Egg Shell Quality
What is Egg Shell Quality and How to Preserve it?
Published: November 29, 2010
By: Dr. Ken W. Koelkebeck (University of Illinois)
There are many factors that affect the overall quality of the egg shell, but before discussing these factors, it is important to know what makes up the structure of the egg shell. The egg shell consists of about 94 to 97% calcium carbonate. The other three percent is organic matter and egg shell pigment. There are also as many as 8,000 microscopic pores in the shell itself. The outer coating of the shell itself consists of a mucous coating called the cuticle or bloom which is deposited on the shell just prior to lay.This protein like covering helps protect the interior contents of the egg from bacteria penetration through the shell. Egg shell quality is determined by the color, shape, and structure of the shell. Colors can range from white to tints to brown and egg shape can also vary.
Numerous factors affect the general functional quality of the egg shell. These factors affect the quality of the shell mostly prior to when the egg is laid. The thickness of an egg shell is determined by the amount of time it spends in the shell gland (uterus) and the rate of calcium deposition during egg shell formation. If the egg spends a short period of time in the shell gland, then shell thickness will be less. Also, the time of day when the egg is laid will also determine the thickness of the shell. In general, the earlier in the day or light portion of the photoperiod the thicker the shell will be. The amount or rate of calcium deposition will also affect the thickness of the shell. Some strains of birds may be able to deposit calcium for the egg shell at a faster rate than others. Another factor such as the age of the hen plays a role in determining the functional quality of the egg shell. As the hen ages, the thickness of the shell usually declines. Other egg shell quality factors such as the formation of abnormal ridges, calcium deposits, or body checks (ridges) are important considerations in determining egg shell quality.
The asthetic quality of egg shells relate to the quality factors which the consumer can see, such as soundness of the shell, cleanliness of the shell, shape of the shell, and color of the shell. Several factors do affect asthetic egg shell quality. Factors such as wash water temperature which affects the incidence of "thermal" cracks, moisture condensation on the shell, refrigeration temperature, and mechanical handling of the egg all affect the asthetic quality of the egg shell.
Microbiological contamination of the inside of the egg is greatly affected by the ability of the egg shell to stop the invasion of micro-organisms and bacteria from entering the egg through the shell's pores. When the cuticle or bloom is deposited by the hen on the shell this acts as a barrier to keep bacteria from entering the egg. When eggs are washed, however, this removes most if not all of the cuticle from the shell surface. Thus, bacteria have an easier time entering the egg after washing. Even when the cuticle is removed, the two inner shell membranes help prevent bacteria from entering the egg. These barriers provide a good line of defense against invading bacteria.
Many factors can contribute to the conservation of good egg shell quality. If the egg producer manages his flock in the proper manner by providing the proper nutrition and environmental conditions, then high egg shell quality should be achieved. A specific procedure that a producer should do to assure the production of eggs with good egg shell quality is to avoid scaring the birds so that the egg spends the normal amount of time in the shell gland. A key item to remember is to not stress the flock in any manner.
Numerous factors affect the general functional quality of the egg shell. These factors affect the quality of the shell mostly prior to when the egg is laid. The thickness of an egg shell is determined by the amount of time it spends in the shell gland (uterus) and the rate of calcium deposition during egg shell formation. If the egg spends a short period of time in the shell gland, then shell thickness will be less. Also, the time of day when the egg is laid will also determine the thickness of the shell. In general, the earlier in the day or light portion of the photoperiod the thicker the shell will be. The amount or rate of calcium deposition will also affect the thickness of the shell. Some strains of birds may be able to deposit calcium for the egg shell at a faster rate than others. Another factor such as the age of the hen plays a role in determining the functional quality of the egg shell. As the hen ages, the thickness of the shell usually declines. Other egg shell quality factors such as the formation of abnormal ridges, calcium deposits, or body checks (ridges) are important considerations in determining egg shell quality.
The asthetic quality of egg shells relate to the quality factors which the consumer can see, such as soundness of the shell, cleanliness of the shell, shape of the shell, and color of the shell. Several factors do affect asthetic egg shell quality. Factors such as wash water temperature which affects the incidence of "thermal" cracks, moisture condensation on the shell, refrigeration temperature, and mechanical handling of the egg all affect the asthetic quality of the egg shell.
Microbiological contamination of the inside of the egg is greatly affected by the ability of the egg shell to stop the invasion of micro-organisms and bacteria from entering the egg through the shell's pores. When the cuticle or bloom is deposited by the hen on the shell this acts as a barrier to keep bacteria from entering the egg. When eggs are washed, however, this removes most if not all of the cuticle from the shell surface. Thus, bacteria have an easier time entering the egg after washing. Even when the cuticle is removed, the two inner shell membranes help prevent bacteria from entering the egg. These barriers provide a good line of defense against invading bacteria.
Many factors can contribute to the conservation of good egg shell quality. If the egg producer manages his flock in the proper manner by providing the proper nutrition and environmental conditions, then high egg shell quality should be achieved. A specific procedure that a producer should do to assure the production of eggs with good egg shell quality is to avoid scaring the birds so that the egg spends the normal amount of time in the shell gland. A key item to remember is to not stress the flock in any manner.
Although it may not be practiced, the use of a "ahemeral" lighting program has shown to be effective in causing eggs to spend a longer time in the uterus, thus, producing eggs with thicker shells. Nutritionally speaking, it is important for the producer to feed a ration properly formulated with the correct amount of calcium and phosphorus in the diet (usually 3.5-3.75% calcium, .45% phosphorus). The production of eggs with thick, strong shells usually occurs from young vs. older flocks. Thus, a producer should expect more shell breakage and eggs produced with thinner shells to occur with older flocks and those producing eggs a couple of months after they've been molted. It is also important for the producer to monitor the health of the flock. Since diseases such as Infectious Bronchitis and Newcastle cause egg shell abnormalities in the texture of the shell and shape of the shell, producers should continually monitor their flock for these diseases and follow management practices to avoid their flock from contacting these diseases.
One of the egg shell quality problems that often occurs is the production of eggs having body checks. These are eggs which are cracked in the uterus during shell formation, then the egg shell forms on top of the crack. Robert Bastian reported in a newsletter published by the University of Georgia (Commercial Egg Tips) ways for producers to reduce the problem of body checks. His recommendations were to:
1) avoid overcrowding of hens in cages which produces body checked eggs because hens contact themselves and the sides of the cage,
2) use flocks that are of a relatively young age because older flocks produce more body checked eggs, and
3) use a lighting program which is no longer than the longest natural light in open houses.
There are several procedures that need to be followed in order to conserve the asthetic quality of egg shells. The frequent gathering of eggs will help prevent the accumulation of dirt and stains on the shell. In addition, when eggs are washed the temperature of the wash water should be about 20°F warmer than the eggs. This will help prevent the occurrence of thermal cracks or "blind checks" as they are sometimes called. Today's in-line commercial gathering of eggs has helped reduce the incidence of checked and cracked eggs, but producers should still be aware of problems in the collection system that could damage eggs.
As far as procedures followed to conserve micro-biological contamination of egg shells, appropriate washing and egg processing techniques should be followed. The use of the proper sanitizing agent is very important to maintaining egg shell cleanliness and free from bacteria contamination.
One of the egg shell quality problems that often occurs is the production of eggs having body checks. These are eggs which are cracked in the uterus during shell formation, then the egg shell forms on top of the crack. Robert Bastian reported in a newsletter published by the University of Georgia (Commercial Egg Tips) ways for producers to reduce the problem of body checks. His recommendations were to:
1) avoid overcrowding of hens in cages which produces body checked eggs because hens contact themselves and the sides of the cage,
2) use flocks that are of a relatively young age because older flocks produce more body checked eggs, and
3) use a lighting program which is no longer than the longest natural light in open houses.
There are several procedures that need to be followed in order to conserve the asthetic quality of egg shells. The frequent gathering of eggs will help prevent the accumulation of dirt and stains on the shell. In addition, when eggs are washed the temperature of the wash water should be about 20°F warmer than the eggs. This will help prevent the occurrence of thermal cracks or "blind checks" as they are sometimes called. Today's in-line commercial gathering of eggs has helped reduce the incidence of checked and cracked eggs, but producers should still be aware of problems in the collection system that could damage eggs.
As far as procedures followed to conserve micro-biological contamination of egg shells, appropriate washing and egg processing techniques should be followed. The use of the proper sanitizing agent is very important to maintaining egg shell cleanliness and free from bacteria contamination.
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Prinzvet Livestock Consult
25 de abril de 2011
thanks for your article. my question is what influences egg shell colour
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Tonisity
20 de abril de 2011
Dear Luc,
Thank you for your comments… please allow me to also reply.
First, please do not make me say what I did not say. You write “it is also very clear from Mr. Cortyl his comment that the major effect of butyrate is not linked to the cation (whether sodium or calcium), but from the anion (villi and mucosa integrity).” I never wrote this. I mentioned about the effect of sodium butyrate indeed, and it seems we all agree it brings important benefits at the gut level.
On the contrary, you appear to strongly believe that the cation is of outmost importance. If I understand correctly your comments, the debate should be: sodium or calcium as cation? Since you mention about “a specially coated calcium butyrate salt” I did a quick search on the internet and found that the product you describe contains 11% calcium and is recommended at 0.5 kg per MT of feed. That means the organic calcium in feed will be 55 grams per MT or 0.0055%. When a layer diet has around 3.5 to 4% calcium, I am wondering how this amount of organic calcium can make a difference?
As for the significantly wetter litter, or the higher number of dirty eggs that should be found when using sodium butyrate, I do not agree. We have good feedback from layer or broiler farms using sodium butyrate based additives, and one of their comments is that litter is drier or eggs cleaner than when they did not use the product. As you certainly know, in today’s layer farms, prevalence of dirty eggs is affected mainly by the incidence of cracked eggs (besides the availability of enough nest boxes and the frequency of egg collection), because eggs with weak shells tend to crack easily, causing newly laid eggs to be dirty. So, in my opinion, if we observe cleaner eggs it is not due to the cation itself, but rather due to the better gut health and improved nutrient absorption, leading to stronger shell, as discussed before.
I personally don’t have experience of results obtained with calcium butyrate, so I would be quite interested to get the references of the papers you mention, especially those where you observed significant less dirty eggs and dryer litter moisture when comparing calcium butyrate with sodium butyrate.
My apologies to the rest of the readers for spending a bit of time on those details, but I feel this is important.
Thank you and best regards.
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Tonisity
19 de abril de 2011
I would like to comment on the post from Mr. Abdou Gad Abdallah. You write that “as hen ages egg gets bigger with no further increase in Ca deposited on the shell resulting in thinner shell and greater number of breakages”. I would like to comment on this, as I am not sure the problem is that straight forward. For instance, Curtis et al. (2005) report that during a 1 year cycle, while percentage of albumen and yolk vary greatly with age, egg shell percentage is rather stable (from 10.3 to 9.0% of total weight).
My point is that egg size is certainly NOT THE ONLY parameter which influences shell quality. We all agree that older birds will have more shell problems. But is it really due to egg size? As reported in a trial conducted by Bennet (2004), egg weight contributed to only 5% of the increased number of thin shelled eggs between 36 and 66 weeks of age. As the hens grow older, eggs of all sizes become thin shelled. When investigating shell quality problems, it is often necessary to have a broader perspective. For example, as the author of the paper posted here mentions, “older flocks produce more body checked eggs”. Since body checked eggs have weaker shells (not thinner), that may be one of the reasons why older birds have more eggs with shell problems. Bennet also mentions that bigger eggs build up momentum as they roll out of the cage. This momentum makes them more likely to crack than smaller eggs of similar shell quality.
Egg shell quality has to be approached as a multi factorial issue. Besides health problems, management, and environmental conditions (for instance heat stress), we believe that fine-tuning of nutrition can play a role in dealing with this situation. As hens get older their digestive system is certainly less efficient. For instance, absorption of nutrients (especially minerals) is impaired as hens get older, in particular after 40-45 weeks of age. Use of sodium butyrate, which helps in development and maintenance of healthy villi, can counteract this decrease in absorption.
A solution combining sodium butyrate with other important ingredients, including vitamins and organic trace minerals such as copper or zinc, is available and has been widely tested in various parts of the world. We observe that parameters such as laying rate, FCR and mortality are improved. Also, egg quality (shell and albumen) is usually better, with higher values for the Haugh units. Our latest data indicates that when using this combination, it is possible to reduce the protein level of the diet and produce eggs at a cheaper costs while maintaining a similar quality.
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15 de marzo de 2011
Thank you for the good article about Egg Shell Quality. Today the problem for consumers is: How to recognize in the market, the good quality of eggs?
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Sanluc International nv
13 de febrero de 2011
Congratulations with the simple but comprehensive and clear overview on egg shell quality. From the nutrition side, somebody mentioned already the importance of adequate supply of some minerals (Ca, P, Trace minerals) and vitamins (D3).
More recent research and development work has documented the benificial effects of a special complex of encapsulated calciumbutyrate, on several Egg Shell Parameters (number of broken eggs, haircracks, soft eggs, dirty eggs, breaking strength) but also on inner egg quality (Haugh Units) and performance (laying rate and FCR). Contrarely to other nutritional measures, calciumbutyrate showed to impact more the elasticity of the shell that its thickness. Butyrate is known to improve gut integrity, nutrient (mineral) absorption and calcium- and energy metabolism but also reducing inflammation. The product has since been validated intensively under European and S.E. Asian conditions.
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29 de noviembre de 2010
Congratulations on the article about egg shell quality!
But, I have a question. Could you please answer this?
Could the number or the size of the pores of the egg shell be influenced by any factor? And the resistance the breaking, sufficiently related with the calcium and phosphorus ratio, what are the influences on it ?
Thanks,
Mathews
Student of Ph.D Poultry Nutrition at Federal University of Paraiba, Brazil
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18 de diciembre de 2013
I could educate myself by reading many views in this forum. Yes as a consultant in poultry i am sure how to protect the egg shell quality:
1-Genetic standards are specific and egg shell are also included in selection index for shell thickness and which contribute to breaking strength of an egg.This genetic quality has to be supported with nutrition for getting good standard shell quality of egg.
2-Management reasons which impact also a egg shell even with high genetic standards that is some virus like ND,RD interfere with calcification of the egg shell.and this also create miss shape etc.
3-Ambient temperature in tropical area also important which decide the feed consumption which is mostly 80gms to 110gm for a early laying period this need to be ensured with good standard of feed with all chemical requirements.
4-Some time nutrition and quality of toxin also impact the metabolism of required nutrients and micro nutrients and macro nutrient which also impact the shell quality.
5-Only through balance nutrition and good balance environment it is possible to derive the shell quality of egg. Egg broken on the cage,shell less egg etc are to be verified with closeness by experts.
6-sodium % and chlorine % in feed need to be around 0.18% each and calcium for new layer can be some where 3.6-3.8%, available ph need to be around 0.3% etc. But over all good balance ration and aflatoxin free or any other toxin feed need to be assured.
Let us read more in net we get many options and mechanisms which are very helpful for both color and white egg layers and breeders.
thank you sir
dr m rath
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18 de diciembre de 2013
Weak Shell Egg is due to deficiency of Vitamin D3, Calcium and Phosphorus. Supplementing these three through feed will be effective in bringing the birds boost their egg shell quality
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8 de mayo de 2011
One question for the author: If we feed high level of fat-soluble vitamins in order to improve color of the egg shell, which should be the right dosage? and how long will see a significant improvement?thank you.
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25 de abril de 2011
The laying hen nutrition is not every where in the world an exact science.
We have a lot of various parameters, strains, raw matrials, production management etc…etc…etc…
For these reasons we need not to forget the basics…
Nutrition, means…Digestion, means …Absorption.
For long time, nutritionnists have forgotten an essential organ : the Pancreas.
Today, with the sodium butyrate we have the exceptional opportunity not to only think the action of stomach or intestine but also…pancreas.
Nutrition needs to be more & more functional… to help by itself.
Yes, sodium butyrate is before all a functional product.
Functional to the attraction to eat (feed intake)
Functional to the germs control (less germs in feces)
Functional to the size of villi ( over 30% length)
Functional to the pancréas sécrétion juice (execrine & endocrine)
Functional to the immunity (intestine is the first disponible energy)
All of these are very good, but there is a constraint
Sodium butyrate needs to be dissociated in the intestine, and not before
Sodium butyrate needs to be strongly present in the intestine & not with homeopathic dosage… the more you use …2kg, 3kg, 4kg… the more it works.
Sodium butyrate seems be the true antibiotic substitute.
I never said (Luc) that Calcium butyrate was a bad product .
I only said that sodium salt have a the largest bibliography (X100 than calcium)
I only said that calcium salt is superfluous in laying hens… there still is a lot of calcium..
I only said that calcium salt is not advised for young animal (risk of calcium soap)
At last and not at least… I* said than Calcium butyrate is without osmotic effect, because the osmotic effect is strictly sodic … * ( the physiology said that…not me)
And when you know the high level and need of osmotic effects for the absorption mecanism… you can may be have some doubts about the calcium salt interest ?
But calcium salt can be still active for… the others parameters..
Anyway…
It is true (Luc) in 1995, I perfected and sold the first sodium butyrate for animal nutrition in the world. .. and like a… pater bonum…I continued to perfect it
Our expérience is laying hens and sodium butyrate
The problem is that we quickly stopped to promote the cracked, broked, dirty eggs advantage of sodium butyrate , because we had observed as well as a strong effects on the ESG (egg specific gravity/ Prof Harms method) on the number of eggs, on the weight of eggs, on the decrease of salmonellas in the fèces, on the level of mortality, and on the length of laying…
You can understand that the only effect on the shell quality was into the background…
Why so nice result :
1 / because our new sodium butyrate product (patented) double buffer… with a longer dissociation in the time
2/ because the laying hens have long life, and with the diet rich in calcium there is like
a kératinisation playing as a filter on the absorption and assimilation.
3/ because our product is able through the progressive intestinal dissociation to suppress the kératinisation ( around 40 weeks)of the villi and even to relaunch the size of the villi..
4/ and because It will be possible to see on the laying courbs an increase of all the parameters…
That’s why our new sodium butyrate double buffer is able to help the laying production by a strong functional stimulation effect.
Philippe Gossart
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