EGG QUALITY · How to identify eggshell quality defects and the causes. · How to identify internal quality defects and the causes.
EGGSHELL QUALITY Problem
Causes
Cracked/broken eggs: large cracks and holes % in production: increases with the age of the hen. 1–5 % of total production
Old birds (> 50–60 weeks) Mineral deficiencies or imbalance Saline water Diseases with ovary tropism High temperatures Mechanical damage during collection
Hairline cracks: very fine cracks that require efficient candling % in production: varies with the age and the % of cracked of broken eggs
Old birds (> 50–60 weeks) Mineral deficiencies or imbalance Saline water Diseases with ovary tropism High temperatures Mechanical damage during collection Infrequent egg collection
Star cracks: fine cracks radiating outwards from a central point of impact % in production: varies with the age, 1–2 % of the total production
Old birds (> 50–60 weeks) Mineral deficiencies or imbalance Saline water Diseases with ovary tropism High temperatures Mechanical damage during collection Infrequent egg collection
Shell-less eggs and thin shelled: no shell or very thin shell, very easy to break % in production: varies 0.5–6 %. High levels possible with pullets in early maturity
Immature shell gland Disrupted deposition of calcium in shell Mineral deficiencies or imbalance Saline water Diseases with ovary tropism Mechanical damage during collection Infrequent egg collection
Sandpaper or rough shell: eggs with rough texture areas unevenly distributed over the shell % in production: the incidence should be < 1 %
Diseases with ovary tropism and avian encephalomyelitis Disrupted egg oviposition or egg retention Sudden increase of light during lay Water shortage
Misshapen eggs: shell marred by flat sides or body checks (ribs or grooves) % in production: can rise to 2 % at start of lay and later almost disappear unless there is an issue
Immature shell gland Diseases with ovary tropism Stress caused by frights and disruption Crowding
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EGG QUALITY EGGSHELL QUALITY Problem
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Causes
Flat sided eggs: part of the shell is flattened % in production: < 1 %
Diseases with ovary tropism and avian encephalomyelitis Disrupted egg deposition Sudden increase of light during lay Crowding
Pimples: small lumps of calcified material on the eggshell % in production: around 1 % is common
Old birds Excess of Ca Sudden increase of light during lay Crowding
Pinholes: small holes in the eggshell % in production: < 0.5%
Old birds Mineral deficiencies or imbalance Damage caused by hen or sharp objects in cages or collection conveyor
Mottled or glassy shell: appears mottled at candling % in production: not usually undegraded unless the condition is obvious. Incidence varies
High humidity in the layer house Mineral deficiencies Crowding Diseases with ovary tropism and infection bursal disease in parent stocks
EGG QUALITY ALBUMEN QUALITY Causes
Physiological
Age of bird
Management
High temperature of storage. Heat stress
Diseases
Bronchitis, Newcastle
Nutrition
Low CP or Lys diets Low level of vitamin E or C during heat stress Low levels of trace minerals
Haugh units
Temperature
Description
Days in storage
Contamination Vanadium
YOLK QUALITY Problem
Causes
Blood spots: blood spots on the surface of the yolk % in production: incidence varies, 1–2 %
Deficiencies in vitamin A and K Fungal toxins Continuous light programs or intermittent light periods Fright and disruption Avian encephalomyelitis
Meat spots: brown colored, pieces of tissue of the ovary or partially broken-down blood spots % in production: 1–3 %
Deficiencies in vitamin A and K Fungal toxins Continuous light programs or intermittent light periods Fright and disruption Avian encephalomyelitis
Pale yolks: the egg yolk doesn’t have the expected color % in production: incidence varies based on the issue
Gut health issues Mycotoxines Liver damage Oxidation of the added pigments Wrong mixing of the pigments
KEY POINTS · Internal and external egg quality is a powerful tool to address production issues. · A certain percentage of defects is considered normal. · Correct egg management is the best way to improve internal and external egg quality.
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