DYSTOCIA in the mare is one of
the true emergencies that occurs in
equine practice.
Madeline Campbell, president of
the BEVA, who practises in Sussex,
outlined “Dealing with dystocia in the
field” in a paper presented during the
BEVA congress in September.
In thoroughbreds, about 4 % of
parturitions give rise to
dystocia with a higher
incidence, around 10%, in draught
mares. Normal birth
in the mare happens
rapidly and foal
survival is inversely
proportional to the
length of second stage
labour.
It is essential for
the owner to recognise
when the mare is in
trouble so the practice
needs to have done
good work on client
education well in
advance of the
expected date of foaling.
There are basic time-lines: the
mare should foal within 24 hours of
waxing up and second stage labour
should take no more than 20 minutes.
The owner needs to know that any
dripping milk is abnormal, colostrum
that is produced before foaling must
be saved and given to the foal, which
is at risk of insufficient intake of
antibodies and energy.
Avoid suffocation
In normal circumstances the allanto-
chorionic membrane ruptures at the
beginning of second-stage labour. If
the foal is born without rupture of
the amnion, a human needs to break
the membrane or the foal will
suffocate.
The umbilical cord should not be
broken as the foal needs all of the
blood that drains from the placenta. If
the cord is broken and bleeding it
needs to be clamped.
In the condition known as “Red
bag” there is premature placental
separation and a red velvety
membrane marked with the white
cervical star appears at the vulva. The
foal can be felt inside it and the
membrane needs to be ruptured and
the foal extracted quickly.
Advice covering this sort of
situation needs to be given by the
veterinary surgeon, perhaps while
driving to the foaling, as rapid action
is essential to save the foal. The mare’s
future reproductive career is the other
consideration: any intervention needs
to treat the reproductive tract as gently and carefully as possible.
The veterinary surgeon needs to have a full dystocia kit ready in the
car. This should include foaling ropes
and handles, a generous supply of
obstetrical lubricant (complete with a
stirrup pump and a sterile stomach
tube to get it into the uterus), drugs
for sedation and anaesthesia of the mare and revival of
the foal, an
“Ambibag” foal
resuscitator, and a
foal oro-tracheal
cuffed tube. A
fetotomy kit
completes the
picture.
There are four
stages of intervention in
dystocia. The first is
assisted vaginal
delivery (AVD). The
mare is standing and
may be sedated. Be
aware of human safety when treating
the mare: she can be distressed and may behave unpredictably.
Action plan
There needs to be an action plan
agreed with the owner before the
foaling. Is the priority to save the mare
or the foal? What are the financial
constraints? Will the owner want the
mare referred for hospital treatment if
the situation cannot be resolved by
AVD?
Plans as to where the mare can be
referred and how she is to be
transported need to be made in
advance. The referral hospital needs to
be able to assemble a team for a
caesarean at short notice. Delay and
indecision can mean death to mare or
foal or both.
The next stage is controlled
vaginal delivery (CVD). The mare is
anaesthetised, her hind legs are
elevated and the delivery is totally
under the control of the clinician.
CVD is best done in the anaesthetic
induction area of the hospital while
the mare’s abdomen is being clipped
and prepared for surgery.
If the foal can be delivered, all is
well, otherwise no time is lost in going
for the next stage which is caesarean
section. If the foal is dead, the fourth
stage, fetotomy, can be carried out in
the standing, sedated mare.
Survival
Having delivered the foal, the next
thing is to make sure that it survives.
Peter Morresey of Rood and Riddle
Equine Hospital in Kentucky gave us his views on “Identification and
management of the high-risk foal in
practice”.
It is important to establish the
value of the foal before starting on
intensive treatment as this is likely to
be expensive and prolonged and the
outcome is uncertain. The condition
of the mare, her uterus and the
environment in which the foaling took
place all need to be considered.
It is useful to know the history of
previous foalings and also to know
whether the mare had suffered any
illnesses during the pregnancy. Any
deviations from normal in the foal
need to be recognised and acted on
quickly.
The normal foal should achieve
sternal recumbency within 30 minutes
of birth. It should stand and feed
within two hours and it should have
urinated and defaecated within six to
10 hours.
If the foal is seen to be straining
with its back arched, it has problems
with defaecation; if its back is dipped,
the problems are with urination.
A weak foal that takes too long to
get up is more exposed to pathogens
from the ground, potentially leading
to sepsis and is more likely to suffer
hypothermia or trauma from getting
trodden on.
Is the foal a potential athlete?
Radiographs taken early on can
determine whether the animal is
structurally sound and worth working
with. A foal with fractured ribs is in
severe pain and will breathe shallowly.
Ultrasonographic examination
should be used to monitor for
haemorrhage. Ultrasound is also
useful in evaluating the bladder.
Healthy bladders do not rupture so if
there is any leaking sepsis of the
bladder wall should be suspected.
Don’t overfeed
In general, foals do not show pain as
an adult would. If the foal appears to
be depressed, look for sepsis,
starvation, hypoxic ischaemic
encephalopathy, neonatal
isoerythrolysis, as well as surgical
lesions.
Always look at the mare’s udder to
establish whether the foal has sucked.
A sick foal should not be overfed: it
can only take 10% of its bodyweight
daily as milk.
The sick foal demands close
inspection: for example, it is necessary
to examine its eyes and inside its
mouth and ears. A septic foal may
show haemorrhage in the sclera which
may indicate thrombocytopaenia.
Haemorrhage inside the mouth may
be due to trauma.
Any foal that shows lack of
interest in its mother is a cause for
concern. It may take eight days from
being born for any evidence of the
neurological dysfunction caused by
hypoxia to become apparent, though
this usually shows at around 24 to 48
hours.
Huge risk
The dummy foal that wanders off
and hides its head in a corner and is
not sucking is at huge risk, and this
can be underestimated by the owner.
Seizuring is obvious and, again, a
major problem.
Several parameters that are
reliable in the adult are not in the
foal. The heart rate and respiratory
rate, PCV and CBC are all
untrustworthy though the blood
lactate level is useful.
The foal must be kept warm,
using blankets, insulated covers or
bags of warmed fluid. It must not be
overheated and if it is hypovolaemic
this must be corrected with
appropriate fluid therapy or the
warming will increase the peripheral
circulation at the expense of the
blood pressure and so cause harm.
Restoring the fluid volume also helps
the brain.
Feeding needs to be parenteral if
the foal is cold as the perfusion of
the gut will be inadequate for proper
absorption of the nutrients.
So, overall, care of the mare and
new foal needs good strategy, a
practical plan that can be put into
action at speed and followed by
dedication and co-operation from
everyone concerned.
