bok bok Flashcards
AV01-05
name 4 important health principles of commercial poultry flocks
- achieve production targets
- achieve welfare targets
- freedom from zoonosis
- freedom from residues
what is the target length of time to keep broilers for?
32-48d
what is the target length of time to keep breeder birds for?
60 weeks
what is the target length of time to keep layers (birds) for?
72 weeks
what is the production target for broiler birds?
2.2-3.8kg
what is the production target for breeder birds?
150 hatching eggs
(80% hatchability)
what is the production target for layer birds?
300 eggs
name the 2 processes of biosecurity barriers on commercial poultry farms
- keep disease out
- stop it spreading between flocks if it gets into a site
what type of production system do you want on a commercial poultry unit
all-in/all-out
how long must people be poultry-free before coming to a commercial poultry unit
72h
(no contact with poultry outside of premises)
name 4 ways of monitoring disease on commercial poultry units
- serology/PCR
- bacteriology
- TVCs
- Post mortems
name 5 methods of administrating vaccines on commercial poultry units
- injection
- eye-drop
- drinking water
- on feed
- spray
where are injectable killed vaccines injected in poultry?
breast muscle or leg
this is the most common injectable live vaccine used in poultry
(often done by robots in the hatchery)
Marek’s disease
what type of live vaccines are common given via water administration?
for respiratory diseases
this vaccine for poultry requires frequent admin to maintail local immunity
IB (infectious bronchitis)
name the respiratory disease of poultry
highly infectious coronavirus with many different variants (defined by S protiein);
variants 793B & Qx common in UK;
infection starts in trachea, virus may reach bloodstrea and spread to oviduct and kidney if not stopped by antibodies;
secondary E. coli infections common;
shed in resp tract and faeces, NO vertical transmission
Infectious Bronchitis (IB)
name 5 clinical signs of infectious bronchitis (IB) in commercial layers
- drop in egg production
- thin-shelled/pale/misshapen eggs
- respiratory signs
- blind later pathology
- kidney damage
how to diagnose infectious bronchitis (IB) in commercial layers?
clinical signs and PM
or RT-PCR
(serology not helpful as vaccinated birds can have high Ab titers)
name the respiratory disease of commercial layers
highly contagious virus affecting chickens, turkeys and ducks;
subtypes A, B, C, & D;
easily killed by disinfectants;
infection exacerbated by poor ventilation, high stocking density, stress, co-infection with E. coli, ORT, MG
avian metapneumovirus (aMPV)
how is avian metapneumovirus (aMPV) spread?
in resp secretions
(NOT faeces)
name 3 clinical signs of avian metapneumovirus (aMPV) in commercial layers
- swollen head syndrome
- decline in egg numbers
- reduced eggshell quality
(chickens may be asymptomaic)
name 4 clinical signs part of ‘swollen head syndrome’ seen with avian metapneumovirus (aMPV)
- sinusitis
- frothy eyes
- nasal discharge
- torticollis
name the respiratory disease of commercial layers
highly contagious herpesvirus which causes a latent infection;
svere resp signs, reduced egg production, sudden death if a blood/mucus/pus blocks trachea;
control with a single live vaccination in-rear, or vector vaccine at day-old
(more common in backyard chickens than commercial)
infectious laryngotracheitis (ILT)
name the respiratory disease of commercial layers
bacteria without cell walls;
can be transmitted vertically & horizontally;
establish a latent infection;
common on multi-age sites
mycoplasma
name the Mycoplasma species
chickens, game birds, turkeys, most avian species;
contributes to chronic resp disease (CRD) in broilers;
conjunctivitis and sinusitis;
reduced flock performance;
co-infections with IB, TRT, Ms;
can lead to pericarditis, perihepatitis, air sacculitis with E. coli in broilers
Mycoplasma gallisepticum (Mg)
name the Mycoplasma species
chickens, game birds, turkeys, most avian species;
usually milder clinical signs than Mg;
glassy topped eggs;
lameness, reduced flock performance;
co-infections with IB, TRT, Mg;
incr susceptibility to E. coli peritonitis ;
swollen joints
Mycoplasma synoviae (Ms)
what is the gold standard (but expensive) method of diagnosing Mycoplasma in poultry
culture and MIC testing
name the disease affecting commercial layers
main cause of mortality in commercial laying flocks in the UK;
frequently occurs at two periods during lay:
1. as birds are reaching peak production
2. >50wks (age-related decline in immunity)
infection via resp tract or via vent;
once inside body cavity will cause peritonitis, airsacculitis, septicaemia, death
E. coli peritonitis syndrome
name 5 predisposing factors for E.coli peritonitis syndrome in birds
- poor air quality
- other resp pathogens
- flock stressed/immune compromised
- poor gut helth
- high levels of vent pecking/cannibalism in flock
what antibiotic can be used to treat E.coli peritonitis syndrome in commercial layers (0 egg withdrawal)
oxytetracycline
name the disease affecting commercial layers
reservoirs of infection are wild birds, livestock, rodents, cats;
peracute: sudden death, congested carcass
acute: depression, anorexia, cyanosis, diarrhoea, mucus discharges
chronic: depression, conjunctivitis, dyspnoea, swollen wattles, torticollis, lameness
Pasturellosis / Fowl Cholera
(P. multocida)
name 4 PM pathologies seen with peracute/acute Pasturellosis in commercial layers
- congested carcass
- petechiation
- necrotic foci liver
- lung oedema
name 3 PM pathologies seen with chronic Pasturellosis in commercial layers
- caseous joint lesions
- perihepatitis and pneumonia
- swollen wattles
name the disease affecting commercial layers
sources: pigs, sheep, rodents, long survival in soil;
infection by skin lesions, consumption of infected material (cannibalism), red mite;
acute: depression, inappetance, congested extremities, sudden death;
chronic: cutaneous lesions, swollen hocks;
ZOONOTIC
erysipelas
(Erysepelothrix rhusiopathiae)
what drug will reduce mortality in layers due to erysipelothrix in short term, but disease usually returns
penicillin
name the disease affecting commercial layers
widespread and highly contagious herpesvirus;
assume its present in every chicken flock;
horizontally transmitted;
transforms T-cells causing immunosuppression and neoplastic changes in liver, spleen and nervous system;
infection from inhalation of skin and feather dust from other poultry
Mareks Disease
clinical signs of Mareks Disease are generally not seen before this age of birds
8wks
(most commonly detected at 12-24wks)
name 2 clinical signs of the classical form of Mareks Disease
- ataxia
- paralysis (esp of wings and legs)
name the disease affecting commercial layers
cause erythroid, lymphoid and myeloid leucosis and a variety of other tumours;
strains A, B, C, D, E, J;
subclinical may depress performance;
lymphoid is most common and usually in layer type birds
Avian Leucosis (ALV)
name the endoparasite of commercial layers
earthworms and house flies paratenic hosts;
eggs may also be ingested directly from soil;
prepatent period = 4wks, eggs may remain infective in soil for many years;
limited pathological significance but important role in transmission of Histomonas meleagridis
Heterakis
name the endoparasite of commercial layers
direct life cycle;
prepatent period = 5-8wks;
largest nematode pathogen found in poultry;
clinical signs most severe in birds aged under 3mo;
inappetence, diarrhoea, dehydration, stunted growth, dullness, misshaped and/or soft thin shelled eggs
Ascarids
name the endoparasite of commercial layers
direct life cycle;
most important intestinal nematode parasite in chickens;
weight loss, diarrhoea, regurgitation, anaemia and oral necrotic plaques when present in high numbers
Capillaria
(Capillaria obsignata)
how often should faecal worm egg counts be done in commercial layer flocks?
4-6wks
name 4 licensed wormers for chickens with 0 egg withdrawal
- Gallifen (fenbendazole)
- Panacur Aquasol (fenbendazole)
- Flimabend (flubendazole)
- Flubenvet (flubendazole)
what is the scientific name for Red Mite?
Dermanyssus gallinae
name the ectoparasite affecting commercial layers
very common and most damaging parasite of laying hens worldwide;
lifecycle can be as short as 10d in warm weather;
visible to the naked eye;
colonies live within the poultry house and only become active at night
Red Mite (Dermanyssus gallinae)
name the red mite control method
dehydrates and abrasively destroys mites in the environment
Diamatacious eart
name the red mite control method
spray-on products - kill mites in the environment
Pyrethroid-based
name the red mite control method
in-water - kill mites on host & 0 egg withdrawal;
expensive and only suitable for treating larger flocks
Exzolt (fluralaner)
name the disease of gamebirds
commonly seen from 2-10wks;
dull, depressed, enteritis, weight loss;
exacerbated by overstocking, stress, damp conditions, dirty water;
diagnosis by wet prep exam of intestinal scrapes;
Avatec used in feed, toltrazuril or amprolium in water
coccidiosis
name the disease of gamebirds
single cell motile protozoa, infection likely by faecal-oral route;
commonly seen from 4-14wks;
dullness, rapid wasting, enteritis (often yellow bubbly droppings);
diagnosis by wet prep exam of intestinal scrapes from FRESHLY CULLED birds;
treatment with Tiamulin plus Doxycycline
Hexamita / Spironucleus
name the disease of gamebirds
horizontal and vertical transmission;
widespread in parent stock and exists in carrier state;
classical ‘swollen head syndrome’, dullness;
outbreaks usually associate with stress;
treatment with abx will only suppress clinical signs
Mycoplasma gallisepticum
name the disease of ducks
types 1-3 which are antigenetically different;
mortality can reach 90% in a young naive flock, and generally presents as sudden death;
control by vaccination of breeders
Duck Viral Hepatitis
name the disease of ducks
presents acutely as haemorrhagic eneteritis, ataxia and death;
associated with contact with natural water sources or wild waterfowl;
control by vaccination, C&D, biosecurity
Duck Viral Enteritis
name the disease of ducks
bacterial disease causing respiratory signs, ataxia and mortality;
controlled by abx treatment, vaccination, improved hygiene/biosecurity
Riemerella anatipestifer
name the disease of turkeys
associated with caecal cores and circumscribed hobnail lesions on the surface of the liver;
intermediate hosts are Heterakis worms;
Tx can be difficult and involves thorough C&D at turnaround, routine worming and use of abx
Blackhead (Histomonas meleagridis)
name the 4 main differential diagnoses for highly pathogenic avian influenza (HPAI)
- erysipelas
- pasteurella
- avian pathogenic e. coli
- newcastle disease
name the 2 most common strains of Newcastle Disease
- Viscerotrophic velogenic (haemorrhages in intestinal tract)
- Neurotrophic velogenic (resp and nervous signs)
where is the initial replication for velogenic Newcastle Disease?
within intestine
what does poor litter with a wet and alkaline surface cause in broilers?
pododermatitis
necrotic enteritis in broilers is caused by entertoxaemia associated with the overgrowth of what pathogen?
Clostridium perfringens
name 4 clinical signs seen with necrotic enteritis in broilers
- inappetance
- dullness
- sometimes diarrhoea
- necrosis of intestinal villi
what drug can be used as an effective treatment for necrotic enteritis in broilers
amoxicillin
name the 4 main species of importance causing coccidiosis in broilers
- E. acervulina
- E. maxima
- E. mitis
- E. tenella
how many days does the coccidia lifecycle take?
5 days
how to treat/control coccidiosis in broilers?
in-feed anti-coccidial program for broilers
name 2 drugs that are effective against all species of coccidia in broilers
- Ionophores (Narasin)
- synthetic chemicals (Nicarbazin)
this is a change in the normal bacterial flora of a broiler
dysbacteriosis
name 5 clinical signs of dysbacteriosis in broilers
- foamy droppings
- fluctuations in water intake
- inappetance
- unevenness
- wet litter
what is the treatment for dysbacteriosis in broilers
amoxicillin
name 3 diseases associated with Fowl Adenoviruses (FAdVs)
- inclusion body hepatitis (IBH)
- hepatitis hydropericardium syndrome (HHS)
- gizzard erosion
this is disease in broilers caused by a natural toxin produced by a fungus, usually as a result of toxin-producing fungi growing in feed
mycotoxicosis
name 3 ways mycotoxicosis may present in broilers
- oral ulcers and crusts on palate or tip of tongue
- poor enteric health
- rapid drop in feed intake
name the 2 most common causes of viral enteritis in broilers
- Reovirus
- Rotavirus
name the pathogen causing viral enteritis in broilers
more likely to cause pancreatic atrophy with fibrosis of the pancreas;
these birds will fail to produce sufficient pancreatic enzymes for adequate digestion
Reovirus
name the pathogen causing viral enteritis in broilers
will typically cause the gut to appear thin walled with very watery contents;
may be gas accumulation in the caeca;
birds are often stunted in growth;
caecal contents may be pale and foamy;
microscopic exam of the guts shoes stunting of villi and reduction in crypts
Rotavirus
what phase is most of the broilers life spent in?
brooding phase
name the disease of broiler chickens
aka Gumboro or IBD or IBDV;
not vertical;
tough virus resistant to disinfectants etc;
knocks out multiphying B cells causing permanent immune suppression if less than 3w old OR viraemia with fever, diarrhoea, mortality and temporary immune suppression if 3-6w
infectious bursal disease (IBD)
name the organ in chickens
home of the B-cell;
antibody production;
physiological atrophy as bird grows;
atrophy due to stress, MDV, IBDV, etc
The Bursa of Fabricius
name the virus causing infectious bursal disease (IBD)
DS RNA in 2 segments;
tough capsid shell 60-70nm;
VP2 (glycosylated, virus neutralising epitopes);
VERY resistant to heat and disinfectants
Avibirnavirus
this is due to increased R ventricular load and subsequent failure in broilers
ascites
name 4 causes of ascites in broilers
- reduced oxygen availability
- elevated CO2
- incr resp demand
- pulmonary hypertension
name 3 common non-infectious skeletal problems seen in broilers
- rotational (torsional) and angular (valgus/varus) deformity
- dyschondroplasia
- rickets
name 3 common infectious skeletal problems of broilers
- Staphyloccocosis
- Reovirus
- Mycoplasma
name the skeletal problem in broilers
absolute or relative deficiency of calcium or phosphorus or insufficient vitamin D;
malabsorption;
flexibility of long bones;
marginal or sub-clinical rickets may go unreported, but may be associated with poor chick performance
Rickets
how to control rickets in broilers?
adquate Calcium and Phosphorus in diet (correct ratio)
name the 3 main places Staphylococcosis can be isolated from when causing skeletal disease in broilers
- proximal femur
- proximal tibiotarsus
- hock or stifle joint
name the cause of lameness in broilers
ulceration of the metatarsal and digital footpads;
wet or poor quality litter is the common cause, a biotin deficiency will also cause it;
frequently scored in flocks or at the abattoir and used as an outcome measure of welfare
plantar pododermatitis
this is a common cause of human food poisoning, does NOT cause pathology in birds;
infected birds remain carriers for several weeks;
faecal shedding appears to increase with stress
Campylobacter
how many birds should be used for PM to investigate a problem?
5-10
which bone in the bird contains continuations of the airsacs
right humerus
which bone in a hen laying eggs contains ‘medullary bone’ a highly labilr form of bone available for egg shell formation;
only present in birds with active ovaries and producing eggs
left humerus
what is dark breast muscle on a bird during PM suggestive of?
dehydration or septicaemia
the liver of a bird should be no bigger than this part of the body
no bigger than the rib cage
name 3 conditions enlargement of a bird’s liver during PM could suggest
- Mark’s
- septicaemia
- other bacterial infection
name 2 conditions congested livers in birds can be associated with
- septicaemia
- heart failure
chickens only have 1 active ovary, which side is it on?
left
