Mortality & Decreased Egg Production in Poultry Flashcards
What are some non-pathological causes of a drop in egg production?
Seasonality (natural decline in laying).
Hens going broody.
Geriatric stock (aging layers)
What are some pathological causes of an egg drop in poultry?
Environmental stress (e.g., temperature extremes, overcrowding).
Flock mortality/morbidity (disease outbreak).
Malnutrition (deficiencies in calcium, protein, vitamins).
Viral diseases (e.g., Avian Influenza, Infectious Bronchitis, Newcastle Disease).
Bacterial infections (e.g., Mycoplasma, Avian Pathogenic E. coli).
Parasitic diseases (internal or external parasites affecting health).
What history and clinical examination steps should be conducted when investigating mortality and egg drop?
Egg production records – Has the drop been sudden or gradual?
Egg quality assessment – Shell texture, color, concentric rings.
Vaccination status – Are birds protected against major diseases?
Clinical examination – TPR (temperature, pulse, respiration), general health check.
What are the key diagnostic tools used in post-mortem examination?
Histology – Tissue analysis for cellular changes.
Bacteriology – Identify bacterial infections.
Serology – Detect immune responses to pathogens.
Virology – Identify viral causes
What are the clinical signs of high-pathogenic avian influenza (HPAI)?
Mortality up to 100% within 36 hours.
Anorexia.
Respiratory signs – Coughing, sneezing, swollen heads.
Nervous signs – Depression, ataxia.
Diarrhoea.
How do clinical signs of low-pathogenic avian influenza (LPAI) differ from HPAI?
Similar but less severe respiratory and nervous signs.
Egg drop.
Blood at nose and cloaca.
What are the clinical signs of Newcastle Disease in poultry?
Respiratory signs – Coughing, sneezing, swollen heads.
Nervous signs – Ataxia, prostration, opisthotonus.
High mortality (similar to AI).
Egg production drop.
Soft-shelled eggs with concentric rings on shell.
What are the key features of Infectious Bronchitis in poultry?
Aetiology – Coronavirus.
Clinical Signs – Sneezing, egg drop, mortality, scouring, huddling.
Post-mortem findings – Tracheitis, swollen kidneys, airsacculitis.
Diagnosis – Serology, PCR, virus isolation.
Prevention – Hygiene and vaccination.
What are the key features of avian rhinotracheitis (swollen head syndrome)?
Aetiology – Pneumovirus (subtypes A & B).
Clinical Signs – Swelling of face/head, nasal discharge, conjunctivitis, sneezing, dyspnea.
Post-mortem lesions – Serous rhinitis, tracheitis, pus in bronchi.
Diagnosis – Serology, virus isolation, PCR.
Prevention – Vaccination with subtype-specific vaccines.
What are the key features of ILT (infectious laryngotracheitis)?
Aetiology – Lifelong latent herpesvirus infection.
Clinical Signs – Upper respiratory signs, sneezing, periocular swelling, egg drop.
Post-mortem findings – Oedema of glottis/larynx, mucus plug.
Prevention – Vaccination in commercial poultry.
How is Mycoplasma gallisepticum diagnosed and managed?
Diagnosis – PCR, culture is difficult, serology useful.
Treatment – Antibiotics (reduce signs but don’t eliminate infection).
Prevention – Biosecurity, sourcing from disease-free breeder flocks.
What are the key clinical signs of APEC (Avian Pathogenic Escherichia coli) infection in poultry?
Respiratory signs, decreased appetite, poor growth, mortality.
High morbidity.
What are common post-mortem lesions seen with APEC infections?
Enteritis, arthritis, synovitis.
Omphalitis, salpingitis, peritonitis.
Perihepatitis, pericarditis, airsacculitis.
What causes egg peritonitis in laying hens?
Normal ovulation occurs, but the oviduct fails to engulf the ova.
The egg yolk enters the coelomic cavity, triggering a foreign body reaction.
Usually sterile ascites, but prone to secondary bacterial infections (e.g., E. coli).
What are the clinical signs of egg peritonitis?
Lethargy, stopped laying.
Upright posture.
Weight gain with reduced appetite.
Dirty vent area.
How is egg peritonitis treated?
Drain ascites (cytology and culture).
NSAIDs (Egg withdrawal for 7 days).
Antibiotics (if needed, culture first; broad-spectrum options include TMPS).
GnRH analog (Suprelorin implant) – Temporarily stops ovulation.
Surgical spay (last resort).
What are some common routes of vaccine administration in poultry?
Drinking water.
Spray (hatchery or on-farm).
Intra-ocular.
In ovo.
Injection.
What considerations should be taken when medicating poultry?
Use the Cascade wisely – Few licensed products exist for poultry.
Owners must keep a medicines book.
Look out for contraindications (e.g., withdrawal periods for eggs).
NSAIDs (e.g., meloxicam) used peri- and post-op.
Butorphanol is more effective than buprenorphine in poultry due to receptor differences.
