Pig International - July/August 2017 - 22

22 ❙ PigInternational
PSEUDORABIES IN PIGS

Vaccination for PRV
PRV vaccination
is a useful tool in
PRV control, but it
does not protect completely. Vaccinated
pigs are indeed less
likely to become infected, have reduced
illness and mortality
rates, and shed much less virus than
unvaccinated pigs. Emerging new
"hot" Chinese strains of PRV are often
blamed for vaccine failures, but variation in virulence has always been a
feature of PRV. New type-specific vaccines are being produced, but the old
Bartha K-61 vaccine still performs well
when there are no complicating disease
issues. All vaccines fail under heavy
virus exposure and influential complicating and immunosuppressive factors. 
Vaccination of pigs is often not
satisfyingly effective in controlling pig
to pig transfers, but the vaccination of

sows strongly inhibits sow to sow and
sow to pig transmission. Modified live
PRV vaccines generally produce better primary immunity and can be used
intranasally, while killed PRV vaccines produce better booster effects.  

is the key, regardless of the virus
strain. The advent of gene-deleted
vaccines greatly aids the process.
■ Determine herd status. Find
out what is the PRV status of
the herd and where and when in
production the infection is ocGene deletion and
curring. If gene-deleted DIVA
DIVA vaccines
vaccine is used in the piglets, one
Vaccines with deletion in the gE
can discover the age at which pigs
(gI) locus attentuate the virus and
become infected and adjust vacpermit differentiation of infected
cination and management accordand vaccinated animals by a gE
ingly. If sows are infected, piglets
ELISA test. Common deletions
will carry the maternal antibody
include gC, gE, gG and TK. DIVA
to gE (wild virus) for up to 15-16
tests for gC (gIII) and gG (gX) deleweeks of age, but the maternal
tions exist but are seldom used.
antibody is protective for only 7
to 9 weeks. Clean pigs can
be produced from infected
Learn more about how to
but vaccinated sows.
prevent PRV: Improving
■ Adjust vaccination
the pig's environment,
schedule. Typically, an inwww.WATTAgNet.com/ tramuscular MLV vaccine
articles/27130
is given at 7 to 9 weeks of
age. Earlier intramuscular
vaccination fails due to
PRV control and elimination
maternal antibody interference.  
Early PRV eradication focused on
Intranasal MLV vaccination
"stamping out" (forced depopulation)
bypasses maternal Ab, and it is
of infected herds, but it was slow
common practice in China to give
and costly and failed because there
intranasal vaccination to pigs at
were no changes in management
birth, but the immunity obtained is
practices; many depop/repop herds
limited and short-lived. Intranasal
became reinfected. In elimination
vaccination is better done at weanprograms over the past 30 years, PRV
ing, but generally is not necessary
is "walked off the farm" by invoking
unless a difficult PRV problem
good biomanagement practices. PRV
exists in the nursery. Sows should
can be eliminated by exposure conbe mass-vaccinated every 3 to 4
trol via all-in/all-out management
months. Killed vaccine does effecand timely vaccinations.  Exposure
tively booster sow immunity, but
control by all-in/all-out management
MLV vaccination of sows can sucwww.WATTAgNet.com ❙ July/August 2017

Kadmy | Dreamstime.com

Salmonellosis, enzootic pneumonia and "shaker pig disease." Several
of these diseases often occur together, particularly APP as a sequela
to PRV. PRRS and PCV2 occur
predominantly in nursery pigs, while
PRV troubles emerge in growingfinishing pigs, but PRRS/PCV2
continues into grow-finish while
PRV is occasionally seen in nursery
age pigs. Herds with chronic PRV
issues may have chronic CSF as
well. Diagnosis can be confirmed by
PCR, histopath, immunohistochemistry, virus isolation and by serology.


http://www.WATTAgNet.com/articles/27130 http://www.WATTAgNet.com/articles/27130 http://www.Dreamstime.com http://www.WATTAgNet.com

Table of Contents for the Digital Edition of Pig International - July/August 2017

Pig International - July/August 2017
Contents
Pigs and Money
Industry Happenings
World pork production to grow at a slower rate
5 ways phytogenics improve pig feed efficiency
Methionine beyond protein synthesis in growing pigs
Understanding pseudorabies in pigs leads to prevention
6 fiber insights for formulating livestock feed
Salmonella control: Do organic acids solve the problem?
How lactic fermented feed benefits pig production
How to treat iron deficiency in neonatal pigs
Products
Marketplace
Advertisers’ Index
Pig International - July/August 2017 - Pig International - July/August 2017
Pig International - July/August 2017 - Cover2
Pig International - July/August 2017 - Contents
Pig International - July/August 2017 - Pigs and Money
Pig International - July/August 2017 - Industry Happenings
Pig International - July/August 2017 - World pork production to grow at a slower rate
Pig International - July/August 2017 - 5
Pig International - July/August 2017 - 6
Pig International - July/August 2017 - 7
Pig International - July/August 2017 - 8
Pig International - July/August 2017 - 9
Pig International - July/August 2017 - 5 ways phytogenics improve pig feed efficiency
Pig International - July/August 2017 - 11
Pig International - July/August 2017 - 12
Pig International - July/August 2017 - 13
Pig International - July/August 2017 - Methionine beyond protein synthesis in growing pigs
Pig International - July/August 2017 - 15
Pig International - July/August 2017 - 16
Pig International - July/August 2017 - 17
Pig International - July/August 2017 - 18
Pig International - July/August 2017 - 19
Pig International - July/August 2017 - Understanding pseudorabies in pigs leads to prevention
Pig International - July/August 2017 - 21
Pig International - July/August 2017 - 22
Pig International - July/August 2017 - 23
Pig International - July/August 2017 - 6 fiber insights for formulating livestock feed
Pig International - July/August 2017 - 25
Pig International - July/August 2017 - Salmonella control: Do organic acids solve the problem?
Pig International - July/August 2017 - 27
Pig International - July/August 2017 - 28
Pig International - July/August 2017 - 29
Pig International - July/August 2017 - How lactic fermented feed benefits pig production
Pig International - July/August 2017 - 31
Pig International - July/August 2017 - 32
Pig International - July/August 2017 - 33
Pig International - July/August 2017 - How to treat iron deficiency in neonatal pigs
Pig International - July/August 2017 - 35
Pig International - July/August 2017 - 36
Pig International - July/August 2017 - 37
Pig International - July/August 2017 - Products
Pig International - July/August 2017 - 39
Pig International - July/August 2017 - Advertisers’ Index
Pig International - July/August 2017 - Cover3
Pig International - July/August 2017 - Cover4
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