Pregnancy - Horses Inside Out

and
Brought to you by...
Written by
Dr
and Dr Simon Robinson, BVSc BScAgr MACVSc Diplomate ACT
equinedentalvets.com.au
Pregnancy
committed to advancing horse health
“
”
The vast majority of
mares will go to term
and deliver a normal
healthy foal
While in the vast majority of cases the mare’s
pregnancy and foaling proceed normally and with
minimal intervention, there are a large range of
problems and complications that can occur.
Watch the Mare Reproduction video
online... www.equinedentalvets.com.au
Broodmare owners should have an
understanding of what is normal so they
can readily identify when something is
going wrong.
These are some practical tips for care
and management of mares during
pregnancy and around the time of
foaling.
Pregnant mare’s checklist
1
Check the last service date and
determine foaling date (the average
length of an equine gestation is
330 days from the last service date).
Remember that the normal range for
equine gestation period is 320 to 365
days and each individual mare will have
her “own” gestation length.
2
Ask your vet to perform a
pregnancy test on any mares that
don’t look pregnant or have a
history of slipping. If she doesn’t look
pregnant after 9 months, she probably
isn’t.
3
Keep pregnant mares separated
from other horses (especially
young horses that travel to shows/
events/ races) – this reduces the chances
of the pregnant mares catching Equine
Herpes Virus which is a respiratory virus
that can cause pregnant mares to abort.
4
Signs of problems that require immediate
veterinary attention include:
- Premature lactation
- Any discharge from
the mare’s vulva
- Signs of
discomfort
or colic
Nutrition – (For more detailed
information see page 21)
For the first 7 months of pregnancy,
the equine foetus represents a small
percentage of the mare’s weight and has
very small energy and protein demands
for growth. Hence, for the first 7 months
of pregnancy, the mare should be fed
the same as if she was not pregnant with
the aim of maintaining a good body
condition score. Excessive feeding during
early pregnancy can lead to obesity and
problems later on in pregnancy and at
foaling.
The late pregnant mare has greater demand
for energy, protein, vitamins and minerals
associated with rapid foetal growth from
the 9th month of pregnancy. Ensure the
late pregnant mare is on a good plane of
nutrition - aim to maintain body condition
of the mare from this time until foaling.
This will ensure that the mare is able to
produce adequate amounts of milk for
the foal and to resume her reproductive
cycles after foaling. The following are
recommended:
Good quality pasture supplemented with
1kg of 20-25% protein pellet daily
If pasture quality is limited – supplement
with 3-5kg of 13-15% protein pellet and
feed high protein hay (Lucerne or clover).
Equine Dental Vets an organisation committed to advancing horse health
Our group is made up of Equine Dental veterinarians from across the globe and we have over 300 members right here in Australia.
Most of our members provide afterhours and emergency care for all equine health issues and using our dedicated search on our
website you can find the Equine dental vets nearest you at the touch of a button. This is particularly useful if you are away from
home, for example when travelling to shows and competitions.
We are proud to provide you this healthcare information in partnership with Horses and People magazine.
www.equinedentalvets.com.au
Page 14 • HORSES and PEOPLE • Phone: 07 5467 9796 • [email protected]
The Pregnant Mare, Copyright of Gillian Higgins. Reproduced with permission. To see more of Gillian’s work visit www.horsesinsideout.com
5
6
Worming – mares should be
wormed in the last 4 to 6 weeks
of pregnancy and prior to
moving into clean foaling areas.
Vaccination – this provides
protection for the foal via
antibodies in mare’s colostrum.
Ideally boost at least 6-8 weeks before
the mare’s due date.
Vaccinate all mares for Tetanus and
strangles.
Herpes Virus (Duvaxyn) –
vaccinate in the 5th, 7th, 9th
month of pregnancy where there is
a history of herpes virus abortion
or a large number of horses on a
property.
On farms where there has been a
history of Salmonella or Rotavirus
diarrhoea, it is good practice
to vaccinate mares for these
pathogens as well.
7
8
Move the pregnant mare to the
foaling location at least 4-6
weeks prior to her due date in
order to expose her immune system to
the local environment and pathogens.
Open Caslicks if the mare’s
vulva is stitched up.
Monitoring mares during
pregnancy
All mares should be checked on a daily
basis throughout late pregnancy. If a mare
has previously lost or aborted a pregnancy,
she is considered to be a higher risk for
future problems during pregnancy and
should be monitored closely throughout
pregnancy.
Some signs to look out for that clearly
indicate problems are:
• Signs of premature lactation (mare
forms an udder/bags up early and/or
runs milk).
• Any discharge from the mare’s vulva.
• Signs of discomfort or colic.
If the mare shows any of these signs,
have her examined by a veterinarian
immediately as she may need treatment to
prevent her from delivering prematurely,
and the foal may need extra attention after
it is born.
Veterinarians can monitor the wellbeing
of the pregnancy (placenta and the foetus)
by using ultrasonography and performing
blood testing for certain hormones. Use
of ultrasound either rectally or through
the mare’s abdominal wall enables the
veterinarian to visualise both the placenta
and the foal.
Subtle changes in the placenta and foetal
fluids and the foetal heart rate can indicate
problems during late pregnancy. Similarly,
measurement of the mare’s progesterone
(hormone) level during late pregnancy
provides a useful indication of problems with
the pregnancy and associated foetal stress. It
is important to understand that a single blood
test to measure the progesterone level is of
limited usefulness alone due to normal daily
fluctuations in hormone levels in the mare
during late pregnancy.
There are a range of treatments which can
help to prolong the pregnancy of “highrisk” mares with placentitis and to increase
the chances of getting a healthy foal on the
ground from these mares.
Please contact your veterinarian if you have
any questions or would like some advice
regarding your pregnant mare(s).
Check out the...
Foaling Date Calculator
Download the FREE!
Foaling Fact Sheet
Go to:
http://www.
horsesandpeople.com.au/articles/
free-fact-sheets.html
www.horsesandpeople.com.au • HORSES and PEOPLE • Page 15
and
and
08 - Tru Breed - Horses and People.pdf 1 7/11/2012 5:03:56 PM
PREGNANCY COMPLICATIONS
I Think the Foal is Dead...
Many clients bring mares to our practice
convinced that their foals are dead. The
usual scenario is that they see a behaviour
change and stop seeing flank movement.
My odds run about one hundred
thousand to four that the foal is alive - if
she really was in foal.
In twenty eight years of practice, I have
seen one dead mummified fetus, and it
was in a mare that had not cycled for over
a year. The perfectly formed fetus was
clean and had most likely been there for
a year without causing any damage to the
mare (see image 1).
Never say never, but if the foal is dead the
chances are the mare will abort it.
I also had one mare with a live foal in her,
and the mare had no interest in anything
other than eating, even though her cervix
was so open you could drive a truck in.
C
M
Y
CM
MY
CY
CMY
K
I had two mares with long-dead foals and
again no signs of labour, but they had
vaginal discharges which are a clear sign
that there is a problem.
In the last few weeks of pregnancy the
foal moves up into the pelvic canal and
this is why visible flank movement is
rarely detectible. So unless your mare has
a discharge from the vulva, the chances
are she is still in foal and the foal is just
jammed in the birth canal and still alive.
Even the pros get fooled
One of my favorite foaling stories is from
my own father who was a noted equine
reproductive veterinarian. He decided to
video his own mare that appeared to go
into active labour in the light of day. As a
new graduate, I was there to help.
As an afterthought we decided to wrap
her tail so we could get good visuals. We
stood her up and wrapped the tail.
That stopped any further
contractions and after an
hour of watching we gave
up for the day. We were
sure she would foal that
night. But alas several days
later we still weren’t seeing
any signs of foaling.
Nevertheless, dutiful daughter and newbie
vet did as the boss directed, and to both of
our astonishment she was empty. She had
not been in foal for months according to
her virginal small uterus! So, even the pros
get fooled.
The vast majority of mares will go to
term and foal a normal healthy foal, late
pregnancy complications such as the
ones described below are all rare events,
but ones to keep in mind when you are
observing your mare’s pregnancy develop.
Teasing but pregnant
In the early stages of pregnancy most mares
stop teasing or showing signs of oestrus,
however, some mares continue to tease
throughout the pregnancy.
When a supposedly pregnant mare shows
signs of teasing she should be checked
by either manual rectal, or preferably
ultrasonic examination to ensure she has
not lost the pregnancy. Although rare, she
may tease right throughout the pregnancy.
Pre-pubic tendon rupture
Pre-pubic tendon rupture can be a problem
in advanced pregnancy. The tendons
that attach to the pelvis and that connect
the abdominal muscles supporting the
abdomen can become stretched and
rupture.
In the early stages of the rupture there may
be some swelling in front of the udder.
This can be confused with normal late
pregnancy edema. Normal edema usually
occurs in the last two week of pregnancy
and often starts in the middle of the
abdomen and can extend from the udder
to the chest or pectoral region.
Pre-pubic tendon rupture is a life
threatening condition.
Below: Pre-pubic tendon rupture (ppt)
courtesy of: Jan Govaere
The next morning my dad
called me up to perform a
rectal exam on that mare.
He had a funny feeling. His
arm was broken and he was
unable to do the job. I took
one look and said it was a
waste of time as she was
big as a house, and afterall
we had seen active labour.
Page 16 • HORSES and PEOPLE • Phone: 07 5467 9796 • [email protected]
As the rupture progresses there is often
blood loss and loss of the muscles ability
to contract and expel a foal.
In some early mild cases mares can be
managed with slings and support, but often
pre-pubic tendon rupture results in loss of
the mare and a pre-term fetus. If the tear is
in early pregnancy the pregnancy should
be aborted and veterinary assistance will
be needed to assist in delivery.
Ultrasonic examination can aid in the
diagnosis in mild cases. While mares with
normal edema are slightly uncomfortable,
mares with pre-pubic tendon rupture often
show obvious signs of discomfort and may
look colicky and lay down frequently. The
tearing of the musculo-tendonous area can
also result in severe blood loss.
Failing the above, surgery is always
an option. Successful outcomes range
in the sixty percent range, but speed
of recognition of the problem and
correction are the key to a favourable
outcome.
Hydrops allantois
This is another rare condition. It
is a placental or foal abnormality
where there is an accumulation of
amniotic fluid surrounding the fetus
causing a distension of the uterus and
compromising the abdomen. While it
can be a slow onset, it is often rapid and
symptoms of the mare include a large
abdomen, lack of appetite and mild
colic.
Dental disease causes pain and
suffering for many horses.
It is very common, and often left
untreated or incorrectly treated,
due to a lack of understanding,
poor equipment and limited
training in this field.
Uterine Torsion
In rare cases the uterus can rotate inside
the mare. This causes compromises of
blood flow to the uterus with stretching
and compression on the arteries feeding
the uterus and the developing fetus. This
usually occurs during the last trimester of
pregnancy.
The causes may be a large fetus in a small
uterus, an over active foal or rolling of the
mare herself.
The symptoms are very similar to colic,
therefore all ‘colicky’ mares in advanced
pregnancies must be evaluated for possible
torsion. This is done by rectal examination
and in some cases by vaginal examination.
The treatment is to rotate the uterus back
into position. This can be done in a
number of ways but the most expedient
and often used method is the Schaefler
technique where the mare is anesthetized
and then a board is placed on her
abdomen. A person large enough stands
on the board and the mare is rolled in
the same direction as the torsion. This
procedure takes several people and you are
advised not to try this without the adivce of
an experienced veterinarian and significant
manpower! (see image below).
If rolling fails and the mare is near term,
and or if the cervix is open, the foal can
be grasped through the cervix and rocked
to attempt to rotate the foal and uterus in a
standing position.
Below: Don’t try this alone!
Schaefler technique for uterine torsions
courtesy of John Hyland.
equinedentalvets.com.au
Hydrops in a Mini mare. It is an accumulation
of amniotic fluid causing distention of the
uterus; the deformed foal was born live but
died within an hour of birth.
Equine dental veterinarians have
the knowledge, experience and
equipment to prevent pain and
offer horse owners the piece of
mind that comes from working
with professionals.
• Find a dental vet in your area
• Learn about horse dentistry
• How to choose a good
service provider
In most cases it is accompanied by
a gross abnormality of the fetus. It is
thought that the fetus is unable to
swallow the amniotic fluid and eliminate
it via their kidneys and blood stream
there by eliminating the evacuation of
normal amniotic fluid (see image 6).
If the foal is determined to be abnormal,
it may be necessary to induce the labour
and the mare will likely need assistance.
Mares are reported to be susceptible
to hypovolemic shock, where internal
systems begin to shut down due to rapid
loss of fluid from the abdomen. There
is no treatment, but it is advisable to
differentiate this from twins. Ultrasonic
examination is helpful.
In the case pictured above, the uterus
was examined at near term both by
palpation and ultrasound and no fetus
could be palpated or seen by rectal
ultrasonic examination. Her uterus was
huge and fluid filled. The mare produced
a live but deformed foal that died within
an hour of birth. Speculation that this
foal was unable to drink the amniotic
fluid was due to severe dwarfism.
Use our site to find equine dental
vets in your area and learn more
about equine dental care and
health.
All veterinarians undergo extensive
training in providing animal health
care, and the vets listed on this site
have all completed recognised
further training specifically in
equine dentistry.
Scan me with your smartphone
equinedentalvets.com.au
www.horsesandpeople.com.au • HORSES and PEOPLE • Page 17
Placentitis is the term for inflammation
(usually due to infection) of the placenta.
The placenta is the intricate connection
that forms between the uterus of the
mare and the foetus. It is also termed the
afterbirth (as it is passed after the foal has
been delivered) or the foetal membranes.
The placenta is the life support system
for the developing foetus, providing
nutritional support and oxygenated blood
via the umbilical cord. When the placenta
becomes inflamed, usually due to infection
travelling along the mare’s reproductive
tract from the cervix, it becomes thickened
and the connection between the uterus
and the placenta becomes compromised.
This can cause foetal stress and ultimately
premature delivery of a dead or highly
compromised foal.
Abortion due to herpes virus can occur
without any other obvious signs of
illness. Furthermore, the aborted foetus
and membranes are a concentrated
source of virus that can infect other
mares.
Viral abortion
Twins
Mares can start to leak milk about two
weeks prior to their due date. While this is
not good, it does not necessarily indicate a
compromised pregnancy.
On the other hand, lactation well before
the due date often signals a problem with
the placenta and the developing fetus.
It is more common for mares with twins to
start lactation early. This may be due to the
death of one of the twins, or because the
placenta is not able to accommodate the
growing size of both foals.
Other causes include placentitis from either
bacteria or fungi growing in the uterus.
Diagnostic ultrasound of the placenta and
uterus can give useful information.
If the premature lactation coincides with
a vulvar discharge, then it is important
to consider placentitis and institute
treatment ASAP including antibiotics,
anti-inflammatories and progesterone like
supplementation.
Equine herpes virus (EVH1) is a respiratory
virus of horses that can also cause abortion
in late pregnant mares. It is considered
common in Australia, particularly in
racing stables and groups of young horses.
The virus is spread between horses via
Why you should keep a colostrum bank
Katy Driver
When mares leak milk at the end of
the pregnancy in the last week or so,
this may not indicate a problem with
the fetus, but can cause problems
when the foal is born. The precious
colostrum may be lost in the leaked
milk and the foal may require
supplementation of colostrum from a
‘bank’. It is a good idea to source out places to get colostrum in case of an emergency.
If you are breeding a few mares each year you may want to make your own bank.
If you have a mare with lots of colostrum make sure the foal gets a few sips then
take ~1/4 to ½ cup and strain it and then freeze it. Assuming the mare donating the
colostrum and foal prosper well then the milk will most likely be fine for another foal
later. You can give foals colostrums from different sources without too much risk. This
needs to be done in the first 6 hours after birth for ideal immunoglobulin absorption.
Plasma transfusions equal the cost of ink cartridges so an ounce of prevention really is
cheaper than the pound of cure…
the mouth and airway and is highly
contagious. Pregnant mares should
always be kept separated (no direct
contact across fences) from other groups
of horses (young horses, race horses,
agisting horses).
Whenever a mare has been found to
abort her pregnancy, other pregnant
mares should be removed from the area
until the mare and foetus have been
examined and tested by a veterinary to
exclude herpes virus as a cause of the
abortion.
“But I had my mare scanned!” Advanced
twin pregnancies occur infrequently,
and while most don’t go to term and
abort mid to late gestation, some, like
the gorgeous twins pictured on the next
page, do go all the way. Nevertheless,
twinning is definitely a situation to be
avoided. If the pregnancy goes full term,
the foals born are often small and weak
and success stories are rare.
Late-term signs include an enlarged
abdomen and premature lactation.
Rectal examination may help in deciding
if twins are present but in late gestation
the chance of missing a twin is not
unusual.
ECG’s of the abdomen may differentiate
the presence of three heart beats, but
even this is not always a hundred
percent accurate.
The estimate of twin conceptions is
around ten percent of all pregnancies,
but by day forty, seventy five percent
of them will have self reduced. If the
embryos implant in opposite sides of
the uterus then the chance of a natural
reduction is much smaller.
HORSES INSIDE OUT
Understanding How Your Horse Works Improves Performance
Anatomy & Biomechanics made easy with
Books & DVDs by Gillian Higgins
www.HorsesInsIdeout.com
Page 18 • HORSES and PEOPLE • Phone: 07 5467 9796 • [email protected]
Above: The Eastern Tent Caterpillar is believed to be the
cause of Equine Amnionitis and Fetal Loss Syndrome.
In the early stages of pregnancy there are many tools that
vets can use to eliminate twins, ranging from crushing to
intra cardiac injection of procaine penicillin.
”
The Good News: These are all rare events.
The vast majority of mares will go to term
and foal a normal healthy foal.
When advanced twin conceptions are found there is little
to be done, and while the mare can be aborted under
supervision, most people allow the pregnancy to continue
to termination which in most cases is midterm abortion.
These mares are candidates for future twinning. So the best
way to prevent late term discovery of twins is from frequent
ultrasonic examinations in a properly lit environment
during the 16-22 day period.
Equine Amnionitis and Fetal Loss Syndrome
This is a syndrome that has occurred primarily in NSW and
Kentucky, although there have been a few cases of this
occurring in Victoria and Queensland. Abortion occurs at
any time during the pregnancy.
The presumed cause is the ingestion of the Eastern Tent
Caterpillar. The caterpillar has microscopic barbs that
penetrate through the intestinal mucosa and enter the fetus.
They carry bacteria that then kill the growing fetus.
The only prevention is the removal of the horses from the
environment where the horses eat. Again these horses
require frequent ultrasonic examination, antibiotics,
progesterone like product and anti-inflammatories,
Tennyson Stud
Lactation occurring before the normal
expected ranges is a serious clinical sign of
placental abnormality.
wikipedia.org
Placentitis
and
“
and
Premature Lactation
Twisted Umbilical Cord
Most foals are born with numerous twists in their umbilical
cord. A small percentage of these actually twist enough
to strangle the foal
and cause abortion.
Unless there is
accompanying
oedema in the cord,
this is probably not
the cause of the
abortion and other
causes should be
identified.
Twisted umbilical cord.
Courtesy of Elizabeth Woolsley
In 2011 these gorgeous twin foals by Worldwide PB were born at Tennyson
Stud, and both are still thriving today. Tennyson Stud, a small stud in the
picturesque Hawkesbury Valley NSW imported the warmblood Worldwide
PB from New Zealand in 2005 where stud owner and manager Claire Seidl
campaigned him through from Elementary to FEI level. As we write this,
Worldwide PB and Joann Formosa who featured in our July Rider Profile are
taking part in the London Paralympic Games!
For Further Reading:
http://www.vetmed.lsu.edu/eiltslotus/theriogenology-5361/equine%20abortion_2.htm
http://www.ansteadvet.com.au/veterinary-articles.php?id_art=42
ABOUT THE AUTHOR: Simon Robinson is a
Registered Specialist in Equine Reproduction and an
Equine Dental Vet. He has been involved in equine
breeding and stud practice for many years. Originally
from Sydney but after qualifying as a veterinarian
Simon spent 6 years working as an ambulatory and
stud veterinarian at the Goulburn Valley Equine
Hospital in Victoria. Prior to his veterinary career
Simon managed one of the largest equine studs in
the Southern Hemisphere. He has a vast amount of
experience in equine reproduction and is a Diplomate of the American
College of Theriogenologists (specialist qualification in veterinary
reproduction). Simon’s veterinary interests extend to equine internal
medicine and he is a Member of the Australian College of Veterinary
Scientists (Equine Medicine). Simon also breeds and races Standardbred
horses and owns a highly successful show pony.
You can find out more at www.victorianequinegroup.com.au
www.horsesandpeople.com.au • HORSES and PEOPLE • Page 19