Oxygen Deprivation in Newborn Foals

In most cases mares give birth quickly and without complications. The foal stands and nurses within an hour or two and a few days later is following the mare around the pasture and snoozing in the sunshine. Sometimes however complications just before during or after birth can result in a decreased oxygen supply to the foals brain. Various terms such as hypoxic ischemic encephalopathy or neonatal maladjustment syndrome have been used to describe the manifestations of oxygen deprivation. Around the barn managers refer to these foals as wanderers sleepers barkers or dummy foals.

Anything that reduces the amount of oxygen reaching the brain can rapidly affect brain cell function. The problem can be depleted blood flow normal blood flow with depleted oxygen or a combination of these factors. One reason for interrupted oxygen supply before birth might be premature separation of the placenta from the uterus. Uterine infection twin pregnancy and fescue toxicosis are other risk factors. If the birth is difficult and delivery is delayed compression of the umbilical cord may reduce the foals blood supply. When the umbilical cord is broken soon after delivery the foals heart and lungs must assume circulatory functions that were previously supplied by the mare. Any delay in this process can cause a drop in the amount of oxygen that is delivered to the foals brain. When blood supply is restricted and again when it is restored chemical changes lead to cell death swelling of brain tissues and impaired neurologic function. Other organs in the respiratory and gastrointestinal systems are frequently affected if oxygen deprivation is severe or prolonged.
Recognizing Oxygen Deprivation
The various names for this condition are descriptive of an affected foals behaviour. Some foals dont seem to recognize the mare and are unable to nurse. They may wander around the stall getting stuck in a corner and being unable to find their way out. Others slip into frequent periods of deep sleep have seizures or make strange barking vocalizations. These signs may be present shortly after birth but it is also common for a newborn foal to seem completely normal and then begin to exhibit signs in a day or two. Abnormal behaviour that begins as long as a week after birth may be due to an oxygen deficit at the time of foaling.
Newborn foals may be affected by a number of problems several of which might be mistaken for oxygen deprivation. If