Lameness in poultry

Question 1

What information do you need when you carry out a lameness investigation in poultry?

Answer 1

• No set protocol
• Sometimes there is simply a need to investigate a classical pathological lesion
• Or there can be a performance issue
• DEFINE THE PROBLEM - ie. the producer’s concern
• number of birds on the farm
• Liveweight gain
• Feed conversion efficiencies
• Mortality rates
• Cull rates
• vaccination/medical history
• recent production changes

Question 2

What testing can you run when investigating lameness in poultry?

Answer 2

PM examination

Other testing
* Bloods
* Histology
* Faecal microscopy
* Gut content microscopy
* Electron microscopy
* Virus Isolation
* PCR

X-ray (lixiscope)

Question 3

What is included in a post mortem procedure?

Answer 3

• Weigh the submissions
• Superficial examination
• Systematic approach, don’t forget spinal pathology
• Follow up tests
• Bacteriology; which plates would you use?
• Parasitology

Question 4

Is it helpful to do blood samples on broilers when investigating lameness? If yes, how many birds should be sample?

Answer 4

• The answer is “yes” but we must realise what it represents
• Are antibodies increasing or decreasing?
• Serial samples are much more useful (2 week interval)
• Base line samples on a site can be very useful to establish the “normal” level
• A multitude of tests are available: be selective
• Mycoplasmosis, ORT, Marek’s disease & Gumboro disease serology may all be useful

Number of birds
* 60 samples per group to give 95% confidence that infection of 5% of birds would be detected (Export testing & health programmes)
* 20 – 30 birds for vaccination responses
* 10 – 20 birds to confirm the diagnosis

Question 5

Where should you get a blood sample from a bird?

Answer 5

• Brachial vein exposed by plucking feathers
• Use 21 – 23-gauge needle or nick vein with sharp blade

Question 6

What differentials could explain a bird sitting on hocks with no obvious lesion in the legs and no obvious pain?

Answer 6

• Spondylolisthesis (kinky back)…can feel the deformity at the level of the free vertebra
• Osteomyelitis of the thoracic spine… look for an abscess on the spine on PM

Question 7

What are your 2 differentials when Birds appear to be uncomfortable walking, with bilateral lameness? The bones of the hock joint may appear thickened, and a lot of mild bone deformities may be present. Bones and beak are more malleable than normal. Bone deformity-bowing of the proximal tibiotarsus, with thickened tibiotarsal growth plates.

Answer 7

• Rickets - thickening of all long bone growth plates (confirm with histopath). Due to lack of vitamin D3 or a Ca/P imbalance resulting in a lack of mineralisation
• Tibial dyschondroplasia - thickening of the growth plate of the tibiotarsal bone

Question 8

What is your top differential for the following presentation in birds: Severely lame, difficulty in rising, wings used for support, possible pain on palpation of medial aspect of femur. Severely lame-hot swollen joints and /or tendons
Males more affected than females
Lameness more prevalent in heavier birds. Disintegration of proximal femur.

Answer 8

Femoral head necrosis.

Question 9

What causes femoral head necrosis?

Answer 9

• Immunosuppression
• Bacteria, especially Staphylococcus aureus,
• Reovirus

Question 10

What birds are most likely to suffer from hock infections? What bacteria can cause them? How can they be treated?

Answer 10

• Typically, larger birds affected
• Poor hygiene can be to blame
• Swollen hock joint
• Culture –e.g. Staphylococcus aureus, Escherichia coli, Ornithobacterium rhinotracheale, Enterococcus caecorum and Mycoplasma synoviae
• Antibiotics useful in early lesions

Question 11

What is your top differential when seeing a bird hopping lame with a palpable thickening of the gastrocnemius tendon above the hock joint? What is the cause?

Answer 11

Tendon rupture - Associated with rapid growth and insufficient exercise

Question 12

How can you prevent lameness in poultry?

Answer 12

• Vaccines (commercial & autogenous)
• Diet changes
• Water supplementation
• Stocking levels
• Breed changes
• Husbandry alterations (e.g. Bedding substrate & ventilation)
• Kill schedule

Question 13

How can you prevent pododermatitis in poultry?

Answer 13

• change water systems so there are no leaks
• change bedding
• adjust diet

Question 14

What are common causes of lameness in poultry?

Answer 14

• Femoral head necrosis
• Hock joint infection
• Osteomyelitis
• Tibial dyschondroplasia
• Rickets
• Pododermatitis
• Spondylolisthesis (Kinky back)
• Spinal abscesses