NADIS disease bulletins are written specifically for farmers, to increase awareness of prevalent conditions and promote disease prevention and control, in order to benefit animal health and welfare.

Farmers are advised to discuss their individual farm circumstances with their veterinary surgeon.

The Management of Vaginal Prolapse in Ewes

Few sheep farmers can claim not to have experienced some cases of vaginal prolapse in ewes. An incidence of about 1% is commonplace, but in some flocks more than 2% of ewes of all ages may be affected.

Clinical signs

Prolapse of the vagina generally occurs during the last four weeks of pregnancy. The extent of prolapse varies from eversion of the vaginal wall, visible when the ewe is lying down, to total eversion of the vagina and cervix. The prolapsed tissue rapidly becomes inflamed, swollen, traumatised and secondarily infected. The bladder usually becomes obstructed, leading to urinary retention and uraemia. If uncorrected, infection and necrosis of the prolapsed organ lead to eventual death. Additional problems resulting from persistent straining include rectal prolapse or tearing of the vaginal wall, with herniation of the intestines through the vulva. Vaginal prolapse can also lead to lambing problems.

Prevention

The causes of vaginal prolapse are far from understood, so it is difficult to offer sound advice about prevention of the problem. Most cases occur in ewes with multiple foetuses. There are plenty of anecdotal reports to suggest that bulky feed, lack of exercise, housing, excessive body condition, or allowing animals to rest on steep slopes may induce vaginal prolapse, but there are no sound data to support any of these theories. Unless affected animals are marked and culled at weaning, about 40% of vaginal prolapses recur in subsequent pregnancies.

Management

Uncomplicated cases where there is only slight eversion of the vaginal wall can often be managed using plastic bearing retainers or harnesses. However, most cases respond best to surgical correction involving suturing of the vulva -

1. Provide satisfactory pain relief: Correction of vaginal prolapses and retention using sutures around the vulva is painful and ideally should be performed with effective analgesia. Most vets use epidural analgesia to control pain and reduce straining as the prolapse is being replaced and for about 36 hours afterwards. There are some data to show enhanced ewe survival following this procedure. Unfortunately only vets are legally allowed to administer epidural injections to sheep. Foot-and-mouth movement restrictions currently prevent animals from being taken to a veterinary practice for treatment and many producers will be reluctant to request veterinary visits because of fears about disease spread. As an alternative, infiltration of local anaesthetic around the vulva may provide adequate analgesia to enable stitches to be placed, but does not prevent further straining.

2. Clean the prolapsed tissue: It is important not to use strong disinfectants which may cause irritation and lead to further straining. In many cases, dirt and faecal material may be ingrained in the vaginal mucosa and a compromise must be reached between adequate cleaning and causing further trauma.

3. Replace the prolapse carefully and completely: Gentle consistent pressure is applied with the palm of the hand or clenched fist, firstly around the perimeter of the prolapse and then at the cervix. This is not always easy, especially if there is involvement of the bladder or urethra. Preferably the ewe should be standing, but sometimes it is necessary to place the ewe on her back and raise the hind limbs. Once the prolapse is replaced, the ewe should be allowed to urinate.

4. Suture the vulval lips to prevent recurrence: Suture material should be clean and soaked in dilute disinfectant before use. Obstetrical tape is superior to catgut or braided nylon, as it is softer and less likely to act like a ‘cheese wire’. Baler twine and safety pins are not recommended.

Several suture techniques are described to close the vulval lips. Horizontal mattress sutures are straightforward, but have the disadvantages that they can cause further straining and there is a tendency for them to pull through the skin when under tension. A purse-string of umbilical tape under the skin around the vulva is more satisfactory and causes minimal tissue reaction. Your vet can demonstrate the most appropriate method for your ewes.

5. Control inflammation: Your vet may recommend the use of antibiotics and anti-inflammatory drugs in cases where inflammation or trauma are obvious.

6. Removal of the sutures: It is important that prolapsed ewes are clearly marked so that the sutures can be removed before lambing and assistance given if required.

Neil Sargison BA VetMB DSHP FRCVS