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Abdominal
distension will be a feature of mares in the latter
part of pregnancy, and this will correspond with a
decrease in exertional activity. In the last 2 - 3
weeks of gestation a relaxation of the abdominal muscles
with a consequent 'dropping' will become evident,
this being particular evident on older mares which
have gone through a succession of pregnancies.
At
the same time relaxation of the muscles round the
hind quarters tends to create hollows either side
of the root of the tail, which become more apparent
about 4 weeks before full term, enlargment of the
udder will be apparent, this process continuing with
fillinf of the teats by a clear viscous secretion
which typically, 24 to 48hrs before foaling coagulates
to form the candle wax appearance at the end of the
teats. At 12 to 24hrs before foaling, in the classically
'normal' situation, this was liquefies and colostrums
can be expressed. The above description of events
can be regarded as 'normal' but wide variations occur
which lead to foalings which are completely uncomplicated
in every respect.
In professional parlance,
the act of foaling is devided into three phases:
1 Intra-uterine changes are
taking place
and there may be little or no evidence of these changes
externally. Some mares may appear restless and exhibit
patchy sweating. In phase 1 there is no visible effort
on the part of the mare, but uterine involvement has
already begun. During this period a dramatic repositioning
of the foal is occurring in that the foetus moves
from lying on its back with knees flexed and head
resting between them, to being right way up with front
legs and head extended into the birth canal. This
phase can last up to four hours.
2 Actual delivery commences.
and the appearance at the lips of the vulva of a balloon-like
sac of allantoic fluid indicates that this phase is
under way. Soon, with increasing pressure, this sac
will rupture and allantoic fluid will be released.
This is the characteristic 'breaking of the waters'.
During this phase the mare will nearly always lie
down and commence proper abdominal contractions involving
muscular effort.
These contractions will commonly occur in a series
of three or four, with rest periods intervening, and
indeed the mare will often rise and wander around
the box, particularly if they are maidens and somewhat
anxious about the whole process. Soon the foal will
make its first apperance, typically in the form of
one fore foot, which is followed by a second 20 to
40cms behind it.
The fore legs are closely followed by the nose. This
phase labour averages about 20 minutes, although considerable
leeway either side of this can be completely normal.
Complete delivery of the foal takes place in this
phase, although often the lower hind limbs of the
foal will be still within the mare. It seems superfluous
to remark that the first breaths of the foal are crucial.
Serious bran damage can occur at this stage if there
is any oxygen starvation to the brain.
The foaling attendant should ensure that the nostrils
of the foal are clear and in particular that no parts
of the foetal membrane are covering the newborn's
muzzle. It is also ideal if both mare and foal lie
quietly for ten minutes, with the two still being
connected by the umbilical cord. The contraction of
the now empty uterus pushed placental blood into the
foal giving it a boost and optimum start in life.
In reality this period of inaction is often much shorter,
and indeed with younger or first time foaling mares,
may not happen at all as quite often complete delivery
takes place while the mare is standing.
Sooner or later, either struggling on the part of
the foal or the mare getting to her feet will break
the cord at its predetermined weak point a few centimetres
from the foals abdomen. As soon as practically possible,
the umbilical stump, which should stop bleeding almost
immediately, should be dressed with an anti-bacterial
solution, the most efficient is reckoned to be 0.5%
chlohexidine. In the normal uncomplicated foaling
phase 2 is a rapid process. Equally problems can arise
with similar swiftness and time is of the essence
in order to prevent potentially serious and even lethal
complications.
The
vast majority of deliveries are uncomplicated.
nevertheless, one
should try to be present at the event, and even more
importantly, be in a position to summon veterinary
assistance quickly. Call you vet if:- After one hour
of phase 2 ie. after rupture of the amniotic membrane
and no further progress is made. This may be due amongst
other reasons to abnormal positioning of the foals
and requires rapid correction If instead of pale whitish
amniotic membrane, a dark red velvety membrane should
appear intact, immediate action is called for, and
the attendant should attempt to rupture this membrane
with fingers or a suitable blunt instrument.
In those cases, early placental separation from the
uterine lining may have occurred imprisoning the foal
in a sac which is no longer capable of maintaining
life. If one or more legs having been presented, further
delivery is arrested. Again postional abnormalities
of the foal may be responsible and as with all such
cases, the sooner skilled assistance is available
the more successful the outcome. A normal vigorous
foal should be on its feet and at least making attempts
to suckle within 2 hours.
Some foals may take a little longer, particularly
when faced with uncooperative and often maiden mothers.
In such cases some form of restraint such as holding
the mare in a head collar, holding up a front leg
or even the use of a twitch may have to resorted to
so that the foal can access colostrums as soon as
possible. With regard to colostrums, some mares may
run milk during late pregnancy, but well ahead of
foaling and in so losing valuable colostrums which
is vital to the well-being of the newborn. If possible
this secretion should be milked from the mare and
deep frozen.
When the foal is fit to suck, the thawed secretion
should be given to the foal by teat or alternatively
administered via a naso-gastric tube by your veterinary
surgeon. Call your vet if:- If within 12hrs of birth
the complete placenta has not been passed by the mare.
Even today with the range of anti-biotic and other
drugs available to the clinician, it is still important
that no fragments of the membrane are retained within
the mare. If within the first 2 or 3 days if the mare
shows any signs of colic or other discomfort, as such
symptoms could be due to internal haemorrhage. Such
haemorrhage is into the broad ligmanent of the uterus
and it is not necessary or even common for blood to
appear externally for such a potentially fatal situation
to be present.
It is good policy to have your vet call and check
your mare and foal in the first 24hrs post foaling.
At this visit, the general condition of the mare and
foal can assessed and the placenta checked to see
that it is intact, as even small scraps remaining
within the uterus can lead ti infection, consequent
laminitis. This examination should include checking
for meconium retention in the foal and if history
warrants, a blood sample for immunoglobin to establish
whether enough colostrums has been absorbed. On many
studs, anti-biotics are administered routinely to
newborn foals with or without tetanus antitoxin, depending
on the vaccination history of the mare.
Finally, nearly all foalings
are completely uncomplicated.
If in doubt, however, it is much better to call the
vet unnecessarily rather than waste time and allow
a slight problem to develop into a serious one. In
foaling, time is of the essence.
I.M.S. Paton B.V.M & S., M.R.C.V.S Paton & Lee Veterinary
Surgeons, Hoo Hall, Rivenhall, Essex.
Tel: 01376 513369, 01702 551600, 01206 262371
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