Term
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Definition
rapid onset, short but severe course |
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Term
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Definition
removal from the flock before completing production cycle |
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Term
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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 |
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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 |
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Definition
False
Not infective until they sporulate and are then ingested |
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Term
What species of coccidia affects the upper portion of the intestine? What are the characteristics of infection? |
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Definition
Eimeria acervulina
-mild disease, low mortality, reduced production parameters |
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Term
What species of coccidia affects the middle portion of the small intestine? What are the characteristics of infection? |
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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? |
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Definition
Eimeria tenella
-severe hemorrhage and very high mortality |
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Term
What is the economical significance of coccidiosis? |
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Definition
-costs of prevention -reduced growth rates -reduced production -mortality |
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Term
What are the risk factors associated with coccidiosis? |
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Definition
Host -age (young) & immunity (poor nutrition)
Environmental -wet litter (oocysts survive well) -poor barn conditions causing birds to be chilled |
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Term
What causes coccidiosis to spread? |
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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? |
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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 |
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Definition
False
disinfectants do not kill oocysts |
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Term
How can you prevent/control coccidiosis through vaccination? What is a commonly used vaccine against coccidiosis? |
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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? |
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Definition
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Term
How can you prevent/control coccidiosis through medication? |
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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! |
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Term
Describe the etiology of necrotic enteritis (4 points) |
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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? |
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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 |
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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? |
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Definition
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Term
What is the impact of necrotic enteritis? |
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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? |
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Definition
Host: age, immunity, strain
Environment: -coccidosis predisposes -stocking density, wet litter -buildup of bacteria (farm history) -feed ingredients & nutrient content |
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Term
What type of diet would predispose a bird to necrotic enteritis? |
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Definition
high fat content, wheat/barley based |
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Term
How can you prevent/control NE? |
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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 |
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Term
True or False
Necrotic enteritis can be prevented through vaccination |
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Definition
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Term
Describe the etiology of infectious bronchitis |
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Definition
acute, highly contagious respiratory disease caused by infectious bronchitis virus
several variations of the pathogen, with varying virulence |
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Term
What type of virus is IBV? |
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Definition
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Term
What is 'special' about strain 4/91 of IBV? |
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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 |
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Term
Describe the general clinical signs of IB |
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Definition
-depend on age, immune status & virulence of virus
-can be asymptomatic, up to involving respiratory, renal & reproductive organs |
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Term
Describe the clinical signs of IB in chicks |
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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) |
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Term
Describe the clinical signs of IB in older birds |
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Definition
-similar signs as chicks but less severe, possibly only observable at night when birds are quiet -egg production reduced up to 50% |
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Term
Describe the clinical signs of IB in eggs |
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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 |
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Term
Describe the renal clinical signs of IB |
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Definition
-birds recover from early respiratory signs but later develop diarrhea, sometimes fatally blocking renal system |
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Term
Describe the spread of IB |
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Definition
-shed in nasal excretions & feces -spreads via direct & indirect contact -internal organs may be persistently affected, so some birds shed intermittently (carriers) |
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Term
Describe the impacts of IB |
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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) |
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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 |
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Term
What are some of the aspects of prevention & control of IB? |
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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 |
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Term
True or False
A single vaccine provides sufficient protection against all strains of IB |
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Definition
False
-no cross-protection between serotypes |
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Term
Why would a disease be classified as reportable? |
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Definition
significant importance to human/animal health, or Canadian economy |
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Term
Name 2 reportable poultry diseases |
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Definition
Fowl Typhoid Pullorum Disease Newcastle Disease Avian Influenza |
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Term
What bacteria causes Fowl Typhoid disease and what poultry does it affect? |
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Definition
Salmonella Gallinarum -clinical disease in growers/adult birds -affects chickens, turkeys & minor poultry
-high mortality |
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Term
What bacteria causes Pullorum disease and what poultry does it affect? |
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Definition
Salmonella Pullorum -clinical disease in young chicks
-high mortality |
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Term
How are Fowl Typhoid and Pullorum transmitted? How do we test for them? |
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Definition
from parent to offspring through the egg
-fluff samples collected at hatchery & tested |
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Term
What causes Newcastle Disease? Which forms are most virulent? |
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Definition
avian paramyxovirus
volegenic forms |
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Term
True or False
All forms of Newcastle Disease are reportable |
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Definition
False
volegenic forms are reportable |
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Term
What are the clinical signs of Newcastle disease? (5) |
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Definition
-hemorrhage in intestinal tract -conjunctivitis, swelling of eyelids, ocular discharge -neurological signs -hemorrhage in intestinal tract -high mortality |
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Term
True or False
Newcastle Disease has potential to be zoonotic |
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Definition
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Term
What causes Avian Influenza? What are its characteristics? |
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Definition
orthomyxovirus type A influenza virus
-respiratory & nervous signs, sudden death -swelling & hemorrhage of comb & wattles |
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Term
What are the primary reservoirs/sources of introduction of Avian Inluenza onto poultry farms? |
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Definition
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Term
How is avian influenza prevented? |
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Definition
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