Poultry Flashcards
How can history be established when investigating lameness?
Be methodical
FOR BROILERS
- Site identification details
- Age…many conditions are age related
- Age range on site
- Number of birds on farm, in each house, in the affected group
- Nature of the problem i.e. the producer’s concern
- Mortality rates
- Cull rates (separating out leg culls)
- Vaccination/medical history
- Previous crop health and performance figures
- Recent production changes (e.g. New equipment, change in feed ration, breed used)
What should be documented when documenting the normal?
- Number of birds
- Age
- Breed
- Egg production
- Egg quality
- Fertility
- Hatchability
- Daily liveweight gain
- Water consumption
- Mortality
- Cull rate
- Evenness
- Food conversion ratio
- European production efficiency factor
- Performance recording underpins FHP
What tests can be done on PM investigation?
- Bloods
- Histology
- Faecal microscopy
- Gut content microscopy
- Electron microscopy
- Virus Isolation
- PCR
Discuss PM examination of poultry?
- Because of the large numbers of birds kept, mortalities are inevitable
- Post mortem examination of fresh dead allows a unique opportunity to examine the internal organs of the birds
- It is the mainstay of our examinations, but is complemented by other testing
- Sample selection can impact on findings
- Culls vs. Dead
- Average batch size ~ 6 birds
What are the recognised methods of culling?
The Humane Slaughter Association’s guidelines advise neck dislocation
Refer to WATOK (welfare at time of killing)
What is necropsy procedure?
- Weigh the submissions
- Superficial examination
- Systematic approach, don’t forget spinal pathology
Follow up tests
- Bacteriology
- Parasitology
When blood sampling broilers is a snap shot useful?
- 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
What is the blood sampling technique in poultry?
- Good restraint is very important
- Brachial vein exposed by plucking feathers
- Use 21 –23 gauge needle or nick vein with sharp blade
- Half fill blood tube
- Bleeding will usually stop once wing is lowered
- Put cap on tube and lie on side to clot
- Send to laboratory asap (with paperwork)
- DO NOT FREEZE
What are your differential Diagnoses for poultry lameness?
Think:
- Viral
- Bacterial
- Parasitic
- Nutritional
- Genetic
- Metabolic
What is lameness?
Lameness is the consequence of biomechanical or neural dysfunction or pain and is usually a welfare concern.
What do you do if lameness is evident?
In severe cases of lameness the patient should be culled
What is a synsacrum?
Like mammals the pelvis consists of the ischium, ilium and pubis. As previously mentioned it is fused to the synsacrum at the ilium.
The trochanter of the femur articulates with the antitrochanter of the pelvis. This articulation ensures that?
when the leg is in a normal position, abduction is prevented
The more the bird has to run?
The wider the pelvis
Femoral condyles are attached by ligaments to, and articulate with the?
tibiotarsus and the head of the fibula.
The tibiotarsus is formed by the fusion of ?
The tibia and the proximal row of tarsal bones
The fibula is attached to the tibiotarsus by a tight fibrinous union at the fibular crest and extends 2/3 the way down, therefore there is?
little rotation of the leg
The hock is?
The hock is an intertarsal joint between the tibiotarsus and tarsometatarsus. It has a single meniscus and a single cruciate
The tarsometatarsus is a fusion of the?
distal tarsal bones to the 3 main metatarsal bones and extends to the ground. It can be a very long bone in waders
Most birds have digits?
I to IV and they have 2, 3, 4 & 5 phalanges
Anisodactyl birds have?
3 forward facing toes and a single hind toe
Zygodactyl birds have?
digit II and III facing forward and digits I and IV facing backwards
Label the digits in this anisodactyl bird?
Why do ducks waddle?
The hip can be extended and flexed but there is also rotation in the recovery phase. This is pronounced in ducks: hence their waddle. There is very little abduction or adduction
What are the extensors and flexors in the poultry limb?
Extensors= pubo-ischio-femoralis & iliofemoralis (shock absorbers when landing)
Flexors=iliotibialis cranialis
The stifle is flexed and extended by?
flexed by the iliofibularis and extended by the femorotibialis
The hock joint is flexed and extended by what?
flexed by tibialis cranialis and extended by gastrocnemius.
The palpable gastrocnemius tendon passes through a sleeve connected to the caudal surface of the cartilage and ends on the plantar aspect of the tarsometatarsus. (Heavy birds can often develop a “slipped tendon”.)
What allows a bird to perch?
When birds crouch slightly the flexor tendons tense thus allowing perching. There is also a locking mechanism in the digits where the flexor tendons have a ratchet that prevents them moving when the muscle is tensed and the toes are flexed and gripping. Thus when getting a bird of a perch it is made easier if you lift it slightly
What would be you d/dx for this clinical presentation:
Sitting on hocks, no obvious lesion in the legs, no obvious pain?
1. Spondylolisthesis (kinky back)…can feel the deformity at the level of the free vertebra
2.Osteomyelitis of the thoracic spine.
Illustrate a chicken and a turkey vertebral column?
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
What are your 2 differentials?
Rickets
Tibial Dyschondroplasia
What is Rickets?
- Thickening of all long bone growth plates
- confirm with histopathology
- This is an osteodystrophy due to a lack of vitamin D3 or a Ca/P imbalance resulting in a lack of mineralisation. Long bones are soft and pliable and there may also be rickets rosaries
What is tibial dyschondroplasia?
- TD…thickening of the growth plate of the tibiotarsal bone
- The zone of hypertrophied cartilage cells in the proximal end of the tibiotarsal bone fails to become calcified because its blood supply is absent
(Chondrodystrophy-insufficient bone is produced at the cartilaginous growth zone resulting in short bowed bones. Appositional growth is normal, therefore joints can appear swollen. It may be a precursor to slipped tendons. Aetiology maybe nutritional or secondary following a congenital infection…NOT VERY COMMON)
What are these clinical signs likley cause: 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?
Femoral head necrosis
What is the cause of femoral head necrosis?
Immunosuppression
Bacteria, especially Staphylococcus aureus,
Reovirus
Discuss hock infections?
- Typically larger birds affected
- Just prior to slaughter
- Birds go lame first
- Poor hygiene can be to blame
- Swollen hock joint
- Culture –e.g. Staphylococcus aureus Escherichia coli Ornithobacteriumrhinotracheale and Mycoplasma synoviae
- Antibiotics useful in early lesions
What do these clinical signs suggest:
Hopping lame with a palpable thickening of the gastrocnemius tendon above the hock joint
TENDON RUPTURE
Associated with rapid growth and insufficient exercise
How can welfare be assessed?
Five Freedoms
- Freedom from hunger and thirst
- Freedom from discomfort
- Freedom from pain, injury or disease
- Freedom from fear and distress
- Freedom to perform most normal behaviour
Our poultry legal responsibility is outlined in which legislation?
Our legal responsibility is defined by:
- Animal Welfare Act 2006
- Welfare of Farmed Animals (England/Wales) Regulations 2007
- Welfare of Animals (Transport) England Order 2006
- The Welfare of Animals at the Time of Killing (England) Regulations 2015
Name common causes of poultry lameness?
Common causes of poultry lameness:
- Femoral head necrosis
- Hock joint infection
- Osteomyelitis
- Tibial dyschondroplasia
- Rickets
- Pododermatitis
- Spondylolisthesis (Kinky back)
- Spinal abscesses
