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Common Illnesses of Newborn Foals

What you need to know.

Foals can face a range of health issues, from failure of passive transfer to neonatal encephalopathy.

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Fortunately, most newborn foals hit the ground running, almost literally. While there are many foal veterinary problems, a few are more common than others. Interestingly, one of them has fascinating parallels with human autism.

Warning Signs 

Some seemingly normal pregnancies result in abnormal foals, but most problem foals arise from high-risk pregnancies. Conditions that can lead to problems in new foals include a mare’s illness during gestation, inflammation of the placenta or premature placental separation—so-called “red bag” delivery—twin pregnancies, dystocia, prematurity and hypothermia. Unsanitary conditions in the foaling environment can put newborns and mares at risk for post-partum issues.

Once Baby Hits the Ground 

Normal foals should get up in less than an hour. When they do rise, they should be active and look to interact with the mare and nurse almost immediately.

The first sign that a veterinarian should be called is when a foal doesn’t act normally. But even if a foal seems healthy, she should be examined to ensure no underlying problems.

Failure of Passive Transfer (FPT) 

Probably the most common abnormality of newborn foals is the failure to acquire adequate passive immunity through the mare’s colostrum, a problem that occurs in as many as 20 percent of cases. Because foals are born immunologically naïve, passive antibody transfer from the mare’s first milk is required to provide immune protection during the first weeks of life. Without that protection, foals become susceptible to neonatal infections within the first week.

FPT has a variety of causes, including poor-quality colostrum, a failure to ingest adequate colostrum and failure to absorb ingested colostrum. The first step in such cases is to ensure that the foal’s serum IgG levels are adequate. There are several ways to measure IgG levels—usually by no later than 24 hours post-partum—and levels below 400 mg/dl are generally considered FPT.

Some foals do well despite FPT, but most with low serum IgG levels are treated. If a foal is less than 12 hours old, fresh or frozen colostrum administered by nasogastric tube is an effective treatment. However, by the time a foal is 20 hours old, less than 1 percent of orally administered immunoglobulins can be absorbed. After this time, foals are usually given intravenous therapy with normal or hyper-immune plasma. However, these are less desirable treatment options because colostrum has many beneficial factors besides immunoglobulins.

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Many breeders elect to vaccinate pregnant mares one month before foaling to try to boost colostral Ig levels. In larger breeding operations, frozen colostrum may be kept on hand so that interventions can begin early.

Neonatal Infections 

Neonatal sepsis, a systemic response to infection, is the most common cause of death in newborn foals. Most neonatal infections are bacterial in origin and can enter the foal by ingestion, through the respiratory tract, via the umbilicus or across the placenta.

The first signs of neonatal sepsis are abnormal behavior, usually occurring seven to 10 days after birth. Sick foals stop nursing, become weak, develop rapid heart and respiration rates, have fever, show signs of shock in the sclera, mucous membranes of the mouth and ears, or at the coronary band, and rapidly progress to multiorgan system failure.

While there are usually multiple hematological abnormalities, including low white blood cell count and increased lactate levels, veterinarians may not have time to determine the exact cause before instituting treatment. Care typically includes antibiotics, fluids, nutritional support, intravenous plasma and other supportive care.

Preventing sepsis may be difficult, but interventions such as vaccinating the mare, ensuring a clean foaling environment, washing the mare’s udder before nursing, cleaning and caring for the umbilicus, and ensuring colostral intake are critical.

Neonatal Encephalopathy 

One of the more perplexing problems with newborn foals typically occurs within 36 hours post-partum. The condition has had many names in the past, including dummy foal syndrome and neonatal maladjustment syndrome.

Signs of neonatal encephalopathy vary but can include loss of suckle reflex, wandering, lack of awareness, abnormal breathing patterns and seizures. Treatment has included a variety of supportive interventions as well as antiseizure medication. With intensive treatment, usually for one to two weeks, many of these foals will fully recover.

In the past, veterinarians asserted that foals developed neonatal encephalopathy because of a lack of oxygen in the birth canal. However, that scenario would be expected to cause permanent neurological problems, and foals suffering from neonatal encephalopathy typically recover.

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Research done at the University of California, Davis, suggests that at least some of these foals may develop problems because of failure of the mechanisms involved in the post-foaling transition to consciousness. These foals have interesting similarities to autistic human children.

In utero, neurochemicals make the foal lie still as it passes through the birth canal, but at some point before the baby enters the outside world, a biochemical change signals the foal to look for its mother, nurse and start moving. UC Davis researchers believe that pressure from the birth process itself is an important trigger to a normal existence outside the mare.

Signs of neonatal encephalopathy may be reduced in many foals by using a rope harness to gently squeeze the foal, mimicking the pressures of the birth canal.

For more information on this important research, see the U.C. Davis website here.

You can also watch the video below. "UC Davis equine veterinarians, tracking the cause of a set of bizarre and sometimes lethal behaviors in newborn horses, suspect the disorder is caused by the foals’ failure to fully transition from the womb to the conscious world. They’ve discovered a simple treatment for the syndrome and are now working with colleagues in human medicine to explore possible links to autism in children," researchers write in the video description.

Meconium Impactions 

Meconium is the dark green substance forming a foal’s first feces. Impactions of the meconium are the most common cause of abdominal pain and swelling in newborns.

The condition is usually seen in the first few hours of life as affected foals strain to defecate, swish their tails, become depressed, roll and stop nursing. Diagnosis is often based on history alone but may require ultrasound or contrast radiography. Many meconium impactions resolve with enemas—especially acetylcystine enemas, which have a high success rate—but also may require analgesic treatment, fluids and other types of supportive care. Foals typically do well after the impaction resolves.

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Little foals can have big problems. Knowing how to manage these conditions might mean the difference between life and death.


Dr. Ramey, an author, lecturer and Southern California equine practitioner, specializes in the care and treatment of sport and pleasure horses. His website is www.doctorramey.com. He is a 1983 graduate of the Colorado State University College of Veterinary Medicine and Biomedical Sciences. 

Originally published in the March 2016 issue of Veterinary Practice News. Did you enjoy this article? Then subscribe today! 

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