Home' Clutha Leader : August 16th 2012 Contents 12
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Bearings a major issue for farmers
Bearings are by far the biggest problem at
Every year just before lambing every
farmer of breeding ewes is deeply concerned
that the forthcoming breeding period will not
be blighted by bearings. This really is a major
concern for sheep farmers all over New
Zealand, but no one has yet arrived at one
identifiable reason for bearings in breeding
ewes and there is now considerable support
for the view that it is caused by a combination
Just what is a bearing?
It's a vaginal prolapse. When the pressure in a
ewe's abdomen is greater than the strength of
the tissues supporting the vagina, the vagina
may be pushed outside the body. This
exposes the internal lining. The cervix, (at the
centre of the prolapse) is closed, as the ewe is
not ready to give birth. The ewe will have
difficulty or not be able to urinate.
Pressure in the abdomen can be increased by
an enlarged rumen, womb with foetal lambs
or a full bladder. This situation is worsened
when the ewe is sitting with her head uphill or
is straining. Hormones will influence
relaxation of the muscles and ligaments
retaining the vagina.
Bearings are most common in ewes near
lambing. However, they can occur all year
round, including in
Farm surveys (over
two years) in Hawke's
Bay and Southland
showed that over
60% of farms recor-
ded less than one
percent with bear-
ings. However, one
farm in one hundred
recorded over 5%.
The survey covered
118,000 ewes on 113
farms in 2000 and
136,000 ewes on 88
farms in 2001.
Incidents of bearings
can be very expensive for the farmer. The
losses of ewes and lamb or lambs rapidly add
up into thousands of dollars. Today with
reduced flocks and higher prices for lambs
this is something that cannot be borne by the
sheep farmer. In addition to the financial cost
there is the mental cost to farmers of having
to deal with bearings, and the animal welfare
In considering what causes bearings it is
important to bear in mind that there are still
large areas of unknowns and contradiction.
Some causes may
have large effects but
some may have smal-
include the number
of lambs carried, the
slope of paddocks
grazed near lambing
and a previous bear-
ing are the biggest
A ewe carrying
triplets is 11 times
more susceptible and
ewes with twins are
five times more likely
to have a bearing
than a ewe carrying a single lamb.
Running ewes on hill country rather than flats
means gravity will add pressure. Experts have
noted a trend for heavy ewes to face uphill to
reduce pressure on the diaphragm. This puts
pressure on the vagina muscles.
A ewe that has had a bearing the previous
year has a 30% or greater chance of having
another. Smaller risks have been found due to
feeding swedes or salt supplements in late
There are other factors for which there is no
solid evidence but which
appear logical and are suppor-
ted by farmer observations or
study include: bulky low-quality
feed during pregnancy:
autumn-saved pasture with
dead material in the base may
have fungal toxins that cause
vaginal muscles to relax (e.g.
Fusaria fungi or scopoletin in sweet vernal).
Oestrogenic substances (found in red clover
and subterranean clover for example) can also
Milk fever (hypocalcaemia): causes ewes to lie
down which increases pressure.
Another is a rapid change of feed quantity or
quality: This approach may encourage ewes to
gorge themselves, adding pressure to the
rumen. Some farmer observations indicate
that daily shifts may cause more bearings than
less frequent shifts.
Lack of exercise: from grazing on small flat
paddocks with easily obtained food for long
Several years ago at a Clutha 2000 seminar in
Balclutha, Errol Holgate, a highly regarded
sheep farmers expressed the view that in that
region, sudden increases in the quantity of
food available to pregnant ewes and lack of
exercise combined to increase the number of
incidences of bearings.
When bearings occur, however, all is not lost.
On discovering a ewe in this condition, first of
all lift bearing so ewe can urinate BUT Use
reduce the chance of Leptospirosis trans-
mission to the farmer.
Next, replace bearing carefully. Clean the
bearing first and use copious amounts of
lubricant to minimise damage to the soft
Having completed this, it is essential to retain
the bearing with a retainer/harness or stitches.
Only after these steps have been taken should
antibiotics be administered.
Finally, the farmer and his or her staff must
remember to remove retainer or stitches
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