An introduction is in order. Dr Terry Gerros is an Equine Internal Medicine specialist that we came to know and rely on when he was at the Oregon State University Veterinary School. Terry’s entire veterinary career has been involved with horses. Terry grew up in the Kentucky thoroughbred country and was in private practice at one of the well known farms in Lexington prior to returning to school to further his veterinary education. He then moved to Oregon State University and taught Internal Medicine at the Vet School for 9 years. Since then he has again returned to private practice restricted specifically to equines. The information that follows was published by Dr. Gerros and was graciously provided to us for posting for the readers of our website. It was originally written for practitioners so some of the words are pretty technical but if you can bounce over them there is a wealth of great information related to foals and critical care issues.
Terry C. Gerros, DVM, MS, Diplomate, ACVIM.
Assistant Professor, Large Animal Medicine
Oregon State University
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.
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
1. Normal respiratory and cardiac rhythm Within 1 minute
2. Righting reflexes established Within 5 minutes
3. Sucking reflex established Within 30 minutes
3. Attempts to stand Within 60-120 minutes
4. Ability to stand unassisted Within 60-180 minutes
5. 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 a lot 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
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
Meconium staining, Placental abnormalities, Placentitis, Twins, Orphan, Inadequate colostral intake,
Immaturity/prematurely, Exposure to infectious disease, Trauma
SPECIFIC DISEASES OF THE EQUINE NEONATE
It should be obvious to you that we can not possibly go through 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.
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.
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. A 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 blood type. 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.
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.
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:
2. Ataxia (uncoordinated)
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.
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 multi-systemic disease and many of the patients concurrently have ongoing sepsis, failure of passive transfer, enteritis, ulcers, etc.
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
8. Severe depression
10. Unable to rise or unable to arouse
12. Straining to defecate
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, non-steroidal anti-inflammatories, intravenous fluids, drugs which regulate blood flow, are among the medications required to sustain life.
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.
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.