Unit 3 - Swine intro to PMWS Flashcards
Define suckler.
A pig that is still nursing. Age range depends upon age at weaning in a given
management system
Define weaner.
A pig that has recently been weaned.
Define nursery pig.
A pig that has been weaned but has not reached the grow-finish stage. These pigs
may weigh 18 to 70 pounds or so depending on the type of facilities.
Define feeder pig.
A pig that is destined to be fed out and slaughtered. The term usually refers to a
young pig that is ready to enter the grow-finish stage.
Define grower.
A pig that is in the 40 to 170 pound range or so (see definition of nursery pig).
Define finisher.
Term that is used many times to refer to a pig in the grow-finish stage. They can
range from 40 to 290 lbs.
Define market hog.
One that is ready for slaughter. Most slaughter hogs in this country weigh about 240 to 290 pounds. Individual meat packers have different ideal weights.
Define gilt.
A female pig.
If the gilt is retained in the herd for breeding purposes, she is
referred to as a gilt until after she farrows and some refer to her as a gilt until after her first litter is weaned. Then she becomes a sow
Define barrow.
A castrated male pig. Essentially all male pigs not used for breeding purposes arecastrated.
What is a continuous flow operation?
An operation that may put pigs into barns where the pigs are continually added to existing grower-finisher swine.
Slowest growing pigs are often left behind
What is an all-in all-out operation?
All pigs in a room, building, site, or location are moved out before the next group of younger pigs is moved in.
Are continuous flow or all-in all-out operations more likely to have infectious diseases?
continuous
True specific pathogen free swine (SPF) are ________ derived while others are kept as SPF simply by being born from true SPF (sows/boars).
Caesarian
sows
What are SPF swine used for?
The establishment of disease free breeding stock and the preservation of valuable bloodlines that were infected with pathogens that couldn’t be eliminated by other means
What are the limitations associated with maintaining SPF swine?
Very labor intensive and expensive
Young pigs require more attention and can be difficult to rear
It isn’t a perfect system - what if they are exposed to disease agents? carry undetected pathogens? diseases are transmitted in utero?
What are isowean (MEW, modified MEW, SEW) pigs?
Early weaned pigs to get them away from the sows before infectious agents are transmitted
What are ioswean pig protocols tailored to do?
Get rid of or control specific disease problems
What key issues are associated with isowean pig protocols?
Sows should not be going through an active infection during or shortly after farrowing
Immunize, expose, etc, at least 3-4 weeks before farrowing
Strict biosecurity must be maintained after weaning
What are the 2 different sites for two-site treating operations?
Site 1: Sow herd and neonates
Site 2: Separate, isolated facility for weaners-growers- finishers
When do piglets have the highest levels of immunoglobulin from colostrum? Baseline?
Highest - 1-2 days of age
Baseline - 3-4 weeks of age
When do piglets immunoglobulin levels from active immune responses start to increase? At the level of a normal ‘adult’?
Increase - 3 weeks of age
Normal ‘adult’ - 6-8 weeks
Infections of PRRS virus can persist for _____+ days.
157
Where is PRRS carried?
lymphoid
In what tissues is PRRS present?
oropharynx, milk, feces, semen, urine, and other tissues
During what time of year is ‘PRRS season’ in the midwest?
October/early November
T/F: PRRS is relatively resistant to all disinfectants.
False - it is readily inactivated by disinfectants
What is a major factor in the epidemiology and transmission of PRRS?
Persistence in the host
T/F: PRRS infection can go through a herd quickly or slowly
true
T/F: PRRS shedding can be intermittent.
True
It is believed that PRRS remains in the herd at least ___ months following the cessation of clinical signs.
6
What is the major mode of PRRS transmission? Other modes?
Major - direct contact from pig to pig
Others - fomites, in-utero transmission, semen from acutely infected boars
What clinical signs are associated with PRRS in pigs?
Interstitial pneumonia with a ‘thumping’ type of respiration
Mouth breathing, nasal discharge, sneezing
Listlessness, lateral recumbency, CNS-signs, and paddling
Vomiting
What lesions are associated with PRRS (non-respiratory)?
Palpebral edema
Edema elsewhere in the body
Enlarged lymph nodes
What is the pathogenesis of PRRS?
PRRS virus attacks pulmonary alveolar macrophages (PAM) and circulating macrophages
Apoptosis of infected PAM and adjacent (bystander cell apoptosis)
Pre-weaning mortality due to PRRS may be ___-___ percent especially in weakborn pigs that can die of _____ and _______.
50-60%
Starvation and crushing
Secondary infections in PRRS infected pigs are common with what agents?
S. suis, respiratory, and enteric pathogens
In chronically infected PRRS herds, the clinical disease often occurs __-___ days following weaning,
10-14 days
What clinical signs are associated with PRRS in sows?
Transient fever (104-106F) Anorexia Listlessness that may last 4-7 days If nursing: agalactia or hypogalactia Reproductive failure
What reproductive failure is associated with PRRS in sows?
Small and weak live born pigs Premature farrowing (5-7 days) Increased late term abortions Autolyzed and edematous stillbirths that are tan-brown Occasional mummies Poor conception rate during recovery
What is the standard diagnostic test for PRRS? Other options?
Standard - ELISA
Others - IFA, immunohistochemistry, RT-PCR, virus isolation, histopath, and saliva testing
What is PRRS RT-PCR performed on (sample)?
Serum, tissues, and boar semen
What is the sample of choice for saliva testing for PRRS and what does the test detect?
Saliva is collected from cotton ropes - piggies chew on them
Tested for the presence of antibody or the virus itself
What are the options for PRRSV herd eradication?
Depop-repop Depop-repop by site Rollover Modified rollover SEW
What are the requirements for depop-repop for PRRS herd eradication?
Replacements must be negative
Biosecurity must be maintained
How is site depop-repop for PRRS herd eradication done?
Two or more breeding sites are needed
Vacate at least one site for clean replacement gilts
Move all infected sows to other sites
How is rollover for PRRS herd eradication done?
The herd is closed for 200 days
PRRSV-negative replacements are used if indicated
How is modified rollover for PRRS herd eradication done?
Make sure all breeding animals are vaccinated or infected
The herd is closed for 200 days
PRRSV-negative replacements are used if indicated
What are the requirements for SEW for PRRS herd eradication?
No active infections in the breeding herd
Piglets should be negative
How is PRRSv prevented?
Buy from reputable sources that have naive animals
Good biosecurity
Vaccination with MLV (infected herds only) or natural exposure
Exposure for replacements in infected herds by serum inoculation from acutely infected animals
What causes Porcine circovirus-associated diseases (PCVAD)?
PCV2 or PCV3
What disease/lesions has PCV3 been recently indicated in causing?
Fetal deaths, myocarditis, and vasculitis of the heart and spleen
PCVAD most often affects what population of pigs?
Pigs between 12-16 weeks of age
More commonly around the early grow-finish stage
Where is the PCVAD virus excreted?
In the feces, urine, and nasal secretions from pigs in the ACUTE stages of infection
PCVAD progresses randomly through a hog facility for ___-___ weeks before resolving.
3-5 weeks
What clinical signs are associated with PCVAD?
Initial high fever with listlessness Dyspnea Light coughing \+/- diarrhea Markedly enlarged lymph nodes \+/- Jaundice Rough hair coat Emaciation Death Reproduction failure
What syndrome occurs in 1-10% of PCVAD cases that has a high mortality rate and is characterized by skin lesions, neurological deterioration, and kidney failure.
Porcine dermatitis and nephropathy syndrome
What gross lesions are associated with PCVAD?
Enlarged lymph nodes (inguinal, mesenteric, bronchial, mediastinal) with a white homogenous appearance on cut surface
Lungs - Firm, non-collapsed, rubbery, and mottled with grey nodules +/- patchy interstitial pneumonia
Liver- atrophied and mottled with yellow-orange areas
Kidneys - no lesions or enlarged, waxy, and diffuse white foci
What histopathic lesions are associated with PCVAD?
Lymph nodes - loss of B-cell follicles, infiltration of t-cell areas by histiocytic cells, and vasculitis
What PCVAD diagnostic test can be used to differentiate between PCV2 and PCV3?
Multiplex quantitative PCR
What is the standard PCVAD diagnostic test at ISU?
Immunohistochemistry
Why is serology not useful in diagnosing PCVAD?
> 80% of all pigs tested will be positive
How is PCVAD treated?
No treatment - supportive care
How is PCVAD prevented?
Vaccination
Good management - all-in/all-out, good sanitation, good air-quality, and good nutrition
Isolate PCVAD-suspect pigs from the rest of the group
Allow replacement gilts to generate immunityq
What is the vaccination protocol for PCVAD?
Immunize pigs at 3 and 5 weeks of age
Immunize replacement gilts
Immunize sows pre-breeding
