What is normal in the newborn foal?

History

The first part of any neonatal examination is a thorough history. This is often acquired orally at the farm, over the phone or in the form of a foaling record chart.

Important details include:

• Time of foaling,
• Duration of foaling,
• Any difficulties during foaling.
• Was the foaling observed, if not where was the foal in relation to the mare when it was found, alone or nearby. Was the foal wet indicating a recent birth or was it dry?
• Has the foal met normal post-delivery milestones?
• Has the foal nursed? Did the mare drip milk before foaling?
• Was the colostrum quality tested?

The general history of the mare is also important:

• Did she carry to term?
• Is she multiparous or is she a maiden foaler?
• Has she had problems with previous pregnancies or foals?
• History or evidence of placentitis (examination of the placenta).
• Vaccination status of the mare.
• Was the placenta passed in an appropriate time frame (<3hours) Normal developmental milestones and timeframes 

Clinical examination of the newborn foal should always begin at a distance, with observation of behaviour, respiratory rate and musculoskeletal abnormalities. Normal foals will nurse for short periods, multiple times each hour and will follow the mare closely. Changes in bahaviour, including loss of affinity for the dam or abnormal nursing behaviour can be a sign of Hypoxic-Ischaemic encephalopathy (HIE) or sepsis. Respiratory rate and character should be assessed both when the foal is resting and when ambulating around the stall. Signs of prematurity or dysmaturity should be evaluated including small size for breed and gestational age, a domed forehead, floppy ears and a silky haircoat. Limb laxity can also be a sign of prematurity. Many congenital abnormalities are also obvious from a distance while others may be suspected and required a closer examination.

Clinical examination should be systematic and include all body systems.

Mucous membranes and sclera may show the presence of ecchymotic hemorrhages caused by the pressure of passage through the birth canal and be mildly injected compared with adults. The capillary refill time is similar to adults.

A normal cardiac sinus rhythm or sinus arrhythmia is auscultated. It is common to hear a systolic murmur (point of maximum intensity at the left heart base) for a few days after birth. Murmurs that persist longer should be evaluated further.

The normal foal’s respiratory rate and effort should decrease over the course of the first day of life, and its heart rate should increase after a few minutes. Foals should urinate within the first 24 hours of life, and urine should become progressively more dilute as they begin to consume a liquid diet.

Many normal foals are born with a mild degree of carpal and fetlock valgus in their front limbs and slight varus in their hind fetlocks. This condition typically resolves as they grow.

Foals should pass meconium, the first faeces, within 12 to 24 hours. Meconium is dark brown to tan and may be hard or pasty. Subsequent milk faeces are yellow tan and typically softer in consistency.

Neonates lack a menace response, as this is a learned behaviour that will develop at a few weeks of life. Stimulation (auditory or visual) often results in exaggerated, jerky head movements. The neonatal foal’s primary behaviour should be directed toward maintaining close contact with its dam.

Foals can be bradycardic at birth; the heart rate should increase relatively quickly to normal values. Persistent bradycardia can be caused by hypoxia, hypoglycaemia, and hypothermia. Oxygen supplementation should be instituted. A continuous intravenous (IV) infusion of dextrose is recommended (see section on fluid therapy) if glucose monitoring is not available. Bolus therapy with glucose-containing fluids is not recommended, as hyperglycaemia has deleterious effects. If bolus therapy is unavoidable, dextrose should be added to an isotonic crystalloid at a low percent (0.5% solution = 10 mL 50% glucose in 1-L crystalloids). If a foal is mildly hypothermic, it is recommended to allow slow, passive warming (cover the foal and keep in a dry, warm area out of the wind), as hypothermia is protective against hypoxic brain injury.1 With more severe hypothermia, active warming is recommended and is best done by infusion of warmed IV fluids. The use of external heat sources is controversial as the resultant peripheral vasodilation can cause a reflex drop in core temperatures as cold blood flows centrally from the periphery. [...]