 'best' three models that were chosen fitted 52 week laying records quite well, judging from their respective R2, which were higherf for McNally (0.95) and Parabolic exponential (0.93) than for wood (0.75). Based on the goodness of fit to 52-week production record, the McNally model gave the best results. However, its suitability in predicting full year production from part year record needs to be further investigated.

Genetic parameter estimates (full sib and half sib analysis) of fertility and hatchability in two strains of Rhode Island chickens

2021 ◽  
Vol 38 (1) ◽  
pp. 14-22
Author(s):  
M. Orunmuyi ◽  
I. A. Adeyinka ◽  
O.O Oni
Keyword(s):  
Rhode Island ◽  
Additive Genetic Variance ◽  
Genetic Parameter ◽  
Genetic Correlations ◽  
Reproductive Traits ◽  
Parameter Estimates ◽  
Phenotypic Correlations ◽  
Poultry Breeding ◽  
Genetic And Phenotypic Correlations ◽  
Heritability Estimates

A study was conducted to estimate the genetic parameters of fertility and hatchability in two strains of Rhode Island Red (RIR) Chickens denoted as Strain A and Strain B respectively using the full-sib (sire +dam variance) and maternal half-sib (dam variance) components. The birds were obtained from the selected populations of RIR Chickens kept at the poultry breeding programme of National Animal Production Research Institute, Shika, Zaria, Nigeria. Settable eggs were collected from mating 28 cocks to 252 hens in a ratio of 1cock:9 hens from each strain. Eggs were pedigreed according to sire and dam. Results showed that values obtained for number of egg set (EGGSET), number of fertile eggs (NFERT), number of hatched chicks (NHATCH), percentage of chicks hatched from total eggs set (PHATCH) and percentage of chicks hatched from fertile eggs (PHATCHBL) were all higher in strain A than strain B. Heritability estimates obtained from the full-sib and maternal half-sib analysis ranged from medium to high for the two strains (0.24-0.96). The maternal half sib estimates were higher (0.40-0.96) than the estimates obtained from full sibs (0.24- 0.48). Genetic and phenotypic correlations obtained for both strains were positive and similar regardless of method of estimation. Genetic correlations between EGGSET and PFERT were low in strain A using both full-sib and maternal half-sib analyses (0.09-0.14). Phenotypic correlations between EGGSET and PFERT, PHATCH and PHATCHBL were also low in both strains and regardless of method of analyses. Moderate to high heritability estimates suggest that genetic improvement can be obtained by selection of these reproductive traits. The full-sib analysis for estimating heritability will be preferred since it is assumed that only additive genetic variance contributes to the covariance between family members.

scholarly journals Potential exists to change, through breeding, the yield of individual primal carcass cuts in cattle without increasing overall carcass weight1

2019 ◽  
Vol 97 (7) ◽  
pp. 2769-2779 ◽  
Author(s):  
Michelle M Judge ◽  
Thierry Pabiou ◽  
Jessica Murphy ◽  
Stephen B Conroy ◽  
P J Hegarty ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Genetic Variability ◽  
Genetic Correlations ◽  
Carcass Weight ◽  
High Heritability ◽  
The Mean ◽  
Estimated Breeding Values ◽  
Coefficient Of Genetic Variation ◽  
Selection Of ◽  
Carcass Cuts

Abstract The ability to alter the morphology of cattle towards greater yields of higher value primal cuts has the potential to increase the value of animals at slaughter. Using weight records of 14 primal cuts from 31,827 cattle, the objective of the present study was to quantify the extent of genetic variability in these primal cuts; also of interest was the degree of genetic variability in the primal cuts adjusted to a common carcass weight. Variance components were estimated for each primal cut using animal linear mixed models. The coefficient of genetic variation in the different primal cuts ranged from 0.05 (bavette) to 0.10 (eye of round) with a mean coefficient of genetic variation of 0.07. When phenotypically adjusted to a common carcass weight, the coefficient of genetic variation of the primal cuts was lesser ranging from 0.02 to 0.07 with a mean of 0.04. The heritability of the 14 primal cuts ranged from 0.14 (bavette) to 0.75 (topside) with a mean heritability across all cuts of 0.48; the heritability estimates reduced, and ranged from 0.12 (bavette) to 0.56 (topside), when differences in carcass weight were accounted for in the statistical model. Genetic correlations between each primal cut and carcass weight were all ≥0.77; genetic correlations between each primal cut and carcass conformation score were, on average, 0.59 but when adjusted to a common carcass weight, the correlations weakened to, on average, 0.27. The genetic correlations among all 14 primal cut weights was, on average, strong (mean correlation of 0.72 with all correlations being ≥0.37); when adjusted to a common carcass weight, the mean of the genetic correlations among all primal cuts was 0.10. The ability of estimated breeding values for a selection of primal cuts to stratify animals phenotypically on the respective cut weight was demonstrated; the weight of the rump, striploin, and fillet of animals estimated to be in the top 25% genetically for the respective cut, were 10 to 24%, 12 to 24%, and 7 to 17% heavier than the weight of cuts from animals predicted to be in the worst 25% genetically for that cut. Significant exploitable genetic variability in primal carcass cuts was clearly evident even when adjusted to a common carcass weight. The high heritability of many of the primal cuts infers that large datasets are not actually required to achieve high accuracy of selection once the structure of the data and the number of progeny per sire is adequate.

scholarly journals Genetic variability for girth growth and rubber yield in Hevea brasiliensis

2006 ◽  
Vol 63 (3) ◽  
pp. 246-254 ◽  
Author(s):  
Paulo de Souza Gonçalves ◽  
Marcelo de Almeida Silva ◽  
Ligia Regina Lima Gouvêa ◽  
Erivaldo José Scaloppi Junior
Keyword(s):  
Hevea Brasiliensis ◽  
Genetic Parameters ◽  
Genetic Correlations ◽  
Basic Knowledge ◽  
Environment Interaction ◽  
Genetic Characteristics ◽  
Genotype Environment Interaction ◽  
Genetic And Phenotypic Correlations ◽  
High Heritability ◽  
Selection Intensities

Basic knowledge of genetic characteristics of populations is necessary to conduct effective breeding and selection. The objective of this paper is describing the genetic variation of rubber yield and the correlation with other traits, and estimating the genetic parameters for girth growth and total number of latex vessels. Sixty seven clones of Hevea brasiliensis (Willd. ex Adr. de Juss.) Muell.-Arg. were tested at five sites during 10 years. Characters girth growth at panel opening and rubber yield, showed broad sense heritability on plot mean level, from 0.32 to 0.66 and 0.59 to 0.92, respectively. Predicted genetic gains equal to 0.73 cm and 0.79 g increase respectively on girth and yield in the opening panel and mature phases seems realistic, even with moderate selection intensities. Genetic correlations with rubber yield, bark thickness and total number of latex vessels were very large, and almost no genotype-environment interaction was present for girth growth. High genotype-environment interaction was present for rubber yield with genetic and phenotypic correlations across the sites, ranging from 0.64 to 0.92 (genetic) and 0.63 to 0.89 (phenotypic). Total number of latex vessels rings had a high heritability, ranging from 20.0% to 64.0% in the sites E and B, respectively.

Genetic analysis of growth, production and reproduction traits afterlong-term selection in Rhode Island Red chicken

2016 ◽  
Author(s):  
Sanjeev Kumar
Keyword(s):  
Rhode Island ◽  
Egg Production ◽  
Selection Criterion ◽  
Least Square ◽  
Economic Traits ◽  
Term Selection ◽  
Body Weights ◽  
Reproduction Traits ◽  
Genetic And Phenotypic Correlations ◽  
Growth Production

In present investigation, 325 single-hatched RIR chicks that has undergone 30 generation of selection based on 40-week part-period egg production were evaluated for growth and layer economic traits using least-squares analysis of variance. Overall least-square means of body weight at 16, 20, 40 and 64 weeks of age were 1362.6±21.4g, 1791.6±24.5g, 2184.6±26.2g and 2433.8±34.2g, respectively. Males were significantly heavier than females (P£0.001) at all ages. Least-square means of age at sexual maturity, egg weight at 28, 40 and 64 weeks of age, egg number up to 40 and 64 weeks of age were 134.5±0.9days, 44.8±0.3g, 47.73±0.4g, 51.5±0.7g, 118.3±1.2eggs and 214.5±4.8eggs, respectively. Heritability estimates were high for growth and low to medium for layer economic traits. Genetic and phenotypic correlations among body weights were high and positive. The egg production up to 40 weeks revealed high and positive genetic (0.89±0.15) as well as phenotypic (0.63) correlations with egg production up to 64 weeks suggesting the its usefulness as selection criterion for genetic improvement of annual egg production.

scholarly journals Egg Production by Hens Fed with Homemade or Commercial Concentrate in a Cage-Free System

2021 ◽  
Vol 13 (12) ◽  
Author(s):  
Fernando González-Cerón ◽  
María Alejandra Padilla-Jiménez ◽  
Arturo Pro-Martínez ◽  
José Isidro Alejos de la Fuente ◽  
Leodan Tadeo Rodríguez-Ortega ◽  
...  
Keyword(s):  
Rhode Island ◽  
White Clover ◽  
Trifolium Repens ◽  
Egg Production ◽  
Egg Mass ◽  
Productive Performance ◽  
Experimental Conditions ◽  
Free System ◽  
Trifolium Repens L ◽  
System Methodology

Objective: To evaluate two types of concentrate (homemade and commercial), in laying percentage (LP, %), weight (EW, g), and egg mass (EM, g bird-1 d-1), among hens in a cage-free system. Methodology: Sixty hens aged 37 weeks (Rhode Island Red and Barred Plymouth Rock) were assigned two treatments: COM, 150 g of commercial concentrate bird-1 d-1and CAS, 150 g of homemade concentrate bird-1 d-1. The birds were managed in a cage-free system with access to a meadow of white clover (Trifolium repens L.). LP, EW and EM were evaluated for 11 weeks. Results: LP was different between treatments (P<0.05) in the last four weeks of observation. In this time, the COM birds laid 17 to 24% more than CAS birds. The EW produced by birds from the COM group (59.1 to 60.7 g) was greater (P<0.05) than that of the CAS birds (55.0 to 57.0 g). In the second half of the study period, a lower EM (P<0.05) was observed in the CAS treatment (24.7 to 31.8 g bird-1 d-1) compared to the COM treatment (39.7 to. 41.8 bird-1 d-1). Study Implications: The results obtained are only valid for the types of concentrate evaluated and under the specified experimental conditions. Conclusions: The homemade concentrate reduces the productive performance of hens in a cage-free system in terms of LP, EW, and EM, when compared to the commercial concentrate.

scholarly journals EFFECT OF FIXED FACTORS AND ESTIMATION OF GENETIC PARAMETERS OF GROWTH TRAITS FOR MOUNTAIN KIDS

2019 ◽  
Vol 50 (6) ◽  
Author(s):  
Hermiz & Baper
Keyword(s):  
Variance Components ◽  
Fixed Effects ◽  
Genetic Parameters ◽  
Maximum Likelihood Method ◽  
Growth Traits ◽  
Genetic Correlations ◽  
Likelihood Method ◽  
Phenotypic Correlations ◽  
Body Weights ◽  
Genetic And Phenotypic Correlations

Body weights at birth (469), weaning (394) and at six month of age (358) for kids utilized in this study were raised at private project in Duhok governorate, Iraq during two kidding season (2016-2017) and (2017-2018). GLM within SAS programme was used to analyze the data which include the fixed effects (age of doe, year and season of kidding, sex of kid and type of birth, regression on doe weight at kidding, and the regression of later weights of kids on earlier weights) influencing the studied traits. Restricted Maximum Likelihood Method was used to estimate repeatability, heritability, genetic and phenotypic correlations after adjusting the records for fixed effects. Variance components of random effects were tested for positive definite. Overall mean of weights at birth (BWT), weaning (WWT) and 6 month of age (WT6M) were 2.92, 15.32 and 24.45 kg, respectively. Differences among groups of age of doe in all studied traits were not significant, while year of kidding and sex of kid affect all traits significantly (p<0.01). Season of kidding affect BWT and WWT significantly (P<0.01). Single born kids were heavier (P<0.01) than twins in BWT only. Regression of BWT on doe weight at kidding (0.033 kg/kg) was significant (P<0.01), while the regressions of WWT and WT6M were not significant. The regression coefficients of WWT on BWT (1.906 kg/kg) and of WT6M on WWT (0.835 kg/kg) were highly significant (P<0.01). Repeatability estimates for BWT, WWT and WT6M were 0.47, 0.45 and 0.35, respectively; on the same order the estimates of heritability were 0.41, 0.61 and 0.79. Genetic correlations between BWT with each of WWT (0.45) and WT6M (0.55), and between WWT and WT6M (0.68) were highly significant. All phenotypic correlations between each pair of body weights were higher than genetic correlations and ranged between 0.48 and 0.73.

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.

Heritability of muscle score and genetic and phenotypic relationships with weight, fatness and eye muscle area in beef cattle

2014 ◽  
Vol 54 (9) ◽  
pp. 1443 ◽  
Author(s):  
D. L. Robinson ◽  
L. M. Cafe ◽  
W. A. McKiernan
Keyword(s):  
Major Gene ◽  
Genetic Correlations ◽  
Breeding Value ◽  
Muscle Area ◽  
Eye Muscle ◽  
Beef Carcasses ◽  
Retail Meat ◽  
Genetic And Phenotypic Correlations ◽  
High Heritability ◽  
Increasing Demand

To assess the potential for genetic improvement to help meet the increasing demand for high-yielding beef carcasses, the heritability of muscle score (MS) plus genetic and phenotypic correlations with weight and fatness traits were estimated on 1856 yearlings and 2596 weaners born from 1992 to 2012 in a predominantly Angus herd divergently selected for High/Low MS. In 2005, after noting that some cattle were positive for the 821_del11 myostatin mutation that causes muscle hypertrophy, procedures were modified to create a third group (HighHet) of High animals with one copy of this major gene. This allowed the additive genetic effects of MS to be assessed, and also the effect of the 821_del11 mutation. MS traits were found to be highly heritable (h2 = 56–63%), with an extremely high estimated genetic correlation of 99% between weaning and yearling MS. Estimated genetic correlations of MS with rib eye muscle area (EMA) in weaners and yearlings adjusted for either age or weight were 53–56%. Genetic correlations of MS with other traits were relatively low: liveweight (yearlings 5%, weaners 20%), rump fat (yearlings –7%, weaners 11%), rib fat (yearlings –17%, weaners –3%). Apart from weaning liveweight, the estimated genetic correlations were not significantly different from zero. MS had smaller estimated genetic correlations with fatness and weight traits than EMA adjusted for age. For yearlings and weaners born from 2010 to 2012, large significant differences were evident in MS of High and Low calves (4.5-point difference for yearlings; 3.4 points for weaners, on a 15-point scale) and significant differences in EMA (yearlings 2.5, weaners 1.5 cm2). In addition, the 821_del11 mutation reduced fatness, increased MS by 1.5–1.9 points and increased EMA by 2.8–3.6 cm2. With high heritability, low correlations with weight and fatness in weaners/yearlings, plus other research (Cafe et al. 2012, 2014a) showing no detrimental effect on maternal productivity or meat quality, but improvements in dressing percent, retail meat yield, meat : bone ratio and feedlot feed efficiency, the development of an estimated breeding value for MS could help improve the efficiency and profitability of beef production.

The effect of different levels of management on the assessment of differences between varieties of chickens. II. Egg production, mortality and egg weight

1964 ◽  
Vol 6 (2) ◽  
pp. 195-205 ◽  
Author(s):  
J. C. Bowman ◽  
J. C. Powell
Keyword(s):  
Egg Production ◽  
Genetic Correlations ◽  
Egg Laying ◽  
Components Of Variance ◽  
Egg Weight ◽  
The Mean ◽  
Intensive Investigation ◽  
Optimum Management ◽  
Maximum Expression ◽  
Different Levels

1. The data relating to 16 multi-location trials involving several varieties of egg-laying chickens per trial have been analysed to obtain estimates of variety × location (genotype-environment) interactions for rearing and laying mortality, hen-month and hen-housed egg production and 32-week egg weight. Significant interactions were found in about a third of the trials for all five traits though in only two cases did the interaction variance account for more than 20% of the total variance.2. Genetic correlations for varieties between locations have been calculated as 0·49 for rearing mortality, 0·50 for laying mortality, 0·72 for hen-month production, 0·76 for hen-housed production and 0·91 for egg weight. These are in close agreement with previous published estimates.3. The between-and within-variety components of variance have been calculated for each trait on each location separately. The regressions within trials and pooled values of the components on the mean level of all varieties on the location have been calculated. For hen-month production the pooled regres-son of the within-variety component on mean was negative, whilst for all other traits the pooled regressions were positive. The pooled regressions of the between-variety components on mean were all positive. It is suggested that this information indicates that comparison of varieties for single traits should be carried out on locations favourable for maximum expression of the trait. The difficulties which variety comparisons, for several traits having different optimum management regimes, would cause and the need for a more intensive investigation of the conditions conducive to genotype-environment interactions are stressed.

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