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Poultry 2
poultry 2
65
Agriculture
Undergraduate 4
11/24/2014

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Term
What is acute disease?
Definition
rapid onset, short but severe course
Term
What is culling?
Definition
removal from the flock before completing production cycle
Term
What is virulence?
Definition
the degree of pathogenicity, based on severity of disease and ability to invade tissues
Term
What is cage layer disease?
Definition
metabolic disease of laying hens housed in conventional cages due to decreased bone mineral density
Term
What birds are typically affected by cage layer fatigue?
Definition
young laying hens in conventional cages during peak egg laying
Term
What are the clinical signs of cage layer fatigue?
Definition
inability to stand
fragile bones
birds lie down, stop eating
thin egg shells
posterior paralysis
deformed sternum & ribs (soft bones)
acute death
Term
What causes posterior paralysis in cage layer fatigue?
Definition
collapse of vertebrae compresses the spinal cord
Term
Describe the pathogenesis of cage layer fatigue
Definition
Osteoporosis
-Ca, P or D3 deficiencies + lack of activity & load-bearing

Deformed sternum and ribs
-due to poor Ca/P during growth

Acute death
-due to hypocalcemia
Term
True or False

All laying hens have some degree of osteoprosis
Definition
true
Term
Why is osteoporosis a concern?
Definition
inreases risk of leg/wing fracture during loading, transport, processing
Term
How can you prevent cage layer fatigue in pullets?
Definition
-aim for uniform skeletal & reproductive development in flocks
-achieve good skeletal frame by 6 wks of age
-avoid excess Ca until 2 weeks before laying time (increase then)
Term
How can you prevent cage layer fatigue in layers?
Definition
D3 & Ca added to water

oyster shell added to feed (slow Ca release)

newer housing systems with enriched cages, or non-cage systems
Term
What are the functional absorptive cells in the gut? Where are they found?
Definition
enterocytes

-external lining of villi
Term
Describe the etiology of coccidiosis
Definition
-parasitic disease caused by a species of the genus Eimeria
Term
What are the clinical signs of coccidiosis?
Definition
-depression
-ruffled feathers
-diarrhea, mucus or blood in feces
-poor growth, morbidity or mortality varies depending on species of the pathogen
Term
At what stage of the coccidian life cycle does damage begin the to intestinal epithelium?
Definition
2nd Schizont stage

-merozoites are breaking out of cells & invading other cells, can cause lots of tissue damage
Term
What is different in terms of the coccidian life cycle if the parasite infects immune birds?
Definition
the sporozoites remain in the lamina propria, instead of moving to the crypt epithelium to continue their life cycle
Term
Describe the basic coccidian life cycle
Definition
1. Unsporulated oocysts are excreted in feces
2. Oocysts sporulate outside of the hose within 2 days, are then ingested
3. Sporocysts are released in intestine
4. Sporozoites are released, infect enterocytes, undergo asexual reproduction
Term
True or False

Unsporulated oocysts are infective
Definition
False

Not infective until they sporulate and are then ingested
Term
What species of coccidia affects the upper portion of the intestine? What are the characteristics of infection?
Definition
Eimeria acervulina

-mild disease, low mortality, reduced production parameters
Term
What species of coccidia affects the middle portion of the small intestine? What are the characteristics of infection?
Definition
Eimeria necatrix & Eimeria maxima

-severe, can cause significant mortality & decrease production parameters
Term
What species of coccidia affects the ceca? What are the characteristics of infection?
Definition
Eimeria tenella

-severe hemorrhage and very high mortality
Term
What is the economical significance of coccidiosis?
Definition
-costs of prevention
-reduced growth rates
-reduced production
-mortality
Term
What are the risk factors associated with coccidiosis?
Definition
Host
-age (young) & immunity (poor nutrition)

Environmental
-wet litter (oocysts survive well)
-poor barn conditions causing birds to be chilled
Term
What causes coccidiosis to spread?
Definition
-most commonly transmitted mechanically (indirect) via employee clothing, equipment, vehicles moving between barns

-oocysts can survive for several months in environment

-at highest level in droppings when birds are 3-5wks old
Term
True or False

Coccidia can be transmitted from wild birds to broiler chickens
Definition
False

the parasites are extremely host specific
Term
How can you prevent/control coccidiosis through management?
Definition
-good biosecurity
-remove litter between flocks, clean barn thoroughly to reduce number of oocysts
-good litter quality
-proper ventilation
-conventional cages that separate birds from feces = fewer infections
Term
True or False

Thorough disinfection is a good means of preventing coccidiosis
Definition
False

disinfectants do not kill oocysts
Term
How can you prevent/control coccidiosis through vaccination? What is a commonly used vaccine against coccidiosis?
Definition
-provide low level exposure to oocysts of common species to develop species-specific immunity in the birds

-spray chicks in hatchery in 1st day of life
-vaccinate through feed on from 1-4 days old

Coccivac-B
Term
Is Coccivac-B a killed or modified live vaccine?
Definition
modified live
Term
How can you prevent/control coccidiosis through medication?
Definition
shuttle programs: using two or more products during grow-out of flock

rotation: rotating between types of drugs as flock ages e.g. every 4 months

-both programs help to prevent development of resistance to anticoccidials

-must respect drug withdrawal times!
Term
Describe the etiology of necrotic enteritis (4 points)
Definition
-enteric disease of chickens & turkeys

-caused by alpha toxin produced by Clostridium Perfringens Type A or Type C

-most common in broiler chickens 2-5 wks of age

-gram positive rods on gram stain
Term
What are the clinical & subclinical signs of necrotic enteritis?
Definition
-depression
-dehydration
-ruffled feathers
-diarrhea
-sudden death

Subclinical: reduced growth rate & feed consumption/conversion efficiency
Term
Describe the pathogenesis of necrotic enteritis
Definition
-overgrowth of clostridia in intestinal lumen
-guts become thickened
-anaerobic conditions cause toxin production
-toxin causes severe necrosis of enterocytes
-necrosis begins at tips of villi, eventual entire villous will be destroyed
Term
What is considered one of the most economically important diseases of commercial broiler chickens?
Definition
necrotic enteritis
Term
What is the impact of necrotic enteritis?
Definition
-1% flock mortality per day for several days
-death of up to 50% if untreated
-culling, reduced growth rate, condemnation of carcasses at processing due to secondary liver lesions
Term
What are the risk factors associated with NE?
Definition
Host: age, immunity, strain

Environment:
-coccidosis predisposes
-stocking density, wet litter
-buildup of bacteria (farm history)
-feed ingredients & nutrient content
Term
What type of diet would predispose a bird to necrotic enteritis?
Definition
high fat content, wheat/barley based
Term
How can you prevent/control NE?
Definition
-reduce stress
-ventilation, litter quality, stocking density, lighting
-wood shavings more absorbent than straw
-thorough cleaning between flocks
-vaccinate/medicate to control coccidiosis
-in feed microbials to prevent/treat outbreaks
Term
True or False

Necrotic enteritis can be prevented through vaccination
Definition
False
Term
Describe the etiology of infectious bronchitis
Definition
acute, highly contagious respiratory disease caused by infectious bronchitis virus

several variations of the pathogen, with varying virulence
Term
What type of virus is IBV?
Definition
coronavirus
Term
What is 'special' about strain 4/91 of IBV?
Definition
It is a genotype which has only recently been discovered in Canada, and is not a canadian/US variant. Discovered here in 2011.

higher mortality than other strains
Term
Describe the general clinical signs of IB
Definition
-depend on age, immune status & virulence of virus

-can be asymptomatic, up to involving respiratory, renal & reproductive organs
Term
Describe the clinical signs of IB in chicks
Definition
-depression, ruffled feathers, huddling near heat
-coughing, sneezing, nasal discharge, gasping within 24hrs
-conjunctivitis, ocular discharge, tearing, swollen sinuses
-reduced feed intake, poor weight gain (maybe)
Term
Describe the clinical signs of IB in older birds
Definition
-similar signs as chicks but less severe, possibly only observable at night when birds are quiet
-egg production reduced up to 50%
Term
Describe the clinical signs of IB in eggs
Definition
-disrupted Ca deposition due to IBV presence in repro tract leads to shoft shelled, shell-less or misshapen eggs
-abnormal colour & texture
-thin watery egg white, lack of separation between thick & thin albumen
Term
Describe the renal clinical signs of IB
Definition
-birds recover from early respiratory signs but later develop diarrhea, sometimes fatally blocking renal system
Term
Describe the spread of IB
Definition
-shed in nasal excretions & feces
-spreads via direct & indirect contact
-internal organs may be persistently affected, so some birds shed intermittently (carriers)
Term
Describe the impacts of IB
Definition
-reduced egg production, abnormal eggs
-recovered hens may never return to normal production levels
-inhibited production performance in broilers
-secondary infection likely to occur
-high morbidity, relatively low mortality
-chicks <2 wks old may have permanent oviduct damage
Term
What are the risk factors associated with IB? (8)
Definition
Host
-species (chickens only)
-young chicks
-older birds (more repro lesions)

Environment
-concurrent infection with other pathogens/ immunosuppression viruses
-high stocking density
-chilled birds
-poor ventilation & high ammonia

Renal strains: breed, high protein diet
Term
What are some of the aspects of prevention & control of IB?
Definition
-highly infectious, biosecurity is a challenge
-thorough C&D with downtime
-always move employees from younger flocks to older ones
-attenuated live vaccines in drinking water or by spray
-IM/sub-cu inactivated oil-emulsion vaccines for breeders & layers before production cycle
Term
True or False

A single vaccine provides sufficient protection against all strains of IB
Definition
False

-no cross-protection between serotypes
Term
Why would a disease be classified as reportable?
Definition
significant importance to human/animal health, or Canadian economy
Term
Name 2 reportable poultry diseases
Definition
Fowl Typhoid
Pullorum Disease
Newcastle Disease
Avian Influenza
Term
What bacteria causes Fowl Typhoid disease and what poultry does it affect?
Definition
Salmonella Gallinarum
-clinical disease in growers/adult birds
-affects chickens, turkeys & minor poultry

-high mortality
Term
What bacteria causes Pullorum disease and what poultry does it affect?
Definition
Salmonella Pullorum
-clinical disease in young chicks

-high mortality
Term
How are Fowl Typhoid and Pullorum transmitted? How do we test for them?
Definition
from parent to offspring through the egg

-fluff samples collected at hatchery & tested
Term
What causes Newcastle Disease? Which forms are most virulent?
Definition
avian paramyxovirus

volegenic forms
Term
True or False

All forms of Newcastle Disease are reportable
Definition
False

volegenic forms are reportable
Term
What are the clinical signs of Newcastle disease? (5)
Definition
-hemorrhage in intestinal tract
-conjunctivitis, swelling of eyelids, ocular discharge
-neurological signs
-hemorrhage in intestinal tract
-high mortality
Term
True or False

Newcastle Disease has potential to be zoonotic
Definition
true
Term
What causes Avian Influenza? What are its characteristics?
Definition
orthomyxovirus type A influenza virus

-respiratory & nervous signs, sudden death
-swelling & hemorrhage of comb & wattles
Term
What are the primary reservoirs/sources of introduction of Avian Inluenza onto poultry farms?
Definition
waterfowl / wild birds
Term
How is avian influenza prevented?
Definition
tight biosecurity!
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