MAF Advice on Bearings in Ewes

13 July, 1999

Bearings (prolapses of the vagina) in ewes can be a problem every year as lambing approaches, even on the best managed farms. A senior animal welfare adviser for MAF's Enforcement Unit, David Barbour, said dealing with bearings means careful scrutiny of flocks several times a day as ewes approach lambing, with prompt treatment of early cases.

The cause of bearings is complex, Mr Barbour said, but one major factor was increased pressure in the abdomen. The reasons for this included a womb full of lambs, a full rumen, a full bladder and a lot of abdominal fat.

Mr Barbour said that in the fifth and the last month of pregnancy, it is not wise to try to prevent bearings by trying to reduce ewe body weights. "This will only predispose ewes to metabolic diseases such as sleepy sickness."

Other factors include slackness of the ligaments around the birth canal, sometimes associated with poor nutrition, so although it is often fat ewes that prolapse, ewes in lean condition are susceptible too. It has been suggested that low magnesium status and possibly low calcium status may be involved, and another theory is that selection for ease of lambing has resulted in ewes with a generous birth canal which is more likely to prolapse.

Treatment of prolapsed ewes always involves replacing and retaining the bearing, but in advanced cases Mr Barbour said the most humane option was euthanasia. "Farmers who are unsure what to do in the event of their ewes developing bearings should consult a veterinarian at the earliest opportunity."

Treatment involves cleaning the prolapsed mass very carefully and gently replacing it, then holding it in place. "The bearing is very easily damaged, and infections will occur unless great care is taken to clean and gently press it back into place without causing damage."

Holding the prolapse up to allow the bladder to empty before trying to replace it is important, he said. Facing the ewe downhill or elevating her hind end aids replacement. Lubricant helps greatly. Antibiotic injections are necessary to prevent serious womb infections.

Once a ewe has prolapsed it is very likely that the bearing will be pushed out again unless it is somehow retained, because the damage done to the vagina during prolapse causes irritation which in turn causes straining. The gentlest method of retaining prolapses involves tying wool over the vulva.

Another simple and often effective technique involves using a length of baling twine placed in front of the pelvis bones (pin bones), brought down the sides of the ewe, inside each hind leg, crossed over the vulva and tied back onto the string where it string goes over the ewe's back in front of the pin bones. The string should be sufficiently tight to prevent the prolapse from recurring.

Commercially-available bearing retainers can be used. Like the tied wool and simple string techniques, these have the advantage that the ewe can lamb past them. However they should be removed as soon as lambing begins.

There are other methods of retaining bearings. Some of these involve stitching or clipping the vulva closed. This can be effective if carried out skilfully and hygienically, and if the stitches or clips are removed at lambing.

Contact person:
David Barbour, MAF Enforcement Unit, P O Box 271, Rangiora
Phone 021 337 128 Fax 03 313 0045.

  

 

Last Updated: 20 September 2010

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