Conditions or ailments that are the cause of a problem that you see - your observation.

Your vet may diagnose

Vulvar Seal Inadequate

Synonyms: Pneumovagina, Wind-Sucking


During pregnancy, the mare's uterus is protected from bacterial contamination by 2 barriers. The deeper barrier is a closed, healthy cervix. The external barrier is a tight seal between the two vulvar lips. This prevents air and debris from traveling forward into the vagina, and this is important for health of the uterus and for maintenance of pregnancy. A mare with poor vulvar seal may aspirate air into the vagina, sometimes causing an audible sound during exercise, i.e. "windsucking".

Mares can have a poor vulvar seal for several reasons. First, genetics plays a role. Mares with poor vulvar conformation tend to have a poor seal. A vulva that tilts forward toward the anus tend to encourage contamination of the deeper parts of the tract.

Traumatic injuries to the vulva from any cause may compromise the vulvar seal. Mares that have had many Caslick's operations may have a poor vulvar seal. The Caslick's procedure involves cutting and removing tissue from the vulva, and then suturing it together to create a seal. When this procedure is repeated annually, over time vulvar tissue is lost and a gap develops.

DIAGNOSIS is reached with an examination and correlation of a mare's reproductive state with the ability of the vulva to act as a barrier.

TREATMENT is through the use of the Caslick's Operation, in which the upper 2/3 of the vulvar lips are sutured, and heal together to create a complete seal. In some cases, reconstructive surgery other than Caslick's may also be needed.

my vet's role


The prognosis for poor vulvar seal depends on the severity of the problem and the ability to recreate a vulvar seal surgically.

my role

Questions To Ask Your Vet:
  • Does this mare need a Caslick's procedure?
  • What can you do to reduce the likelihood that repeated Caslick's procedures will result in a poor vulvar seal?

Mares for reproductive use should have good vulvar conformation and vulvar seal. Purchase mares with good vulvar conformation and seal.

Caslick's techniques that minimize the amount of tissue removed reduce the development of long-term problems with vulvar seal.

further reading & resources

Author: Doug Thal DVM Dipl. ABVP