A healthy newborn foal should be able to sit on its chest within a few minutes of birth and stand within 1 hour. An effective suckle reflex should be present within 20-30 minutes and the foal is expected to stand and nurse from the mare within 2 hours. Compromised foals may not meet these targets and require immediate intervention. Heart rate and respiratory rate are two useful indicators of neonatal compromise in the immediate post foaling period. If either is persistently increased or decreased, further evaluation is necessary. Rectal temperature is not a reliable indicator of infection in the neonate. Indeed, premature and septic foals can have low temperatures due to a poor ability to control their body temperature.
General Appearance
Healthy foals should be bright and inquisitive. When woken, they should rouse easily, stretch and nurse. A foal displaying low head carriage, drooping ears and which exhibits a tendency to fall asleep while standing is showing signs of weakness. Other signs of a sick foal include increased time lying down, less time nursing and standing under the mare but not nursing. Skin abrasions associated with increased recumbency and attempts to stand are often present over the bony protuberances. Other tell-tale signs may be engorgement of the mare’s udder and dried milk present on the mare’s legs and foal’s head. A lack of affinity for the mare in an otherwise bright foal may indicate neonatal syndrome (colloquially known as a ‘dummy foal’) or meconium impaction. Inability to nurse can be associated with neurological dysfunction, illness or oral and other physical problems.
Immature foals typically present with floppy ears, a silky hair coat, a slightly domed forehead and increased laxity of the joints and tendons. The term premature should be used in reference to foals that are born before 340 days of gestation and show signs of immaturity. Foals that are born at term but remain physically immature are termed dysmature. Post-mature foals are born at greater than 356 days of gestation.
Skin abrasions may first appear as small areas of increased moisture around the orbits of the eye and on the prominences of the hips, lateral stifle, hocks and coronary bands. They may represent increased periods in recumbency or attempts to stand.
Assess the elbows, lower abdomen, umbilicus and the area under the tail for any signs of oedema or swelling.
Skin tenting may be used as an indicator of hydration status but is less reliable than in the adult. Sunken eyes may suggest dehydration but can also be the result of growth retardation in the uterus.
Cardiovascular System
Mucous membranes should be pink, moist and have a capillary refill time of 1-2 seconds after blanching of the gums. Reddened mucous membranes accompanied by increased prominence of blood vessels in the sclera (white of the eye) and reddened coronary bands are typical of a foal in early sepsis. This may progress to darkening of the mucous membranes with a delay in refill time as sepsis progresses. Yellowing, pinpoint haemorrhage, pallor or grey-blue cyanotic mucous membranes all indicate serious dyfunction that warrants veterinary attention immediately.
The heart rate of a foal at birth is 36-40 beats per minute. As the foal attempts to stand this will increase to 120-150 beats per minute, before stabilising at around 80-100 beats per minute over the first week of life. Persistently high or low heart rates in the neonate indicate compromised health and the foal should be examined by a veterinarian. Equally, a transient (temporary) arrhythmia is not uncommon in the neonate, but any persistent arrhythmia needs investigation.
Murmurs are easily heard in the newborn foal and are relatively common as the circulatory system matures and switches over from the foetal set-up. This process may take up to 7 days to occur. In foals compromised by other illness, additional support may be required through this period to achieve adequate oxygenation of the tissues and organs. Persistent loud murmurs that remain after 7 days of age or those that are accompanied by signs of cardiac disease e.g. poor growth, poor colouration and lethargy need to be evaluated further.
No jugular pulse should be visible in a foal. Extremities should not be cold to the touch; this is often associated with poor tissue perfusion. Weak pulses on palpation may indicate hypotension and a need for fluids.
Respiratory System
The respiratory rate of a newborn foal is 60-80 breaths per minute, decreasing to 30 breaths per minute within 1 hour of birth. There are many conditions that can lead to an increased respiratory rate and they can be pulmonary or non-pulmonary in origin. It is normal for a foal to have irregular periods of breathing while asleep, but when awake, the breathing pattern should be regular. Any sign of increased respiratory effort is also of concern, as it can be an early indicator of impending respiratory failure. Lung sounds are not a reliable indicator of lung disease in the newborn foal.
The chest should always be gently palpated for the presence of any fractured ribs. A crackling sensation (crepitus) may be felt, or sometimes just a faint ‘clicking’ noise. Affected foals may grunt with expiration and prefer to lie on the unaffected side.
Gastrointestinal System
Examine the mouth for the presence of a cleft palate, parrot mouth and other malocclusion of the bite and jaw. The tongue should be inspected for the presence of any candida infection. If the tongue is protruding or hanging out of the mouth, this may indicate mild neonatal syndrome.
Make sure the foal has passed its meconium. A foal that has meconium impaction may go ‘off the suck’ or be seen frequently tail twitching and in obvious discomfort.
Owners of coloured horses should make themselves aware of ‘lethal white foal disease’, in which portions of the gastrointestinal tract may fail to develop.
Neurological System
Critically ill neonates are often depressed, recumbent and unable to suckle. This may be due to primary neurological disease but is more commonly seen secondary to other underlying disease. Those with Arabs should be aware of the existence of breed related congenital abnormalities such as cerebellar abiotrophy and occipito-atlantal malformations.
It is best to first examine the foal from afar, observing its interactions with the mare. Consider its alertness, ability to nurse and head carriage. Make note of any hyper-responsiveness to stimuli, head tilt, circling or deviations in the body which would merit concern.
The suckle reflex requires the co-ordinated effort of several anatomical structures and nerves. A foal with neck pain may have a good tongue curl, strong lip seal and co-ordinated suckle, but be unable to nurse because of the neck position required. Difficulty or inability to swallow is generally recognised by regurgitation of milk through the nose or mouth. Cleft palate is the first cause to rule out, however it is a far less common cause of this condition than other abnormalities of the larynx and pharynx.
Urogenital System
Evaluate the external genitalia and umbilicus. In colt foals, preputial oedema can result from straining due to a meconium impaction, scrotal hernia or fluid overload. Some colts may not extend their penis fully to urinate in the first week of life. In fillies, oedema may be subtly appreciated in the area under the tail. Vulval lips should be examined for any colour changes indicative of systemic disease.
The umbilicus should be palpated for swellings associated with haematoma, urine leakage or herniation. The first urine produced by the normal foal is concentrated and occurs an average of 6 hours after birth in colts and 11 hours after birth in fillies. After the first urination, the urine should become dilute and output should be approximately 300ml/hr for a 50kg foal. Most foals will urinate frequently during the day, generally just after standing or nursing. Decreased output may reflect renal failure, hypotension, dehydration or urinary tract disturbances. Slow, painful urination can be associated with urinary tract infections and ruptured bladders.
Musculoskeletal System
Evaluate the foal for evidence of maturity, congenital abnormalities, birth trauma, angular limb deformity or septic joints. Begin at the head and proceed along the foal in a systematic manner. If the eponychium (‘snowshoes’) are still present, it suggests that the foal has not stood or only stood for a short period of time after birth. Examine the skull for any signs of a domed forehead, wry nose or cleft palate. Ribs can easily be fractured during foaling, particularly in a difficult presentation where assistance was required. Tendon contracture or laxity should be assessed. Palpate all joints for swelling or heat. Any abnormalities should be assumed to be infectious until proven otherwise. Premature foals should have x-rays taken to ensure that the cuboidal bones of the hocks and knees are appropriately ossified and able to support the weight of the foal.
Eyes
The corneas should be clean with no excessive tears or discharge. The most common cause of corneal ulceration and oedema is entropion. This term describes a condition in which the eyelid margin rolls inward, such that the eyelashes can rub on the surface of the eye. It can be associated with prematurity, dehydration, lack of periorbital fat or generalised muscle weakness. Treatment involves the placement of sutures to evert the eyelid, while the underlying cause is corrected.
Birth trauma may cause haemorrhage or reddening of the conjunctiva or sclera, such foals should be closely monitored for the development of any other complications. Sepsis can also cause changes within the eye including uveitis. Cataracts are the most common congenital eye disorder in the foal.