FOAL EMERGENCIES
Terry C. Gerros, DVM, MS, Diplomate, ACVIM.
Assistant Professor, Large Animal Medicine
Oregon State University
INTRODUCTION:
The signs of illness in foals are often vague and nonspecific. This
means that you
should be familiar with normal behavior in order to recognize problems early.
Dramatic
changes in a foal's condition can occur very rapidly. The wait and see approach
used in adult
equine medicine can be disastrous when dealing with the neonate. A short time
delay in the
institution of therapy can make the difference between success and failure.
It is my opinion than any foal which appears ill constitutes an emergency. Below
are listed the
normal parameters for foals in the immediate post-partum (post foaling) period.
NORMAL PARAMETERS:
1) Gestational age: 341 ñ 21 days. Range = 315 - 365 days.
2) Time to sucking reflex: Ave. 20 minutes post-foaling.
3) Time to standing: Ave. 57 minutes, range 15 - 165 minutes.
4) Time to nursing: Ave. 111 minutes, range 35 - 420 minutes.
5) Body temperature: First four days: 99 - 102F.
6) Heart rate: Ave. first five minutes: 70 bpm
6 - 60 minutes: 130 bpm
9 - 43 hours: 96 bpm
7) Respiratory rate: First 15 minutes: 60 - 80 bpm, then 20 - 40 bpm.
8) First urination: Ave. 8.5 hours after birth, colts earlier than fillies.
9) Meconium passage (first stool): Within first 24 hours.
10) Menace response (Blink response): Not present until 2 weeks of age.
NORMAL GUIDELINES USED TO ASSESS NEONATAL VIABILITY:
Adaptive response Time Elapsed Since Birth
Normal respiratory and cardiac rhythm Within 1 minute
Righting reflexes established Within 5 minutes
Sucking reflex established Within 30 minutes
Attempts to stand Within 60-120 minutes
Ability to stand unassisted Within 60-180 minutes
Nurses from udder Within 60-180 minutes
As I previously said, any of these parameters outside the given normal
range, either
high or low, should be considered abnormal. If they appear so, it is time to
call your
veterinarian.
Some abnormalities which you can pick up and give you an indication
that things are
amiss include:
1) Increased passive range of motion of joints.
2) Tendon contracture. Flexor tendon laxity (walking on their fetlocks).
3) Angular limb deformities (eg.knock knee'd).
4) Entropion (lower eyelid rolled under).
5) Tipped ears, velvety hair coat (prematurity).
6) Heat, swelling, or pain at joints or physes (growth plate).
7) Fractured ribs associated with foaling (rapid, shallow breathing).
8) Umbilical or inguinal (scrotal) hernias.
9) Cleft palate (milk running out of the foals nose as it nurses).
10) Scoliosis (curved), kyphosis (flexion), or lordosis (extension) of the
spinal column.
11) Injected (blood shot) or icteric (yellow) sclera (whites of the eyes).
12) Straining to defecate or urinate.
13) Red line around the coronary band (will only be evident on white footed
animals).
14) Swollen, moist, leaking umbilical cord.
15) Foal wanders away from the mare or in unaware of the mare in the stall.
16) Poor suckle reflex.
17) Placenta is thickened, discolored.
While we spend alot of time looking at the foal, don't forget that the
mare can give you
an indication that the foal is becoming ill before the foal shows a significant
change in
character. Examine the udder, milk, and vulva for signs of disease or infection.
A full tight
udder indicates a foal that isn't nursing. Malodorous uterine discharge may
indicate the foal
has an infection which developed in utero.
CONDITIONS ASSOCIATED WITH HIGH RISK NEWBORN FOALS
MATERNAL CONDITIONS:
Purulent vaginal discharge Fever
Hydrops allantois General anesthesia
Colic surgery Endotoxemia
Excessive medication History of previous abnormal foal
Premature lactation Poor nutritional status
Prolonged transport prior to foaling
CONDITIONS OF LABOR OR DELIVERY:
Premature parturition Abnormally long gestation
Prolonged labor Induction of labor
Dystocia Early umbilical cord rupture
C-section
NEONATAL CONDITIONS:
Meconium staining Placental abnormalities
Placentitis Twins
Orphan Inadequate colostral intake\
Immaturity/prematurity Exposure to infectious disease
Trauma
SPECIFIC DISEASES OF THE EQUINE NEONATE
It should be obvious to you that we can not possibly go every disease
condition which
constitutes an emergency in the time allotted to us. It is likely that the
physical abnormalities
associated with trauma constitute an emergency and need not be covered, except
your initial
management until the vet arrives. Certainly there are going to be conditions
which arise in
which nothing can be done, except euthanasia. This is something we as
veterinarians deal with
on a day to day basis, and not something we take lightly. I will outline some
conditions which
I deem are not treatable medically or surgically, briefly, and then discuss some
of the more
common diseases seen.
Untreatable diseases:
1) Microphthalmia/Anophthalmia
2) Ventricular septal defect
3) Trilogy/Tetralogy/Pentalogy of Fallot (multiple cardiac defects)
4) Atresia coli*
5) Atresia ani*
6) Choanal atresia*
7) Fractured spine
8) Fractured femur
9) Premature foal (less than 300 days into gestation)*
* Constitute diseases which may have a treatment option, however, the
prognosis going into
treatment is grave.
Lacerations and long bone fractures can initially be managed with
pressure wraps and
support bandages until the vet arrives. Unless you have specific questions we
won't go into
this further.
The conditions I will concentrate on will include failure or partial
failure of passive
transfer, neonatal isoerythrolysis (red blood cell lysis), neonatal
maladjustment syndrome, and
ruptured bladder.
PASSIVE TRANSFER DISORDERS OF THE FOAL
In order for the foal to fully fight off infection early in its life,
it must ingest colostrum
(first milk) which contains the antibodies which protect the foal from many
diseases. There
are special cells in the gastrointestinal tract which will absorb these
antibodies. These special
cells are replaced within the first 36 hours of life, so it is essential that
the foal nurse within
the first 6-8 hours of life, the time of peak absorption. Antibody absorption
decreases rapidly
afterwards. We like to see the foal nurse within 2 hours and certainly by 3
hours after birth.
The earlier the foal nurses, the more antibodies it absorbs, the more protected
it becomes.
These foals do not show any evidence of disease and a diagnostic test is the
basis of detecting
the disorder.
CAUSES OF FAILURE OF PASSIVE TRANSFER
1) Premature lactation (loss of colostrum before birth).
2) Inadequate colostrum production by the mare or poor colostral quality.
3) Delayed onset of sucking (foal that is slow to get up).
4) Malabsorption by the small intestine.
5) Prematurity: <320 days, the foal may be capable of absorption, but colostrum
may not
have formed.
Detecting 800 mg/dl of IgG in the foal is considered to be the minimum
concentration
for adequate passive transfer. Less than 400 mg/dl is considered to be complete
failure of
passive transfer. These foals are considered to be at greatest risk for any
development of
infectious disease. There are no specific abnormal clinical signs associated
with failure of
passive transfer and the foals act normally until they develop some disease.
How do you tell if the foal got a good quality colostrum and an adequate amount?
If the mare dripped milk for any appreciable time before foaling,
assume that she has
lost her colostrum. If you notice this happening, milk her out and save that
milk. Freeze it.
Would I collect the milk till she foals, you bet. If the mare doesn't drip milk
before foaling,
collect some of the colostrum and measure the specific gravity. An device used
to measure
antifreeze in your car radiator will suffice. If all the balls float, you can
assume the colostrum
to be of good quality. This corresponds to a specific gravity of about 1.060. Of
course, this
is a rough estimate. Once the foal nurses, you can measure the IgG content at
18-24 hours
after the foal nurses. Several tests are available, some even foal side. The
Cite Test can be
performed on whole blood, plasma, or serum and can be done on the farm.
Treatment of this disorder depends upon when you detect a problem. If
you know the
foal hasn't nursed and it is less than 12 hours old, oral administration of
colostrum ( 3 liters)
is the treatment of choice, followed by testing for adequate absorption. If the
foal is over 24
hours old, a plasma transfusion is required to bolster the IgG concentration.
The foal may
need between 1 - 3 liters. Plasma administration should take place over several
hours,
however, it may not be practical to administer it this slowly. Adverse
transfusion reactions
include shivering, elevated respiratory rate, anaphylactic reactions have
occurred and resulted
in death.
NEONATAL ISOERYTHROLYSIS (NI)
This is a severe hemolytic disease caused by incompatibility between
the mare's and
stallion's bloodtype. It is rarely seen in maiden mares as the mare must be
sensitized to
antigens from the stallion's red blood cells (RBC) in order to produce
antibodies against them.
These antibodies are then concentrated in the colostrum of the mare and passed
on to the foal
after birth. If the foal has inherited incompatible RBC antigens from the
stallion and ingests
colostrum containing antibodies directed against those antigens, NI may ensue.
Mares may
become sensitized by previous blood transfusion with blood of a similar type to
the stallion or
by transplacental RBC leakage during pregnancy.
CLINICAL SIGNS:
1) Foal born healthy, with the onset of the disease between 6 - 96
hours of age.
2) Severity of signs is dose dependent, peracute (found dead) to few clinical
signs.
3) Packed cell volume (PCV) <20%
4) Pronounced icterus (yellow, jaundice) of mucous membranes.
5) Tachycardia (elevated heart rate)
6) Progressive weakness
These foals usually are not febrile (fever) and may or may not exhibit
hemoglobinuria (dark
colored urine).
The diagnosis is based upon clinical signs and cross-match the mare and foal.
1) Treatment consists upon the severity of clinical signs. If
diagnosed before 24 hours of age,
muzzle the foal, milk out the mare and feed the foal colostrum from another
source.
2) If the PCV is <15% or the foal is very weak, keep the stress to a
minimum. Blood
transfusion will also be required at this point. The mares washed RBC's provide
the best
source. If this is impractical to accomplish, an aged gelding who has not had a
blood
transfusion is an alternative source. Those horses known to be A- and Q-type
negative are
good blood donors.
3) Other supportive care may be required, consult your vet.
4) Look for other problems.
NEONATAL MALADJUSTMENT SYNDROME (Barkers, Dummies, Wanderers)
A noninfectious central nervous system disorder of neonatal foals
associated with
behavioral abnormalities. The syndrome usually is first seen anytime after birth
to 24 hours of
age. These foals may be completely normal at birth, had a normal gestation and
parturition.
The foaling may have been difficult or the foal may have suffered some hypoxic
(low oxygen)
episode.
The clinical signs associated with this disease relate to derangements
of cerebral
function or spinal cord disease, or both.
Central signs:
1) Loss of suckle reflex
2) Aimless wandering, may appear blind
3) Hyperexcitable with jerky stiff movements or unresponsiveness
4) Extensor spasms of neck, limbs, paddling
5) Chomping or teeth grinding
6) Abnormal vocalization
7) Anisocoria (one dilated and one constricted pupil)
8) Abnormal respiratory patterns
9) Hypothermia (low body temperature), acidosis
10) Coma, death
Spinal cord signs:
1) Weakness
2) Ataxia (incoordinated)
3) Depressed local reflexes
This disease needs to be differentiated primarily from septicemia.
Often times these
syndromes appear similar. A complete blood count will help differentiate the two
diseases.
Serum biochemistry panel may also show abnormalities in septic foals where NMS
foals will
be normal.
Treatment:
1) Control convulsions
2) Maintain body temperature, hydration, caloric intake, electrolyte and
acid-base
balance, and blood glucose.
3) Oxygen therapy as needed
4) CNS edema
5) Ensure adequate passive transfer
6) Physical therapy
7) Broad spectrum antibiotics.
This is a multisystemic disease and many of the patients concurrently
have ongoing
sepsis, failure of passive transfer, enteritis, ulcers, etc.
SEPTICEMIA
This is probably the leading cause of death in neonatal foals. It
usually involves a
gram negative bacteria which gains access to the circulatory system. The primary
routes of
infection are the respiratory tract, gastrointestinal tract, and umbilical cord.
It may be
acquired in utero or in the immediate post-partum period. These foals may be
born normal or
are weak right after birth. If they appear normal at birth, they may deteriorate
in a matter of
hours. This out of all the diseases discussed previously is truly an emergency
and needs
attention as soon as it noted the foal to be ill.
The clinical signs associated with septicemia include:
1) All ten signs listed under NEONATAL MALADJUSTMENT SYNDROME
2) Bright red mucous membranes (gums and conjunctiva)
3) Cyanotic (bluish) mucous membranes (gums)
4) Hemorrhages present on the gums
5) Injected sclera (blood shot eyes)
6) Elevated heart rate
7) Elevated respiratory rate
8) Respiratory distress
9) Severe depression
10) Unable to rise or unable to arouse
11) Diarrhea
12) Straining to defecate
13) Colic
14) Grinding the teeth
This a disease syndrome which should not be handled in the field and
needs to be
referred to a hospital. These foals require intensive care and close monitoring.
They may
require oxygen therapy, assisted ventilation, intravenous nutrition, and
constant nursing care.
Broad-spectrum antibiotics, nonsteroidal antiinflammatories, intravenous fluids,
drugs which
regulate blood flow, are among the medications required to sustain life.
RUPTURED BLADDER
The most common disorder of the bladder of the newborn foal is
rupture. Most
common in colts, it may occur in fillies. The clinical signs are usually present
within the first
two days of life and include straining to urinate, dysuria, depression, and
bilaterally symmetric
distension of the abdomen.
Surgery is the treatment of choice and the success rate is high is
performed within the
first 5 days of life. Emergency surgery usually is not required. The greatest
concern is the
hyperkalemic (high serum potassium) state the foal is in. Hyperkalemia can cause
profound
cardiac disease which can result in death.