Vitamin D Severe Deficiency in Layi ...

Vitamin D Severe Deficiency in Laying Hens

Vitamin D Severe Deficiency in Laying Hens

In confined laying hens, signs of deficiency begin to occur as soon as 2 weeks after they are deprived of vitamin D. The first sign is a marked increase in the number of thin-shelled eggs and soft-shelled eggs, followed soon after by a significant decrease in egg production.  (1, 2)

Individual hens may show temporary loss of the use of the legs with recovery after laying an egg that usually is shell-less. During periods of extreme leg weakness, hens show a characteristic posture that has been described as a "penguin-type-squat". Later, beak, claws, and keel become very soft and pliable. Vitamin D metabolism has been implicated in problems of eggshell quality.
(1, 2)

 Observed Clinical Signs Happenings

Egg Drop

  • Egg production declines rapidly
  • Several cycles of decreased egg production and shell strength may each be followed by periods of relatively normal production and shell strength

Visibly sick birds

  • Hens may show temporary loss of the use of the legs, with recovery after laying  an egg that is usually shell-less
  • During periods of extreme leg weakness, hens show a characteristic posture that had been described  as a “penguin-type squat”Egg quality

Egg quality

  • A marked increase in the number of thin-shelled  and soft-shelled eggs
  • Shell-less
  • Eggshell strength decreased
  • Thin-shelled and soft-shelled or porous eggs
  • Shell-less Soft Shell
  • Egg specific gravity score lower (should be above 1.080 (1.068 thinnest shells)

Lameness or unusual movement incoordination ataxia

  • Temporary loss of the use of legs
  • Extreme leg weakness

Head Comb Wattles Face Nostrils Sinuses Mount Beak Earlobes

  • Beak, claws, become very soft and pliable

Body Parts (Neck wings breast abdomen shanks legs hocks feet joints vent skin)

  • The sternum usually bend, and the ribs lose their normal rigidity
  • keel become very soft and pliable

Diet or Feed Changes (Recent Feed delivery, Recent formulation /diet, Other silo or improper storage, another feed brand)

  • Recent formulation /diet

Vitamin D Severe Deficiency in Laying Hens DOES NOT exhibit or manifest any of the following clinical signs happenings:

  • Egg production drops gradually
  • Mortality above the standard
  • Many visibly sick birds
  • Flock behaviour activity change
  • Droppings abnormalities
  • Respiratory abnormalities
  • Neurological Nervous
  • Eyes abnormalities
  • Feathers abnormalities
  • Feed Consumption Changes
  • Internal Egg defects
Causing Agents
Inadequate dietary vitamin D3
Affected Systems/Organs
Reproductive and Locomotion System
Spread
N/A
Mainly Affects
Egg Production and Egg Quality
Solution
Adequate levels of vitamin D3. Calcium and Phosphorous ratio in the diet.
Suggested Actions
  • Can be confirmed with clinical signs and gross lesions
  • Technical assistance recommended
  • Can be managed with feed additives, off-the-shelf medications
  • Diagnosis should be confirmed with rapid assays and/or a certified laboratory
  • Veterinary intervention is recommended

Impact on Egg quality

3

Impact on Liveability

0


Impact on Production

3

Overall Economic Impact

3



  1. Y.M. Saif. 2008. Disease of Poultry. 12th Edition. page 1126
  2. David E. Swayne. 2013.  Diseases of Poultry 13th Edition. page 1211
  3. Mark Pattison, Paul F. McMullin, Janet M. Bradbury. Dennis J. Alexander. 2008. Poultry Diseases. 6th Edition.
  4. Paul McMullin. 2004. A Pocket Guide to Poultry Health and Disease. First Edition.
  5. Steven Leeson, John D. Summers. 2008. Commercial Poultry Nutrition. Third Edition.
  6. Donald D. Bell, Williams D. Weaver. 2009.  Commercial Chicken Meat and Egg Production. Fifth Edition.
  7. Gail Damerow 1994. The Chicken Health Handbook.

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