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 Relationship between Bone Quality, Egg Production and Eggshell Quality in Laying Hens at the End of an Extended Production Cycle (105 Weeks)

Animals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 623
Author(s):  
Clara Alfonso-Carrillo ◽  
Cristina Benavides-Reyes ◽  
Jon de los Mozos ◽  
Nazaret Dominguez-Gasca ◽  
Estefanía Sanchez-Rodríguez ◽  
...  
Keyword(s):  
Bone Quality ◽  
Egg Production ◽  
Breaking Strength ◽  
Bone Fractures ◽  
Quality Parameters ◽  
Production Cycle ◽  
Medullary Bone ◽  
Eggshell Quality ◽  
Ash Weight ◽  
Skeletal Integrity

(1) Background: Nowadays the industry aims to improve lay persistency for extended cycles (100 weeks or longer) to make egg production more sustainable. However, intensive egg production challenges hen health, inducing severe osteoporosis and the incidence of bone fractures. In this study, the relationship between bone quality and egg production, and/or eggshell quality, was evaluated at the end of an extended laying cycle of 100 weeks, comparing groups of hens with different production and eggshell quality parameters; (2) Methods: Quality parameters of egg (as weight, egg white height), eggshell (as thickness, weight, breaking strength, elasticity and microstructure) and tibiae bone (weight, diameter, cortical thickness, ash weight, breaking strength, medullary bone) were determined; (3) Results: Hens from groups with a high egg production and good eggshell quality have poorer bone quality (lower ash weight and lesser amount of medullary bone). However, Pearson’s correlation analysis shows no clear relationship between bone and egg/eggshell parameters. (4) Conclusions: Bone and egg production/eggshell quality are independent and can be improved separately. Medullary bone has an important contribution to bone mechanical properties, being important to accumulate enough bone medullary bone early in life to maintain skeletal integrity and eggshell quality in old hens.

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.

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.

scholarly journals Effect of Age on Bone Structure Parameters in Laying Hens

Animals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 570
Author(s):  
Masayoshi Yamada ◽  
Chongxiao Chen ◽  
Toshie Sugiyama ◽  
Woo Kyun Kim
Keyword(s):  
Cortical Bone ◽  
Bone Quality ◽  
Bone Mineral ◽  
Volume Fraction ◽  
Bone Structure ◽  
Bone Volume ◽  
Egg Laying ◽  
Medullary Bone ◽  
Mineral Density ◽  
Tibial Diaphysis

Changes in medullary and cortical bone structure with age remain unclear. Twenty Hy-Line W36 hens, 25 or 52 weeks of age, were euthanized, and both tibiae were collected when an egg was present in the magnum. Serial cross sections of the tibiae were stained with Alcian blue. The bones were scanned using micro-computed tomography. Trabecular width (Tb.Wi) was significantly higher (p < 0.05) in 25-week-old hens, whereas medullary bone tissue volume (TV) was significantly higher (p < 0.01) in 52-week-old hens. 25-week-old hens had significantly higher (p < 0.01) bone volume fraction (BVF = calcified tissue / TV). Moreover, the cortical bone parameters were significantly higher (TV and bone mineral content (BMC) at p < 0.05, and bone volume (BV) and BVF at p < 0.01) in younger hens. Open porosity and total porosity, which indicate less density, were significantly higher (p < 0.01) in older hens. Older hens showed significantly higher (p < 0.01) tibial diaphysis TV than younger hens. Younger hens had significantly higher (p < 0.01) BV, BVF and bone mineral density (BMD) of the tibial diaphysis. These findings reveal that reductions in medullary bone quality might be associated with age-related low estrogen levels and stimulation of osteoclastic bone resorption by parathyroid hormone. Cortical bone quality decreased with enlargement of the Haversian canals and loss of volume, with a longer egg-laying period leading to osteoporosis.

scholarly journals Influencia del hidrolizado de proteínas en el comportamiento bioproductivo en gallinas de la línea L1 White Leghorn

2018 ◽  
Vol 65 (2) ◽  
Author(s):  
Manuel Colas ◽  
Edmundo Oliver Pérez ◽  
Yanet Támbara
Keyword(s):  
Food Intake ◽  
Quality Indicators ◽  
Feed Intake ◽  
Egg Production ◽  
Nutritional Supplement ◽  
Protein Hydrolysates ◽  
Egg Laying ◽  
White Leghorn ◽  
Light Line ◽  
Mass Conversion

The objective of this study was to evaluate the influence of protein hydrolysates (PH), as a nutritional supplement, in the bioproduction performance of White Leghorn hens. Thirty-nine-week old light line hens were assessed during six weeks. Two treatments (T) were designed involving 320 hens each (three replications of 40 hens each). In T1, each bird received 2 ml of PH daily; the birds in T2 were not offered the product. The following variables were controlled: bioproduction (total egg production, egg-laying percentage, total feed intake, mass conversion, viability, and caused mortality); incubation indicators (eggs to plant, incubation percentage, hatchability, and top quality chicks) and; quality (feed intake by top quality chicks, and top quality chicks per hen). The hens that received the PH showed significant differences in the laying, incubation, and hatchability percentage, as well as mass conversion, and the egg to plant ratio. They showed better performance in quality indicators. It is concluded that the use of PH in light line hens improves their bioproduction performance, as well as the indicators of to incubation, egg to plant ratio, and hatchability; its use also reduces by approximately 100 grams the necessary food intake to obtain top quality chicks.

scholarly journals A production trial with layers of four hybrids under different environmental conditions in the Eastern Province of Saudi Arabia.

1971 ◽  
Vol 19 (4) ◽  
pp. 204-210
Author(s):  
H. Appelman ◽  
B.J. Bonhof
Keyword(s):  
Saudi Arabia ◽  
Rhode Island ◽  
New Hampshire ◽  
Egg Production ◽  
Live Weight ◽  
Egg Mass ◽  
White Leghorn ◽  
Eastern Province ◽  
Egg Weight ◽  
Food Consumed

161 Australorp X Rhode Island Red (RIR) X New Hampshire (NH) and 166 White Leghorn (WL) imported fowls were kept in insulated housing; 161 Australorp X RIR X NH, 166 WL, 154 RIR X WL and 148 RIR X NH X RIR fowls were kept in open houses. In the 6 groups resp., live weight at 126 days of age averaged 1602, 1227, 1578, 1234, 1397 and 1539 g, food consumption 4.02, 4.49, 4.03, 4.47, 4.25 and 4.17 kg/kg gain, overall laying percentage 56.6, 56.4, 52.5, 53.4, 55.0 and 37.5, egg production/hen 202, 201, 188, 191, 196 and 134, and egg weight 56.3, 56.3, 55.0, 55.8, 55.0 and 57.5 g. Egg mass averaged 1335, 1323, 1191, 1151, 1126 and 796 kg and food consumed/kg eggs produced 3.68, 3.53, 3.71, 3.25, 3.37 and 4.74 kg. Live weight at 16 mth of age averaged 2894, 2040, 2665, 1874, 2132 and 2517 g, and mortality 12.8, 11.1, 33.6, 43.5, 52.8 and 50.4%. (Abstract retrieved from CAB Abstracts by CABI’s permission)

scholarly journals Influence of grinding size of the main cereal of the diet on egg production and eggs quality of brown egg laying hens from 33 to 65 weeks of age

2018 ◽  
Vol 97 (7) ◽  
pp. 2506-2515 ◽  
Author(s):  
J. Herrera ◽  
B. Saldaña ◽  
L. Cámara ◽  
J.D. Berrocoso ◽  
G.G. Mateos
Keyword(s):  
Egg Production ◽  
Laying Hens ◽  
Egg Laying ◽  
Eggs Quality

STUDIES ON THE USE OF FABA BEANS IN RATIONS FOR LAYING HENS

1977 ◽  
Vol 57 (3) ◽  
pp. 421-425 ◽  
Author(s):  
A. R. ROBBLEE ◽  
D. R. CLANDININ ◽  
R. T. HARDIN ◽  
G. R. MILNE ◽  
K. DARLINGTON
Keyword(s):  
Egg Production ◽  
Egg Size ◽  
Production Efficiency ◽  
White Leghorn ◽  
Feed Conversion ◽  
Considerable Decrease ◽  
Large Size ◽  
Vicia Faba L ◽  
Faba Beans

In two experiments, White Leghorn pullets kept in batteries were fed rations containing 0, 5, 10, 15, 20 or 30% raw faba beans (Vicia faba L.) for 336 days. The rations were designed to be isocaloric, isonitrogenous and to have equal levels of methionine plus cystine. The results obtained indicated that levels up to and including 20% faba beans in ration ssupplemented with methionine had no adverse effect on mortality, rate of egg production, efficiency of feed conversion or body weight. A level of 30% faba beans resulted in increased mortality, and decreased egg production and feed conversion in one experiment but had no effect in the other. Egg size tended to decrease as the level of faba beans in the ration increased, resulting in a considerable decrease in the percentage of "large size" eggs graded according to Canadian standards. There was an increase in interior quality of the eggs as measured by Haugh units as the level of faba beans used increased. Specific gravity of the eggs was not affected by use of faba beans in the rations.

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

The nitrogen balance of laying hens

1934 ◽  
Vol 24 (4) ◽  
pp. 636-648 ◽  
Author(s):  
J. S. Willcox
Keyword(s):  
Rhode Island ◽  
Nitrogen Balance ◽  
Egg Production ◽  
Laying Hens ◽  
Egg Laying ◽  
Uniform Rate

SummaryA nitrogen balance experiment of ten weeks' duration with two Rhode Island Red laying hens is described.The observed variations in the retention of nitrogen for egg-producing purposes do not appear to be connected with the output of egg nitrogen or with the number of eggs laid in the various egg cycles.The view held by other workers that the nitrogen required for egg production can be largely if not entirely drawn from the food supplied during the laying period is confirmed.The marked storage of nitrogen which has been shown to occur immediately prior to the commencement of egg laying is not repeated during the laying period, and it is suggested that during a period of heavy egg production synthesis of the nitrogenous constituents of the egg proceeds at a fairly uniform rate.

Sign in / Sign up

Export Citation Format

Share Document