Estimates of genetic parameters relevant in selection for certain aspects of egg quality

1964 ◽  
Vol 15 (4) ◽  
pp. 719 ◽  
Author(s):  
JA Morris
Keyword(s):  
Shell Thickness ◽  
Egg Production ◽  
Genetic Parameters ◽  
Egg Quality ◽  
Genetic Correlations ◽  
Direct Selection ◽  
Early Measurement ◽  
Shell Quality ◽  
Selection For

Thick albumen quality of eggs laid by pullets at the approximate ages of 34 and 64 weeks was measured both for fresh eggs and for eggs stored under reasonably uniform conditions for a period of 14 days. Subsequent analyses provided estimates of heritability of these various traits as well as genetic correlations between them. Heritability was high in all cases except for the 64-weeks measurements on stored eggs. Theoretically, selection based on 34-weeks measurements of albumen quality of fresh eggs should be equally as effective, per generation, as direct selection in improving 64weeks fresh quality. Furthermore, this indirect selection is more effective than direct selection in improving the quality of stored eggs, at both 34 and 64 weeks of age. The heritability of egg specific gravity (used as an indicator of shell thickness) is of intermediate to high value for estimates made both early and late in the pullet year. The genetic correlation between the early and late measurements is high, and selection based on the early measurement should be almost as effective (when assessed per generation) as on the late measurement in causing genetic improvement in late shell quality. All quality traits examined showed positive genetic relationship with each other, although many of the correlations are of low value. The only serious genetic antagonism disclosed was between each of the two assessments of shell thickness and total egg production. There was no evidence of genetic antagonism between albumen quality and total egg production.

Genetic parameters for egg weight v. age curve, and other egg production and egg weight traits, in synthetic lines of chickens

1983 ◽  
Vol 34 (1) ◽  
pp. 85 ◽  
Author(s):  
BH Yoo ◽  
BL Sheldon ◽  
RN Podger
Keyword(s):  
Standard Deviation ◽  
Genetic Correlation ◽  
Egg Production ◽  
Genetic Parameters ◽  
Genetic Correlations ◽  
Egg Mass ◽  
Control Line ◽  
Egg Weight ◽  
Egg Number ◽  
Selection For

An exponential curve, W = P-Qexp(- Rt), where W is egg weight at age t, was fitted to egg weights of individual pullets, and genetic parameters were estimated for P, Q and R, the residual standard deviation and other egg weight and egg production characters. The data consisted of records collected over six generations on more than 4000 pullets in two selection lines and a control line which originated from a synthetic gene pool of White Leghorn x Australorp crosses. The half-sib and offspring-on-parent regression estimates of heritability pooled over the lines were 0.23 and 0.33 for P, 0.14 and 0.20 for Q, and 0.14 and 0.25 for R. Genetic correlations were estimated to be -0.10 between P and Q, -0.46 between P and R, and 0.90 between Q and R. These estimates suggest that the egg weight v. age curve may be modified to increase the proportion of eggs in desirable weight grades and reduce the incidence of oversized eggs later in the production year. The genetic correlation between mean weight of first 10 eggs and egg weight at 62 weeks of age was estimated to be 0.68, further suggesting that early egg weight may be improved partly independently of late egg weight. The heritability estimates of egg mass output were not higher than those of egg number in spite of the highly heritable average egg weight being an important component of egg mass, probably because of the negative genetic correlation (r = -0.49) between egg number and average egg weight. The standard deviation of individual pullet's egg weights was moderately heritable and genetically correlated positively with egg weight characters and negatively with egg production; these estimates were consistent with the responses to selection for reduced egg weight variability observed elsewhere

scholarly journals The effect of dietary phytase and various available phosphorus levels on performance and egg quality in Japanese quail

2019 ◽  
Vol 20 ◽  
Author(s):  
Rafaella Rossetto ◽  
Maurício Barreta ◽  
Marcos José Migliorini ◽  
Fabíula Pecher ◽  
Lenílson Fonseca Roza ◽  
...  
Keyword(s):  
Egg Production ◽  
Egg Quality ◽  
Quality Parameters ◽  
Available Phosphorus ◽  
Feed Conversion ◽  
Shell Quality ◽  
Randomized Experimental Design ◽  
Phytic Phosphorus ◽  
Phosphorus Levels

SUMMARY Birds show poor utilization of phytic phosphorus in their diets because of the lack of endogenous enzymes to digest phosphorus and make it bioavailable. Therefore, the objective of this study was to evaluate phytase supplementation in the diets of laying quails. Eighty quails were used in a completely randomized experimental design with five treatments and four replicates of four birds each. The treatments were as follows: 0.35% Pd; 0.20% Pd; 0.20% Pd + 500FTUs of phytase; 0.09% Pd; 0.09% Pd + 500 FTUs of phytase. The birds were housed in metallic batteries during a trial period of 21 days, for evaluation of egg production, egg weight, feed intake and feed conversion. After being collected, the eggs were sent to the nutrition laboratory of the department of zootechnics of the CEO/Udesc, where analyses of albumin, yolk and shell quality were performed. The results were subjected to analysis of variance, and the differences between the averages were compared using the Tukey test at 5% of significance. No differences (P> 0.05) were observed in terms of performance and egg quality parameters. We conclude that the inclusion of phytase in the diet of laying quails can be accomplished without compromising the performance and quality of the eggs. Additionally, 0.09% of 22 disponible phosphorus can be used to grant adequate performance for 21 days.

scholarly journals Available phosphorus in poultry. 1. Effect of phosphorus levels on the performance of laying hens and their egg quality, hatchability, bone analysis and strength in relation to calcium and phosphorus in blood plasma.

1979 ◽  
Vol 27 (2) ◽  
pp. 176-183
Author(s):  
A.R. El Boushy
Keyword(s):  
Shell Thickness ◽  
Egg Production ◽  
Laying Hens ◽  
Egg Quality ◽  
Breaking Strength ◽  
Available Phosphorus ◽  
Inorganic P ◽  
Shell Quality ◽  
Calcium And Phosphorus ◽  
Phosphorus Levels

1. For 6 months 432 medium heavy laying hens were given diets which supplied 0.16, 0.20, 0.40, 0.60, 0.80 or 1.00% available phosphorus. Egg production was greatest by hens given 0.20 or 0.40% P and least by those given 0.16%. Feed intake did not differ among groups. Heaviest eggs, 62.2 g, were laid by hens given 1.00% P. Shell quality, determined from shell percentage, shell thickness and shell index, decreased as P in the diet increased. Hatchability, yolk and white indices of eggs and calcium, P and ash in tibiae of chicks one day old did not differ among groups. Ca in blood of hens did not differ among groups but inorganic P in plasma increased with increasing P in the diet. Ash, Ca and P in tibiae and breaking strength of tibiae of hens increased with increasing P in the diet. (Abstract retrieved from CAB Abstracts by CABI’s permission)

scholarly journals No evidence that selection for egg production persistency causes loss of bone quality in laying hens

2021 ◽  
Vol 53 (1) ◽  
Author(s):  
Ian C. Dunn ◽  
Dirk-Jan De Koning ◽  
Heather A. McCormack ◽  
Robert H. Fleming ◽  
Peter W. Wilson ◽  
...  
Keyword(s):  
Rhode Island ◽  
Bone Quality ◽  
Egg Production ◽  
Breaking Strength ◽  
Genetic Correlations ◽  
Egg Laying ◽  
White Leghorn ◽  
Medullary Bone ◽  
Selection For

Abstract Background The physiological adaptations that have evolved for egg laying make hens susceptible to bone fractures and keel bone damage. In modern laying hen breeds, longer periods of egg laying could result in a greater risk of poor bone quality, and selection for increased egg production has frequently been stated to be a cause. However, the existing literature does not support this hypothesis. To test the hypothesis that egg production is associated with quality, breaking strength and density of bone, genetic correlations between these traits were estimated in White Leghorn and Rhode Island Red breeds. Genetic correlations of cortical and medullary bone material chemical properties with bone quality were also estimated, in order to identify methods to improve bone quality with appropriately targeted measurement of key traits. Results Estimates of heritability for bone quality traits were moderate (0.19–0.59) for both White Leghorn and Rhode Island Red breeds, except for the keel bone trait, which had a heritability estimate equal to zero. There was no evidence for genetic or phenotypic relationships between post-peak egg production and bone quality. In the White Leghorn breed, the estimate of the genetic correlation between pre-peak production/age at first egg and bone quality was significant and negative (− 0.7 to − 0.4). Estimates of heritability of thermogravimetric measurements of tibial medullary bone mineralisation were significant (0.18–0.41), as were estimates of their genetic correlations with tibia breaking strength and density (0.6–0.9). Conclusions The low genetic correlation of post-peak egg production with bone quality suggests that selection for increased persistency of egg production may not adversely affect bone quality. Onset of puberty and mineralisation of the medullary bone, which is a specialised adaptation for egg laying, were identified as important factors associated with the quality of the skeleton later during egg production. These are traits for which genetic, as well as environmental and management factors can positively impact the overall quality of the skeleton of laying hens.

scholarly journals Genetic parameters by Bayesian inference for dual purpose Jaffarabadi buffaloes

2012 ◽  
Vol 55 (6) ◽  
pp. 567-576 ◽  
Author(s):  
C. H. Mendes Malhado ◽  
A. C. Mendes Malhado ◽  
A. Amorim Ramos ◽  
P. L. Souza Carneiro ◽  
F. Siewerdt ◽  
...  
Keyword(s):  
Bayesian Inference ◽  
Milk Yield ◽  
Genetic Parameters ◽  
Growth Traits ◽  
Average Daily Gain ◽  
Genetic Correlations ◽  
Direct Selection ◽  
Dual Purpose ◽  
Lactation Length ◽  
Selection For

Abstract. Knowledge of genetic parameters is essential for improved reproductive management and increased yield. Quantitative analysis of genetic parameters is lacking for many breeds of buffaloes. This article provides the first estimate of genetic parameters for dual purpose (meat and milk) Brazilian Jaffarabadi buffaloes, using Bayesian inference. Data on milk yield (MY), lactation length (LL), weight at 205 days (W205) and 365 (W365) days of age, and average daily gain (ADG) from 205 to 365 days of age were collected in two herds. Bivariate analyses (using the program MTGSAM) were performed with the Gibbs sampler to obtain estimates of variance and covariance. Average lactation milk yield and lactation length were 1620.2±450.9 kg and 257.6±46.8 days, respectively, and the mean values for weight traits (kg) were 181.6±63.3 (W205), 298.04±116.1 (W365), and 0.73±0.35 (ADG). Heritability estimates (modes) were 0.16 for MY, 0.10 for LL, 0.43 for W205, 0.48 for W365 and 0.32 for ADG. There was a high genetic correlation (0.96) between milk yield and lactation length and very high genetic correlations (0.99) between the three growth traits. Our data suggest that both milk production and growth traits have clear potential for yield improvement through direct selection in this dual purpose breed. The selection for weight at an early age would be successful and selection for MY can be performed in the first lactation.

scholarly journals Influence of selection for egg production on egg quality traits in Japanese quail

2021 ◽  
Vol 51 (1) ◽  
Author(s):  
Mahmoud M. El-Attrouny ◽  
Mahmoud M. Iraqi
Keyword(s):  
Japanese Quail ◽  
Egg Production ◽  
Egg Quality ◽  
Genetic Correlations ◽  
Selection Response ◽  
Egg Laying ◽  
Internal Quality ◽  
Correlated Response ◽  
Quality Traits ◽  
Selection For

The current study investigated the influence of selection for increased egg production on external and internal egg quality traits over five generations in Japanese quail. A total of 4325 fresh eggs from 1326 females were collected each week during the egg-laying period to estimate heritability, genetic and phenotypic correlations, and correlated response of external and internal egg quality traits to selection for egg number (EN). The direct response to selection indicated an increase of 7.7 ± 0.27 eggs produced during the 90 days following production of the first egg. The correlated responses to selection indicated that selection for higher EN can be expected to increase EW and increase egg quality. Estimates of heritability ranged from 0. 11 to 0.35 for external egg quality traits and from 0.08 to 0.32 for internal egg quality traits. Estimates of the genetic correlations of EN with external and internal traits were positive, ranging from 0.09 to 0.25 and from 0.02 to 0.27, respectively. These estimates indicated few if any genetic antagonisms that would adversely affect selection response. However, eggshell thickness would not be expected to change as a result of selection for EN. Thus, the external and internal quality of Japanese quail eggs could be improved by selection for high egg production.

scholarly journals Analysis of changes in egg quality of broiler breeders during the first reproduction period

2012 ◽  
Vol 12 (4) ◽  
pp. 609-620 ◽  
Author(s):  
Helena Kontecka ◽  
Sebastian Nowaczewski ◽  
Marta M. Sierszuła
Keyword(s):  
Shell Thickness ◽  
Egg Quality ◽  
Negative Relationship ◽  
Reproductive Season ◽  
Egg Mass ◽  
Broiler Breeders ◽  
Egg Weight ◽  
Shell Quality ◽  
Morphological Composition

AbstractIn reproductive flocks of poultry it is very important to obtain a large number of eggs with normal structure, optimal morphological composition and interior quality. These elements have very significant influence on the biological value of the egg, which determines normal development of the embryo. The aim of the study was to analyse the physical characteristics, morphological composition and quality of individual components of the eggs of Cobb 500 broiler breeders during the first year of reproduction. The research material was hatching eggs (280 pcs), whose quality was assessed 7 times in the reproductive season at 5-week intervals. The eggs were examined when the hens were aged 26, 31, 36, 41, 46, 51 and 56 weeks (40 eggs for each age). The following characteristics were evaluated: egg weight (g); egg shape index (%); egg specific gravity (g/cm3); shell thickness (mm); average number of pores in the eggshell (pcs/0.25 cm2); yolk, white and shell weight (g) and their percentage in the egg mass; yolk index (%) and the number of Haugh units. The investigations proved that as the reproductive season of hens progressed, the weight of their eggs increased. Above all, this was due to the increase in the yolk weight, because its percentage in the egg weight rose with bird age, whereas the percentage of the white decreased. However, as the reproductive season progressed the quality of both the yolk and white deteriorated. No negative relationship between the age of hens and shell quality (weight, thickness) was observed. Only when the birds were aged 56 weeks, the shell thickness was found to be significantly smaller.

scholarly journals Genetic parameters and efficiency of early selection for half rotation-aged growth and form traits in Pinus taeda in China

2013 ◽  
Vol 62 (1-6) ◽  
pp. 277-284 ◽  
Author(s):  
Huixiao Yang ◽  
Tianyi Liu ◽  
Chunxin Liu ◽  
Jinbang Wang ◽  
Kaer Chen ◽  
...  
Keyword(s):  
Pinus Taeda ◽  
Genetic Parameters ◽  
Growth Traits ◽  
Genetic Correlations ◽  
Early Selection ◽  
Direct Selection ◽  
Individual Tree ◽  
Stem Straightness ◽  
Selection For ◽  
Heritability Estimates

Abstract Genetic parameters for height (H), diameter at breast height (DBH), stem straightness (STR), and under crown clear bole height (CH) of loblolly pine (Pinus taeda L.) were estimated for 255 families (209 open pollinated (OP) and 46 controlled pollinated (CP) families) using a family model and an individual tree model at age 1, 2, 3, 5, 11, and 15 years. Heritability estimates for growth traits of individual trees at age 11 years were the highest (0.17-0.78), and those at age 15 years were the lowest (0.05-0.74). Heritability estimates for DBH, STR, and CH were lower than those for H. Genetic correlations between H and DBH were generally strongly positive, attained a maximum values at age 2 to 3, and declined slightly thereafter. The genetic correlations between CH at age 11 and both H and DBH at different ages were moderate. Age-age genetic correlations for growth traits were moderate to high (0.56-0.91) at age 5 for half-rotation age (15 years), indicating the opportunity exists for early selection. Indirect selection from the age 5 to 11 years for H and DBH could be expected to produce gains of over 50% and 35% respectively, for these two ages, relative to direct selection at age 15. Efficiencies of early selection for H and DBH indicated that growth at maturity could be improved by early selection.

scholarly journals Egg production and quality of Magelang duck, Mojosari duck, and their reciprocal crosses

2020 ◽  
Vol 30 (3) ◽  
pp. 180-183
Author(s):  
Henrik Henrik ◽  
Marhayani Marhayani
Keyword(s):  
Analysis Of Variance ◽  
Shell Thickness ◽  
Egg Production ◽  
Egg Quality ◽  
Egg Weight ◽  
Reciprocal Crosses ◽  
Randomized Design ◽  
Variable Data ◽  
Haugh Unit

This experiment was conducted to study the egg production and quality of Magelang, Mojosari duck, and their reciprocal crosses. Forty-eight of twenty weeks old ducks were used for a total of 4 treatments. The treatments were T1=Magelang duck; T2= ♂ Magelang x ♀ Mojosari; T3=Mojosari; and T4= ♂ Mojosari x ♀ Magelang. This research was design by Completed Randomized Design and replicated by 10 times according to number of female ducks in every treatment. Hen Day Production (HDP) as long as 12 weeks were collected as an egg production variable. Egg weight, albumen weight, yolk weight, shell thickness, and Haugh Unit (HU) as the egg quality variable. Data were analyzed by Analysis of Variance with one-way classification and Honestly Significance Difference. The result showed that were significantly different (P<0.01) on egg production and quality. The egg production was 60.57, 65.29, 68.86, and 61.00%, egg weight was 67.14, 59.79, 61.80, and 6.40 g, yolk weight was 25.06, 23.34, 23.23, and 24.46 g, albumen weight was 33.44, 31.41, 31.73, and 33.35 g, shell thickness were 0.50, 0.60, 0.57, and 0.53, HU were 74.24, 74.48, 72.57, and 71.03 respectively for T1, T2, T3, and T4. Egg production of Mojosari duck higher than Magelang duck (P<0.01) whereas egg quality of Magelang duck higher than Mojosari duck (P<0.01).

Japon Bıldırcını Rasyonlarında Soya Küspesi Yerine Pamuk Tohumu Küspesi İkamesinin Yumurta Verim ve Kalite Özelliklerine Etkisi

2013 ◽  
Vol 1 (1) ◽  
pp. 44 ◽  
Author(s):  
Arda Yıldırım ◽  
Ergin Öztürk
Keyword(s):  
Protein Content ◽  
Cottonseed Meal ◽  
Soybean Meal ◽  
Shell Thickness ◽  
Egg Production ◽  
Egg Quality ◽  
Yield Traits

This study was conducted to determine the effect of cottonseed meal (CSM) incorporated into laying rations in place of soybean meal (SBM) at different ratios on yield traits. The birds began to lay at 6th week, 180 female and 45 male quails were used in laying period experiment. Birds were fed with rations containing 20% CP and 3000 Kcal/kg ME up to 20-week age (Laying period). CSM as a substitute, five different rations of the protein content (0, 30, 58, 86 and 100%) for SBM to basal diets based on corn-soybean meal were used. The results showed that there were no differences in terms of egg yield traits, cumulative feed consumptions and viabilities during the laying period. The highest dry shell rate and shell thickness were obtained from 5th group and 1st group, respectively. As a result, adding CSM instead of SBM in laying period were no significantly differences in terms of egg production and egg quality in laying period.

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