Porcine clinical reproduction disease Flashcards
What is the farrowing index in pigs and what generally is the target for this
number of farrows per year average
2.35
What is farrowing rate
% of sows served that go on to successfully farrow
what is the target farrowing rate
89%
what are most reproductive failure in the pig due to
management shortcomings
Describe post weaning mangament of the sow
From point of weaning they need boar contact - should be intensive for a short time
must stop boar contact day before service
describe heat detection in pigs
back-pressure test
during postweaning phase what are sows fed
on ad-lib lactator diet
During the post-weaning period how much light do pigs need
16hrs - hard to do outdoors
what weaning-service interval are we aiming for in pigs
5 days
when should sows be served
Sows should be served 24 hours after onset of standing heat.- 2 inseminations
Gilts 8-12hrs
after service describe when pigs can be moved
Sows will usually need to be moved either <5 days after insemination, OR not until 35 days after insemination (otherwise will interfere with implantation)
when does preparing sows to be re-served start
from the end of the previous dry period
What effects does excessive weight loss during lactation result in
longer W-S interval and lower numbers born in subsequent farrowing
how much BCS is aimed to be lost during lactation in sows
0.5
should be 2.5-3 at weaning
when are piglet birth weights determined
wean to service interval and in the last 3 weeks of gestation
why is sow feed reduced on entry to farrowing accommodation
to stop her from becoming anorexic- which will affect the quality of the next litter is already being determined
describe lactation feeding in sows
Feed increased for last 3 weeks of gestation
Feed reduced on entry to farrowing accommodation
Sows carefully increased over first 7-10 days of lactation up to maximum feed intake
Some animals will still struggle to maintain BCS
what is second litter drop
When a sow is in poor condition at weaning/serving leading to a smaller next litter
when do want to successfully re-breed Gilts
within 6 days of weaning- due to them leaving more BCS
what pigs are generally affected by autumn infertility
gilts and young sows
what is autumn infertility
because they originally a season spring breeder- so in aumtumn can get pigs not cycling, increased returns and abortions
List 3 ways to reduce autumn infertility
increase feed level
increase boar contact
avoid chilling of the pig
what causes autumn infertility
short days
variation in day night temperature
natural in the pig
what is summer infertility in pigs
can occur indoor as buildings meant for colder weather
heat stress and sunburn
How to prevent sunburn in pigs
dig wallows with water source for the pigs to bathe in
How can we tell if poor fertility due to infectious disease in sows
Sows or boars off-feed
Sows or boars pyrexic
Abortions/mummified foetuses
Irregular returns to heat
Weak and premature pigs
High incidence of mummies and/or stillbirths
Often just one of the above signs and can be subtle
Rarely this easy with endemic disease
What are the most common viruses that cause pig reproductive failure
PRRSv
Swine Influenza
SMEDI
what is PRRSv
Porcine Reproductive and Respiratory Syndrome Virus
How is PRRSv spread
by movement of carrier pigs (airborne spread)
invades andkills macrophages
How does PRRSv cause disease
It invades and kills macrophages- is an immunosuppresive virus
If PRRSv is restabled on a farm what do we see
Always see disease in piglets
Don’t always see disease reproductively in the sows
what are the 3 disease statuses of PRRSv
negative
positive stable- achieved primarily with vaccination- can become unstable through genetic mutation of virus
positive unstable- restabilistion can be difficult
List 4 risks to PRRSv negative herds
Stock
people
vehicles
airborne
Describe a replacement strategy for a PRRSv negative herd
Buy –ve replacements
Quarantine min 8wks and check with own sentinels after 5wks- mix own old pigs in with them at a point
Strict biosecurity
Home breed
Describe how to monitor a postivie pig herd for PRRSv
PCR- oral fluids, bloods, tissue
How can swine influenza be introduced to a herd
infected people
carrier pigs
birds
What does swine influenza cause
mostly resp disease but will cause sows to return by causing pyrexia
Can also cause inappetence in farrowing house and disease in pre-weaned piglets
describe how to diagnose swine influenza
clinical signs
nasal swabs
serology
describe how to control swine influenza
biosecurity
staff flu jabs
what is SMEDI
Stillbirth
Mummification
Embryonic Death
Infertility
Is a syndrome with various (usually ubiquitous viral) causes: e.g. Parvovirus (PPV) and others
what is the mechanism behind SMEDI
Transplacental infection of fetuses occurs resulting in sequential fetal death.
abortion is rare
fetuses usually go to term as no PGF2a trigger
when do clinical signs of porcine parvovirus show
no clinical signs unless pregnant when exposed
then depends where in gestation they are
what would be see if pig infected with PPV <35 days gestation
Return to service
Describe how to control PPV
vaccination
what is important ot remeber about Aujezsky’s disease
notifiable
what are the clinical signs of Aujezsky’s disease
Usually no clinical signs in the sow
Abortions seen, with neurological signs in newborn piglets
Signs become milder as age increases.
How is classical swine fever spread
Spread by pigs eating infectious meat or meat products, contact with infected pigs or their faeces or body fluids, contact from infected sows to their piglets
what are the signs of classical swine fever
Important cause of Congenital Tremor (CT)
Clinical signs vary and abortion may occur at any stage and will be a first sign in an incursion
what are the main clinical signs of african swine fever
Pyrexia, anorexia, lethargy, sudden death
Also causes abortions, stillbirths and weak litters
what are the most important bacterial causes of reproductive failure in pigs
Leptospirosis
Erysipelas
Brucella suis
List the clinical signs of leptospirosis in pigs
abortions/stillbirths
vaginal discharge
Describe how to diagnose leptospirosis in pigs
Difficult (chronic)
Serology in returning sows
Foetal tissues (FAT).
Describe how to treat leptospirosis in pigs
tetracyclines
Describe how to control leptospirosis in pigs
use of AI
hygiene in service areas
vaccination
rodent control
How is Erysipelas spread
via saliva, faeces or urine
Describe the signs seen with Erysipelas
abortions, mummified fetuses, returns to service
diamond lesions on skin
Can get heart valve abscesses
describe how to treat Erysipelas
penicillin
describe how to control Erysipelas
vaccination- is very cheap vaccine
What does Brucella suis cause
Causes infertility, abortion and weak piglets, can also cause abscesses
Describe Endometritis & vulval discharge syndrome
occurs After serving
Discharge at 14-21d post-service
caused by dirty AIing
may cause reduced fertility
List 4 Notifiable diseases causing porcine reproductive failure
Brucella suis
Aujezsky’s disease
Classical Swine Fever
African Swine Fever
List 2 commonly used figures to monitor reproduction on pig units
Pigs per sow per year and weaned per sow
Why is continuous contact of a sow with a boar not desirable
can see habituation
What is the average lacatation length for a sow
26 days
When are pigs generally culled
after 5th or 6th litter
When does puberty occur in gilts
180-210 days
boar contact from 180 days of age to stimulate this
what age are gilts mated
235-55 days at 135-150kg live weight
second or third recorded heat
What is commonly used to synchronise sows
Altrenogest (progesterone)
Oestrus signs in gilts
enlargement and pinking of vulva
How can sunburn in the pig lead to reproductive problems
Can lead to production of PGF2a
Why is genetic mutation of PRRSv frequent
It is a single strand RNA virus
What causes PRRSv destabilisation in a pig unit
Genetic mutation frequent
Leads to new strains emerging on farm regularly
Leads to destabilisation
What are the 3 PRRSv disease statuses
Negative (highly risky, will see extreme acute disease if naive animals exposed)
Positive, stable (Most herds sit here, no viraemic circulation)
Positive, unstable (Pigs have viraemia and virus is circulating)
Can a farm be PRRSv negative and vaccinated
No, as the vaccine is live attenuated
Describe how herds reamin PRRSv negative
Biosecurity is key
Check status maintained with serology
What are the key points of being PRRSv positive but stable
Sows serologically positive but not shedding virus
Piglets weaned virus -ve
Acheived primarily with vaccination (every 12 weeks)
What are the key points of being PRRSv positive but unstable
sows serologically positive and shedding virus
Piglets weaned virus +ve, problems in feeding herd
restabilisation can be difficult
Describe a replacement strategy for a PRRSv positive herd
Isolate and vaccinate replacements
Vaccination
Do not serve gilts until >6 weeks since infection / vaccination
Where is porcine parvovirus found
ubiquitous, survives well outside the pig
Do animals develop immunity to porcine parvovirus
sows develop lifeling immunity so clinical disease usually seen in gilts
Likely signs if animal affected by porcine parvovirus 35-70 days into gestation?
Sequential death of piglets and mummification
Variable sized mummies
Likely signs if animal affected by porcine parvovirus 70+ days into gestation?
Some weak piglets/ stillbirths
Describe how to diagnose porcine parvovirus
fetal serology and PCR
Is Aujezsky’s disease in the UK
not currently in the UK
What is classical swine fever
Pestivirus similar to BVD,
Can cause persistent infections
Is classical swine fever in the UK
not currently
what type of virus is african swine fever
Deoxivirus
Is african swine fever in the UK
No
Is Brucella suis in the UK
No
How do we control endometritis and vulval discharge syndrome in sows
cull affected animals
service management
List 5 examples of individual level data on a pig unit
Sow parity, dates of mating/farrowing/service,
Number and types of services at each mating,
Semen/boars used,
Number of piglets born/litter,
Weaning to service interval
List 6 examples of herd level data on a pig unit
Litter size variation,
Service intervals,
Abortions,
Females not in-pig,
Discharges,
Parity distribution
List 6 areas of reproductive cycle in pigs where a problem can occur
anoestrus
ovulation and oocyte production
fertilisation
implantation
foetal death and abortion
stillbirths
Describe anoestrus in pigs
rarely true anoestrus, usually increased wean to service interval
usually sub-optimal nutrition during lactation in young animals
List 6 ways to ensure good ovulation in pigs
nutrition
hybrid vigour
good general health
ensure good feed intake during lactation
manage sows so they come into oestrus during early fertile period
disease causing early embryonic death or fetal damage managed
List 6 ways to ensure fertilisation is good on a pig unit
accurate oestrus detection
served at correct time
nutrition
care with group changes after service
boar management if natural service
disease managed
when does implantation occur in the pig
days 14-17 after ovulation
List 5 areas of management affecting implantation in pigs
nutriton
boar contact for >28 days post-service
16hr light
stress 2-25 days post service
general sow health
If pig embryos die <35 days post service
resorption and return to service -63 days
how can we estimate age at death of a aborted fetus
crown rump length will indicate age at death
Still births are usually sow related factors such as…
Fat sows = prolonged farrowing/dystocia,
Large litters, large piglets,
Fresh born dead is usually poor supervision around farrowing
Which samples for infectious disease to take if sows are systemically ill
serum
nasal swabs
Foetuses and foetal tissue often unrewarding
Which samples for infectious disease to take if sows are clinically well
Foetuses/foetal tissue/placenta,
Serology from sow,
