Avian Tuberculosis (TB) in Laying H ...

Avian Tuberculosis (TB) in Laying Hens

Avian Tuberculosis (TB) in Laying Hens

Observed Clinical Signs Happenings

Visibly sick birds

  • Few visibly sick birds
  • Comb, wattle and earlobes often appear pale and thinner than normal and have dry epidermis
  • The face of affected birds appears smaller than normal
  • Birds will be less lively than its pen mates
  • Birds will fatigue easily
  • Birds may be depressed
  • Birds will fatigue easily
  • Some may adopt a sitting position
  • Progressive and striking loss of weight commonly occurs
  • Atrophy of breast muscles with the prominent keel
  • One group within the flock had good body condition continued to lay eggs. Another group within the same flock was emaciated, did no lay eggs.

Mortality

  • Low mortality or increases gradually
  • Affected birds may die within a few months  or live for many depending on the severity or extent  of the disease
  • Sporadic deaths

Dead Birds

  • Poor body fleshing condition
  • Occasionally, birds may die suddenly in good bodily condition

Dropping

  • Often there is persistent diarrhea with soiling of the tail feathers
  • Intestinal nodules may be ulcerative, resulting in severe diarrhea
  • Diarrhea with soiling of the tail feathers
  • Soiled vent feathers or pasty droppings
  • Feces smeared on feathers around the vent

Head Comb Wattles Face Nostrils Sinuses Mount Beak Earlobes

  • Comb, wattle and earlobes often appear pale and thinner than normal and have dry epidermis
  • Occasionally, the comb and wattles have a bluish discolouration
  •  Icterus of the comb and wattles is an indicator of advanced hepatic damage may be noted
  • One group within the flock had good body condition continued to lay eggs. Another group within the same flock was emaciated, did no lay eggs.

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

  • Atrophy of breast muscles with a prominent keel
  • Progressive and striking loss of weight commonly occurs
  • Atrophy of breast muscles with the prominent keel
  • Loss weight commonly occurs

Lameness or unusual movement, incoordination, ataxia

  • In many instances, the birds reveal and unilateral lameness
  • The birds walk with a peculiar jerky hopping gait
  • Paralysis from tuberculous arthritis can sometimes occur

Feather Abnormalities

  • Feathers assume a dull and ruffled appearance
  • Diarrhea with soiling of the tail feathers
  • Soiled vent feathers or pasty droppings
  • Feces smeared on feathers around the vent
  • Dirty or Pasty vents or feathers with droppings around the vent

Avian Tuberculosis (TB) in Laying Hens, show, exhibit, or manifest any of the following clinical signs happenings:

Observed Clinical Signs Happenings

ALWAYS

NEVER

SOMETIMES

Egg drop

 

  •  

 

Mortality above the standard

  •  

 

 

Low mortality or increases gradually

  •  

 

 

High mortality or increases rapidly

 

  •  

 

Dead birds

  •  

 

 

Dead birds in Good bodily condition

 

 

  •  

Dead birds in Poor bodily  condition

  •  

 

 

Visibly sick birds

  •  

 

 

Few visibly sick birds

  •  

 

 

Many visibly sick birds

 

  •  

 

Flock behaviour activity change

 

  •  

 

Droppings abnormalities

  •  

 

 

Respiratory abnormalities

 

  •  

 

Neurological Nervous

 

  •  

 

Lameness or unusual movements, incoordination, reluctance to move

 

 

  •  

Eyes abnormalities

 

  •  

 

Head: Comb Wattles Face Nostrils Sinuses Mount Beak Earlobes (except eyes)

  •  

 

 

Body Parts (Neck, wings, breast, abdomen, shanks, legs, hocks, feet, joints, vent, and skin, abnormalities), skinny body, retarded growth, weight depression

  •  

 

  •  

Feathers abnormalities

  •  

 

 

Feed Consumption Changes

 

  •  

 

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

 

  •  

 

Shell quality

 

  •  

 

Internal Egg quality

 

  •  

 

* Sometimes has not been observed or measured body abnormalities yet or inadequacy of monitoring systems, and even the course time of the disease

*Sometimes has not been observed or measured feathers abnormalities yet or inadequacy of monitoring systems, and even the course time of the disease

*Sometimes has not been observed or measured lameness  yet or inadequacy of monitoring systems, and even the course time of the disease

*Sometimes has not been observed the dead birds yet or depend on the course time of the disease

Causing Agents
Bacterial Infection. Mycobacterium avium serovars 1,2 and 3. Mycobacterium avium serovar 2, the organism most frequently isolated from chickens is rarely isolated from humans.
Affected Systems/Organs
Digestive and Locomotor System. Various organs and tissues. Bones and joints.
Spread
Transmission bird to bird. Droppings. Objects or items contaminated with droppings.
Mainly Affects
Liveability.
Solution
Quarantine. Biosecurity, Hygiene. Disinfection and anything that might be contaminated by their excretions or faeces.
Suggested Actions
  • Can be confirmed with clinical signs and gross lesions
  • Technical assistance recommended
  • Diagnosis should be confirmed with rapid assays and/or a certified laboratory
  • Veterinary intervention is recommended
  • Can be managed with vaccination programs.
  • This is a notifiable disease, veterinary intervention is essential. It is advisable that you run DTECT again to ensure you have answered all the questions correctly. If you suspect that you may have this disease please contact your local authorities immediately.

Impact on Egg quality

0

Impact on Liveability

3


Impact on Production

0

Overall Economic Impact

4



  1. Y.M. Saif.2008.Disease of Poultry. 12th Edition. page 944
  2. David E. Swayne. 2013. Diseases of Poultry 13th Edition. page 1012
  3. Mark Pattison, Paul F. McMullin, Janet M. Bradbury. Dennis J. Alexander. 2008. Poultry Diseases. 6th Edition. 252
  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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