Practical 2 - Layers Flashcards by Hege Osland

Name diseases of laying poultry

Respiratory diseases
Inflammatory-necrotic foci
Tumours
Fatty infiltration of the liver
Anaemia
Cannibalism
Lesions of the ovary and oviduct
Diseases connected to egg building
Calcium tetany
Caged layer fatigue

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At which age does the egg-laying start?

16-18 week of age

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At which age does the egg-laying end?

65-70 weeks of age, some up to 90 weeks of age.

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Name respiratory disease of laying poultry

Same as broiler chickens
Infectious laryngotracheitis
Infectious coryza

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What is infectious laryngotracheitis?

is an acute, highly contagious, herpesvirus infection

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What causes infectious laryngotracheitis?

Herpesviridae
Alphaherpesvirinae
Iltovirus
Gallid herpesvirus type 1 (GaHV‐1)

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What is the pathogenesis of Infectious laryngotracheitis?

In flock it is aerogenic and its transmitted by droplets.

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What are clinical signs of Infectious laryngotracheitis?

Upper respiratory symptoms such as noisy breathing and they keep their beak open

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Pathological findings of Infectious laryngotracheitis

Rhinitis and laryngotracheitis

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What is Infectious coryza?

It is an acute respiratory disease

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What causes Infectious coryza?

Avibacterium paragallinarum

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What is the pathogenesis of Infectious coryza?

In flock it is transmitted through inhalation

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Clinical signs of Infectious coryza

Nasal dicsharge and conjunctivitis

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What is the first symptom of Infectious coryza?

Conjunctivis

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What are pathological findings of Infectious coryza?

Conjunctivitis and sinusitis

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Name diseases that can cause Inflammatory-necrotic foci in the livers of laying hens

Septicemia
Tuberculosis
Coligranulomatosis

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Which diseases can cause septicemia?

campylobacteriosis
salmonellosis
fowl cholera

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What is tuberculosis?

chronic bacterial infection

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Which virus causes tuberculosis in laying hens?

Mycobacterium avium subspecies avium

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What is the pathogenesis of tuberculosis?

It is transmitted by inhalation. There are primary lesions in the intestines and foci in the bone marrow.

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Clinical signs of tuberculosis

Emaciation and anaemia, and other symptoms according to which organs the lesions are.

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which pathological findings can we observe in case of tuberculosis?

Foci in different sizes.
Ziehl-Neelsen negative

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What is Coligranulomatosis?

It is an infectious disease caused by a coliform bacillus

In which disease of laying hens is escherichia coli involved?

– Omphalitis
– Septicaemia
– Swollen head syndrome
– Chronic Respiratory Diseases (CRD)
- Coligranulomatosis

What are the pathological findings of Coligranulomatosis?

Foci of smaller sizes Not present in the bone marrow Ziehl-Neelsen negative

Name tumours of non-infectious origin

mesothelioma

Name tumours of infectious origin and which virus they are caused by:

Leukosis/sarcoma group = Retroviridae Marek’s disease = Herpesviridae Reticuloendotheliosis = Retroviridae

What is fatty infiltration of the liver?

It is characterized by a sudden mortality, a decrease in egg production and large amounts of fat in the liver found during necropsy

Name a disease of Fatty infiltration of the liver

Fatty liver hemorrhagic syndrome (FLHS)

In which type of poultry does Fatty liver hemorrhagic syndrome (FLHS) occur?

In layers, and sometimes broilers

What are some causes of Fatty liver hemorrhagic syndrome (FLHS)?

» Lack of lipotropic factors » High‐energy diets » Restricted exercise » Most common during hot weather

What are clinical signs of Fatty liver hemorrhagic syndrome (FLHS)?

Can also be seen as pathological findings: » Higher concentrations of estradiol in the plasma » Fragile, degenerated liver

What is the consequence of Fatty liver hemorrhagic syndrome (FLHS)?

Rupture of the liver and bleeding into the body cavity

What is anaemia?

It is lack of enough healthy red blood cells to carry adequate oxygen to your body's tissues

Name some causes of anaemia in laying hens:

– Feed containing mycotoxins – Ectoparasitic infection = Ectoparasitosis – Bleeding

where can we find damages when consuming feed contaminated with mycotoxins?

- Bone marrow - Kidney - Liver - Heart - Oral cavity + beak (necrosis) - Immunosupression We can also see: - Decreased feed utilization - Decreased weight gain - Decreased egg production

Name two ticks than can cause Ectoparasitosis of laying hens

Fowl tick and poultry red mite

When is it more common for the ticks to feed?

They hide in the crevices during the day and feed at night.

Which disease is caused by ticks?

Lime leg disease

What is cannibalism in laying hens?

A bird begins picking the feathers, comb, toes or vent of another bird. Once an open wound or blood is visible on the bird, the vicious habit of cannibalism can spread rapidly through the entire flock

What are causes of cannibalism?

– overcrowding – malnutrition – inappropriate nests

What can cause lesions on the ovaries and the oviduct?

- Degeneration of the follicles - Salpingitis

Which bacteria will cause degeneration of the follicles?

Salmonella, Mycoplasma, E. coli

How does the degeneration of the follicles occur?

The bacteria settles in the ovaries. In the egg laying season the ovaries becomes active and the building of the follicles start. The bacteria proliferate in the follicular content and we have a degeneration of the follicle

What is a complication of degeneration of the follicles?

Rupture of the follicles will cause serositis in the body cavity

What is Salpingitits?

It is an inflammation of the oviduct, which may contain liquid or caseous exudate

What causes Salpingitis?

It can occur due to an ascending infection from the cloaca or due to haematogenous infection

What are some comlications of Salpingitis?

- Inflammatory exudate accumulates in the oviduct – Antiperistaltic movement – Serositis in the body cavity = Peritonitis - Egg pseudoconcretions

What is Egg pseudoconcretions?

The egg becomes hard, compact mass of matter. We can see a layered fibrin around the egg which has stopped developing

Name some physiological abnormalities that are connected to egg building

– Osteothesaurismosis (=osteomyelosclerosis) – Extramedullary hematopoiesis

Name some abnormalities that are connected to building of the egg shell:

» Calcium deposition in the egg shell » Changes in the calcium level of the blood

What is calcium tetany?

It is a condition due to lower levels of calcium

What causes calcium tetany in laying hens?

Hypocalcaemia

What is Caged layer fatigue?

the equivalent of osteoporosis in chickens

When does Caged layer fatigue happen and who is more prone?

Happens in laying hens that are caged, and normally at the end of the egg production cycle

Clinical signs of Caged layer fatigue:

* Osteoporosis * Spontaneous fractures * Compression of the spinal cord or nerves * Paralysis