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Flashcards in Porcine reproductive disease Deck (59)
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1
Q

What are the key targets in pig units?

A
2
Q

What are normal farrowing rates?

A

% of sows served that go on to successfully farrow

  • –5% Regular return (normal)*
  • –2% irregular return (normal)*
  • –<1% abortion*
  • –<1% endometritis
  • –1% NIP (not in pig. Good stockman ship should prevent this )
  • –1% cull
  • –1% death
  • –Total loss 11%
  • –Therefore 89% FR

–If you are lower than 89% normally one of the above factors is a problem

–Usually one of these*

3
Q

Most reproductive failure in the pig is due to

A

management shortcomings

4
Q

Discuss post weaning management?

A

•After weaning sow important to give boar contact (nose to nose contact) from day 1 is essential.

–LH pulsatility

–Must stop day before service

  • This should be intensive, for a short time, twice a day.
  • Best if sows are brought to the boar.
  • Apply back-pressure test (if you put pressure on and she stays standing still she is ready to serve)
  • Continuous contact is NOT desirable, habituation
  • Sows need to be on ad-lib lactator if they want optimal results to make sure egg quality is high
5
Q

Discuss post weaning management further?

A

•Day length is important:

–16 hours of light

–200 Lux (needs high percentage of blue light)

–Important is like this 365 days a year

  • Wean-to-Service Interval is usually 5 days. Commonest day for weaning is a Thursday with serving on following monday
  • Sows should be served 24 hours after onset of standing heat.

–Gilts 8-12hrs

6
Q

Discuss post weaning management with regards to insemination?

A

•Min two inseminations

–24hr intervals (Sows)

–12hr intervals (Gilts)

–Big herds

  • Sows will usually need to be moved either <5 days after insemination, OR not until 35 days after insemination (otherwise will interfere with implantation)
  • Between 5-35 days the eggs get little hooks on the side and when they go into uterus they hook onto uterus and if you stress her in between this period those hooks can break and she will loose pregnancy
7
Q

Compare the semens journey to the eggs journey?

A
  • Semen has a long way to travel (sows uterus is very long)
  • Survives for 48 hours in uterus
  • Capacitation takes 4-6 hours
  • Eggs are viable for much shorter time 8-12 hours
  • Therefore Semen needs to be waiting for egg this is why we put the early service in to get that semen waiting in there for the egg
  • Service timing crucial
  • Big herds
8
Q

Discuss feeding in fertility management?

A

•Feeding in lactation is important/critical:

–Excessive weight loss will result in longer W-S (weaning to standing) interval and lower numbers born in subsequent farrowing

  • Preparing the sow to be re-served occurs from the end of the previous dry period (keep her udder healthy, build her up carefully, max feed intake in 3rd week of lactation is determined by how you built her up in first 10 days)
  • 26 d average lactation
9
Q

How to BCS kids?

A

•Poor BCS is most common reason for extended W-S

–The loss during lactation more important than end result

  • Aim to only lose 0.5 during lactation
  • Most sows should be 2-2.5 at weaning
10
Q

Discuss lactation feeding?

A
  • 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
  • Key stockman task
  • Some animals will still struggle to maintain body condition
  • Density vs Volume
  • If you don’t sort this out early you end up selecting against best mothers which are the gilts who will have largest litters but their second parity will let the side down
  • Second litter drop
  • The quality of the next litter is already being determined
11
Q

What are the reproductive targets for gilts?

A
  • Puberty by 180 - 210 days of age
  • Boar contact from d180
  • Mated at 235 -255 days at 135 -150 kg live-weight (either side of this range they will have a shorter life span and less piglets per litter) line dependant
  • Mated at 2nd or 3rd recorded heat period. The 1st heat will have a low born alive.
  • None on Altresyn before already had a heat
  • Farrowing rate +4% better than sow average
  • Total born within 0.5 pig / litter of sow herd average
  • Successfully re-breed within 6 days of weaning
  • Over weight poorer longevity and more expensive to rear
  • Under weight higher risk of culling due to poor ability to perform in first lactation
12
Q

Discuss Altresyn/Regumate?

A
  • Progestagen synchronization product
  • Altresyn/Regumate
  • Dosed 5ml orally for 18 days – must be same time each day (+/- 30 mins)
  • Oestrus around 5 days later
  • Very common especially in batch farrowing systems
13
Q

Discuss autumn infertility?

A
  • Pig originally a season spring breeder
  • Typically gilts and young sows affected by autumn infertility. Manifests as:

–Not cycling

–Increased returns

–Abortions

  • Caused by short days
  • Variation in day night temperature
  • Natural in the pig
14
Q

How can you prepare for autumn infetility?

A

Be prepared for seasonal infertility

  • Increase feed level 0.25-0.5 kg/sow/day
  • Increase boar contact 30-60 min/day
  • Avoid chilling
15
Q

Discuss summer infertility?

A
  • Farmer has dug them wallows and filled with water tanker. It is an expectation in outdoor farms to prevent heat stress and sunburn.
  • Water quality needs to be maintained needs to keep a healthy mud coat on them.
  • Sunburn creates PGF2alpha which damages fertility
16
Q

It’s all hormones look at this?

A
17
Q

Is poor fertility due to infectious disease?

A
  • Sows or boars off-feed
  • Sows or boars pyrexic
  • Rarely this easy with endemic disease
  • Abortions/mummified foetuses
  • Irregular returns to heat
  • Weak and premature pigs
  • High incidence of mummies and/or stillbirths
  • Pigs not getting pregnant
  • Often just one of the above signs and can be subtle
18
Q

Name Infectious causes of porcine Reproductive Failure?

A

•Viruses are the most common infectious cause of reproductive failure in pigs.

•Most commonly:

–PRRSv

–Swine Influenza

–SMEDI

19
Q

Discuss Porcine Reproductive and Respiratory Syndrome Virus (PRRSv)?

A

•‘Blue Ear Disease’. Arrived in 1991.

–Blue ears is a sign of septicaemia in the pig and only a small amount of pigs with PRRSv will get blue ears.

  • Genotype 1 (Europe), Genotype 2 (USA more aggressive)
  • Spread by movement of carrier pigs (airborne spread initially spread around in semen from breeding studs) You can control what people, pigs and vehicles come in to farm to best protect.
  • Invades and kills macrophages.
20
Q

What are the 3 disease statuses of PRRSv?

A

Negative

–Biosecurity is key

–Check status maintained with serology

Positive, stable

–Sows serologically positive but not shedding virus/viraemic

–Piglets can be weaned virus –ve

–Achieved primarily with vaccination

Positive, unstable

–Sows serologically positive and shedding virus

–Piglets weaned virus +ve – problems in feeding herd

–Restabilisation can be difficult to achieve

21
Q
A
22
Q

Discuss PRRSv control?

A

Negative - risks

–Stock

–People

–Vehicles

–Airbourne

23
Q

What is the PRRSv Replacement strategy?

A

PRRS –ve:

–Buy –ve replacements

–Quarantine min 8wks and check with own sentinels after 5wks

–Strict biosecurity

–Home breed

PRRS +ve

–Isolate and vaccinate replacements

–Vaccination

–Do not serve gilts until >6wks since infection/vaccination

24
Q

Discuss other methods of PRRSv control?

A
  • Monitoring the positive herd
  • PCR - Oral fluids, bloods, tissue
  • Oral Fluid

–Sample lots of animals easily (should be)

–Rarely enough virus to sequence

–Contamination

•Bloods

–Ear pin prick in 30x piglets at weaning

–Aborted sows

–Can re live vaccine

–Sequencing

•Tissue

–Foetal thymus

–Spleen

–Lung

25
Q

Discuss swine influenza?

A
  • Predominantly a respiratory disease but will cause sows to return by causing pyrexia
  • Therefore it is usually included in the investigation of high pregnancy failure rates
  • H1N1, H1N2 and H3N2 most common
  • Can be introduced by infected people, carrier pigs, birds.
  • Can also cause inappetance in farrowing house and disease in pre-weaned piglets
  • Diagnosis: clinical signs, nasal swabs, serology
  • Control: Biosecurity
26
Q

What is SMEDI?

A

Stillbirth

Mummification

Embryonic Death

Infertility

Syndrome various viral cause: parvo being the main one. Spreading of virus result in sequential fetal death. Most sows are vaccinated for parvo now

27
Q
A
28
Q

Discuss SMEDI further?

A

•Is a syndrome with various (usually ubiquitous viral) causes:

–Parvovirus (PPV)

–Teschoviruses (Sapelovirus, Teschen/ Talfan)

–Encephalomyocarditis Virus (EMCV)

–PCV2

  • Transplacental infection of fetuses occurs resulting in sequential fetal death.
  • Abortion is rare; fetuses usually go to term as no prostaglandin trigger
29
Q

Discuss Porcine Parvovirus (PPV)?

A
  • Common and important
  • Survives well outside of pig – ubiquitous
  • Sows develop life-long immunity so clinical disease usually seen in gilts
  • Generally no clinical signs unless pregnant when exposed
  • If infected <35d gestation

–Return to service

•If infected 35-70 days gestation

–Sequential death of piglets and mummification

–Variable sized mummies

•If infected 70+days

–Some weak piglets/stillbirths

•Diagnosis: fetal serology and PCR

30
Q

Discuss Porcine Parvovirus (PPV)
- Control

A
  • Now rare due to very effective vaccines
  • Historically one dose given to gilts combined with Erysipelas
  • Relied on environmental boosting
  • 2015 blood sampling found variable serological evidence of exposure
  • Now common to vaccinate every parity/every other parity on my herds
  • Ery Parvo 4x cost of Ery
31
Q

What is Teschoviruses?

A
  • Formerly Enteroviruses
  • Serotypes 1,3,6 and 8 cause repro dz
  • Faeco-oral transmission
  • Usually seen in gilts or naïve animals
  • SMEDI presentation
  • Diagnosis: serology and virus isolation
  • Control: Controlled Exposure to faeces to immunise gilts/ sows at least 6wks prior to breeding.
32
Q

Discuss Encephalomyocarditis Virus (EMCV)?

A
  • Main reservoir is rats.
  • Type A causes reproductive disease
  • Type B causes heart failure.
  • Clinical disease tends to occur when high prevalence of rats.
  • SMEDI signs
  • Diagnosis: Serology/virus isolation
  • Control: check source of incoming breeding stock for pathogenic strains
33
Q

Discuss Porcine Circovirus 2 (PCV2)?

A
  • No negative sources
  • Causes heart muscle damage in developing foetus.
  • SMEDI signs
  • Often seen in naïve gilts.

•Diagnosis: Fetal Myocarditis & Immunohistochemistry

  • Control: Vaccination of gilts pre-breeding is very good at preventing it. Gilts vaccinated at PCV2 at growing place then given a booster and breeding facility.
  • Causes a globally important disease of weaned piglets
34
Q

Discuss Aujezsky’s disease (AD)?

A
  • Aka: Pseudorabies virus
  • Herpes virus so can be carried
  • Usually no clinical signs in the sow
  • Abortions seen, with neurological signs in newborn piglets
  • Signs become milder as age increases.
  • Not currently in the UK
  • Notifiable
35
Q

Discuss Classical Swine Fever?

A
  • Pestivirus similar to BVD, can cause persistent infections
  • Important cause of Congenital Tremor (CT) (type A1)which is the reason why CSF should ALWAYS cross your mind when encountering these.
  • Clinical signs vary and abortion may occur at any stage and will be a first sign in an incursion.
  • 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
  • Not currently in the UK
36
Q

Discuss African Swine Fever?

A
  • Deoxivirus
  • Main clinical signs:

–Pyrexia, anorexia, lethargy, sudden death

–Also causes abortions, stillbirths and weak litters

  • Very similar clinically to CSF
  • Never been a case in UK causing huge problems in Russia and eastern europe.
  • Lives for a long time in cooked and cured meat.
37
Q

What are the Bacterial causes of porcine reproductive failure?

A
  • Leptospirosis diff to diagnose
  • Erysipelas
  • Brucella suis
  • Of dubious significance:

–Chlamydophila

–Toxolasma gondii

38
Q

Discuss Leptospirosis?

A
  • Main serovars causing disease in pig are L. pomona, L. tarassovi and L. bratislava/muenchen.
  • Clinical signs: abortions/stillbirths, vaginal discharge

•Diagnosis: Difficult (chronic). Serology in returning sows. Foetal tissues (FAT).

•Treatment: Antimicrobials (tetracyclines)

•Control: use of AI, hygiene in service areas, vaccination, rodent control

•Risk: dirty farms get it

39
Q

Discuss Erysipelas?

A
  • E. rhusiopathiae – ubiquitous
  • Excreted via saliva, faeces or urine
  • Zoonotic potential (rare)
  • Abortions, mummified foetuses, returns to service
  • Diagnosis: difficult, diamond lesions on skin
  • Tx: sensitive to penicillin
  • Control: Vaccination
  • Nearly all commercial herds vaccinating
40
Q

Discuss Brucella suis?

A
  • Not in UK
  • Carried by the European hare but never been found in this species in UK (they are tested)
  • Causes infertility, abortion and weak piglets, can also cause abscesses
  • FSC always cultured at APHA
  • Serological cross reactions with Yersinia enterocolitica can be problematic
41
Q

Discuss Endometritis & vulval discharge syndrome?

A
  • Discharge at 14-21d post-service
  • Discharge is ‘Normal’ up to 2 days post-service
  • Many different bacteria (opportunists)
  • May cause reduced fertility
  • Lots of risk factors related to management at service

•Diagnosis: observation and records

•Control: cull affected sows, service management

  • Very uncommon in modern production
  • All hygiene causes
42
Q

What are the Notifiable diseases causing porcine reproductive failure?

A
  • Brucella suis
  • Aujezsky’s disease
  • Classical Swine Fever
  • African Swine Fever
43
Q

Recap what has gone so far?

A
  • Most reproductive failures due to management deficiencies
  • Sick pigs (in real world a poor indicator), SMEDI, weak piglets, irregular returns = more likely to be infectious
  • Viruses most common infectious cause
  • Most common causes controlled with vaccination – destabilisation common with some diseases
44
Q

How should you approach a repro problem in pigs?

A
  • Can be challenging!
  • Be methodical:

–Data

–Define area of failure

–Identify ‘problem’

–Further investigations

–Identify cause

–Remedial action

–Monitor

45
Q

What data do you need to assess reproduction?

A

Individual level:

–Sow no. parity, dates of mating/farrowing/service

–No. and type of services at each mating

–Semen/boars used

–No. of piglets born/litter (dead/alive)

–Weaning to service interval

Herd level:

–Litter size variation, service intervals, abortions, females not in-pig, discharges, parity distribution

46
Q

What else should you consider about fertility problems?

A

Define area of problem

  1. Anoestrus
  2. Ovulation and oocyte production
  3. Fertilisation
  4. Implantation
  5. Foetal death and abortion
  6. Stillbirths
47
Q

Look at this picture showing correlation between embryo and foetal death and the consequences?

A

Picture shows the failure of fertility and what the result of this failure would be depending on the stage of failure.

48
Q

Discuss signs of and causes of anoestrus/not coming on heat in the sow?

A

1. Anoestrus

  • Rarely true Anoestrus usually increased W-S (weaning -service) interval
  • Usually related to sub-optimal nutrition during lactation in young animals.
  • Rarely failure to recognise oestrus (rule out)
  • Main areas:

Gilts: group management, health & nutrition, acclimatisation, boar contact, light, housing

Sows: nutrition, environmental management

49
Q

Discuss signs of and causes of poor ovulation in the sow?

A
  • Low/variable litter size, decreased farrowing rate
  • Eggs have been produced by haven’t be ovulated?Main areas of problems:
  • –Nutrition
  • –Hybrid vigour
  • –Good general health
  • –Ensure good feed intake during lactation
  • –Manage sows so they come into oestrus during the early fertile period (4-6d)
  • –Disease causing early embryonic death or foetal damage later on
50
Q

Discuss signs of and causes of poor fertilisation in the sow?

A
  • High rate of returns to service/variable litter size.
  • Main areas:

–Accurate oestrus detection

–Served at correct time

–Nutrition

–Care with group changes after service

–Boar management if natural service – very rare

–Disease

  • Semen storage
51
Q

Discuss implantation and signs of and causes of poor/failure of implantation in the sow?

A
  • Iplantation occurs d14-17 after ovulation
  • Irregular returns (d25-35), small litter sizes.
  • Main areas:

–Nutrition

–Boar contact for >28d post-service

–16hrs light

–Stress 2-25d post-service

–General sow health

52
Q

Discuss foetal death/abortion in the sow?

A

•If embryos die <35d

–Resorption, return to service ~63d

•If embryos present after 35d

–Mummification

  • Crown rump length will indicate age at death
  • If large no. of piglets healthy then unlikely to be disease
  • If small no. of pigs born healthy and large no. mummified then disease more likely
53
Q

Discuss stillbirths in the sow?

A

•Key thing to ask were they fresh or mummified. If fresh it is managment factor and those pigs have died during partruition.

  • Very frustrating to investigate.

•Usually related to sow factors:

–Fat sows, prolonged farrowing/dystocia

–Large litters, large piglets

–Fresh born dead is usually poor supervision around farrowing

•Usually not infectious

54
Q

Outline a breeding herd vaccination schedule?

A

Suiseng: colostrum boosting vacine

55
Q

Outline stages of reproductive cycle associated with infertility?

A
56
Q

Look at this table for differentiating between infectious and non-infectious causes of reproductive failure?

A
57
Q

If you suspect infectious causes which samples should you take?

A

If sows are systemically ill:

  • Serum (paired), nasal swabs, other tissues as appropriate
  • Fetuses/fetal tissues often unrewarding

If sows are clinically ‘well’:

  • Fetuses/fetal tissues, placenta
  • Serology from sow may be helpful to rule out disease (seroconverted)
  • Foetus usually better than sow samples due to vaccine complications
  • However be prepared to be frustrated

Try to submit samples from 4-6 fetuses/litter from at least 3 litters. (Brain, Heart, Lung, Liver, Spleen, Kidney, Placenta, FSC, FF)

58
Q

Summarise reproductive failure?

A
  • Most reproductive failures due to management deficiencies
  • Sick pigs, SMEDI, weak piglets = more likely to be infectious
  • Viruses most common infectious cause
  • Veterinary investigation can be challenging
  • Use data to indentify ‘problem’ area
  • May be infectious and non-infectious factors affecting reproductive performance
59
Q

If more than what % still born warrants investigation/intervention?

A

7%

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