Term
|
Definition
| rapid onset, short but severe course |
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Term
|
Definition
| removal from the flock before completing production cycle |
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Term
|
Definition
| the degree of pathogenicity, based on severity of disease and ability to invade tissues |
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Term
| What is cage layer disease? |
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Definition
| metabolic disease of laying hens housed in conventional cages due to decreased bone mineral density |
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Term
| What birds are typically affected by cage layer fatigue? |
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Definition
| young laying hens in conventional cages during peak egg laying |
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Term
| What are the clinical signs of cage layer fatigue? |
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Definition
inability to stand
fragile bones
birds lie down, stop eating
thin egg shells
posterior paralysis
deformed sternum & ribs (soft bones)
acute death |
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Term
| What causes posterior paralysis in cage layer fatigue? |
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Definition
| collapse of vertebrae compresses the spinal cord |
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Term
| Describe the pathogenesis of cage layer fatigue |
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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 |
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Term
True or False
All laying hens have some degree of osteoprosis |
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Definition
|
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Term
| Why is osteoporosis a concern? |
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Definition
| inreases risk of leg/wing fracture during loading, transport, processing |
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Term
| How can you prevent cage layer fatigue in pullets? |
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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) |
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Term
| How can you prevent cage layer fatigue in layers? |
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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? |
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Definition
enterocytes
-external lining of villi |
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|
Term
| Describe the etiology of coccidiosis |
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Definition
| -parasitic disease caused by a species of the genus Eimeria |
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Term
| What are the clinical signs of coccidiosis? |
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Definition
-depression
-ruffled feathers
-diarrhea, mucus or blood in feces
-poor growth, morbidity or mortality varies depending on species of the pathogen |
|
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Term
| At what stage of the coccidian life cycle does damage begin the to intestinal epithelium? |
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Definition
2nd Schizont stage
-merozoites are breaking out of cells & invading other cells, can cause lots of tissue damage |
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Term
| What is different in terms of the coccidian life cycle if the parasite infects immune birds? |
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Definition
| the sporozoites remain in the lamina propria, instead of moving to the crypt epithelium to continue their life cycle |
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Term
| Describe the basic coccidian life cycle |
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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 |
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|
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 |
|
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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 |
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Term
True or False
Coccidia can be transmitted from wild birds to broiler chickens |
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Definition
False
the parasites are extremely host specific |
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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 |
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|
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 |
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|
Term
| Is Coccivac-B a killed or modified live vaccine? |
|
Definition
|
|
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 |
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|
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 |
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|
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 |
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|
Term
| What is considered one of the most economically important diseases of commercial broiler chickens? |
|
Definition
|
|
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 |
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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
|
|
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
|
|
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 |
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|
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
|
|
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
|
|
Term
| How is avian influenza prevented? |
|
Definition
|
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