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Vulval discharge syndrome

Since 1985 there has been a gradual reduction in farrowing rates in many herds associated with increased repeats in sows. A survey carried out at that time indicated that up to 24% of herds may have had previously unrecognised problems with this disease.

A discharge from the vulva post-service does not automatically mean there has been a pregnancy failure, but it will in most cases indicate infection. Discharges can arise from the rectum, the vulva, the vagina, the cervix and the uterus. Discharges can also arise from infection of the kidneys (pyelonephritis) or the bladder (cystitis) with pus being passed in the urine. It is important to record the time when discharges are first seen, their colour and composition and effects on the sow.

Vulval discharges are common within 3-4 days of farrowing when a thick viscous material may be excreted. If the sow is healthy, the udder is normal and there is no mastitis, ignore it.

A heavy smelling bloody discharge may indicate a retained piglet or afterbirth.

Discharges are important between 14-21 days post-service. The lips of the vulva of each sow should be parted daily and any tackiness or small discharge noted. The sow should be marked and if she repeats a problem may be developing. Discharging sows may be pregnant and always pregnancy test before culling.

Discharges in healthy sows are normal up to 5 days post farrowing at mating and 3 - 5 days post mating - only if slight.


Piglets, Weaners & Growers
  • N/A
  • Vulval discharges are common within 3-4 days of farrowing when a thick viscous material may be excreted. This is normal.
  • If the sow is healthy, the udder is normal and there is no mastitis, ignore it. It is common practice to inject such sows, but this is not necessary under these circumstances.
  • A heavy smelling bloody discharge may be from a retained piglet or afterbirth.
  • Sow may be ill.
  • Mastitis.
  • Increases in returns at 18 - 23 days post service with discharge.
  • Increases in returns >23 days post service with discharge.
  • Increases in sows not in pig.
  • Reduced farrowing rates by 10 - 20%.
  • Increased negative or doubtful pregnancy tests at 30 days post service.
  • Litter size normal.
  • Embryo death.
  • Abortion.
  • Anoestrus.
The table below gives the times discharges might be seen and their likely significance.


Causes / contributing factors

Infection can be caused in a number of ways:

  • Vulval discharges arise from opportunist bacteria in the anterior vagina that cause a womb infection or endometritis. These include:
      - Actinomyces pyogenes
      - Chlamydia
      - E. coli *
      - A. suis
      - Erysipelothrix
      - Klebsiella *
      - Leptospira bratislava / muenchen
      - Pasteurella
      - Proteus
      - Pseudomonas
      - Staphylococci *
      - Streptococci * (* Common causes)
  • Herds with high numbers of old sows.
  • A short lactation length (14-21 days).
  • Multiple matings. Cross mating boars.
  • Handling the prepuce at mating and squeezing the preputial sac.
  • No supervision at mating.
  • Matings towards the end of the oestrus period.
  • Wet, dirty boar pens. Poor drainage. Continual use.
  • Dirty, wet sow mating pens and continual use without cleaning.
  • Small stalls where the sow adopts a dog sitting posture with heavy contamination of the vulva.
  • Housing maiden gilts in stalls.
  • Heavy vulval contamination, for example in maiden gilts housed on slats where slurry spills over.
  • Early embryo mortality.
  • Re-mating discharging sows.
  • Using old boars on young sows.
  • Using young boars on older sows.


Diagnosis is considered in three parts:

  1. Studying records.
  2. Observations on vulvas 14 - 21 days post service.
  3. Bacteriological examinations of swabs from the prepuce and vagina from all boars and 10 problem sows and post mortem examinations on the uteri of affected sows.
Cultures are carried out on the swabs and the predominating bacteria determined. Sensitivity tests identify antibiotics that could be used.

The main organisms associated with endometritis and vulval discharges are opportunist invaders. In some herds no specific organism can be identified, although bacteriological tests may show one or more bacteria predominating either in the prepuce or vagina. A precise diagnosis can be difficult.

Further Reading

Click on the links below to find out more about this disease, including treatment, management control and prevention information. The top link is the main article on this disease.