Saving the Somnolent Foal

Neonatal maladjustment syndrome is a diagnosis of exclusion that must be reached quickly to save the foal. Learn about commonsense approaches to nursing “dummy foals” back to health.
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Saving the Somnolent Foal
Prompt and aggresssive treatment of maladjusted foals greatly increases the liklihood of swift and uneventful recoveries and minimizes their chances of developing life-threatening complications. | Photo: Anne M. Eberhardt/The Horse

A commonsense approach to nursing ‘dummy foals’ back to health

Dummy, barker, wanderer, sleeper. Neonatal encephalopathy. Hypoxic ischemic encephalopathy. Perinatal asphyxia. Neonatal maladjustment syndrome. No matter what you call the foal or the condition, it amounts to one sure thing: W-O-R-K.

“Affected foals can require intensive care if they are to be saved,” says Jen Gold, DVM, Dipl. ACVIM-LAIM, ACVECC, clinical associate professor at Washington State University, in Pullman. “This means round-the-clock care to keep them clean, dry, nourished, hydrated but not overhydrated, seizure-free, injury-free, avoid pressure sores if they are recumbent (lying down and unable to get up), and to frequently administer a medley of medications.”

In other words, caring for a critically ill foal will consume your time until the foal (hopefully) recovers. 

What Is a Dummy Foal?

Foals with neonatal maladjustment syndrome (NMS, also called maladjusted foals) suffer from an ill-defined noninfectious central nervous system dysfunction, explains Sally DeNotta, DVM, PhD, Dipl. ACVIM, clinical assistant professor of large animal medicine at the University of Florida, in Gainesville. Common signs of NMS include:

  • Loss of affinity for the mare and aimless wandering;
  • Excessive sleepiness and/or general dullness;
  • Lack of suckle reflex;
  • Stargazing, tongue protrusion, and stuporous behavior;
  • Seizures, either mild focal events and facial spasms or generalized muscle convulsions;
  • Apparent blindness;
  • Abnormal vocalization that sounds like barking; and
  • Irregular respiratory patterns.

Affected neonates (approximately 1-2% of live foals) usually exhibit the above-described clinical signs at or within a few days after an uneventful birth. Once a foal shows signs of neurologic abnormalities, your veterinarian should examine him and quickly rule out neurologic and other diseases affecting newborn foals, such as:

  • Bacterial meningitis (central nervous system infection);
  • Severe sepsis (systemic bacterial ­infection);
  • Equine herpesvirus-1 ­myeloencephalopathy;
  • Hepatoencephalopathy (abnormal liver function causing neurologic signs);
  • Metabolic and electrolyte disturbances;
  • Physical trauma (from a dystocia—a more difficult birth—or if the mare steps on the foal);
  • Congenital disorders (conditions they’re born with—hydrocephalus, for example, which is excess fluid around the brain);
  • Lavender foal syndrome, a genetic condition of Arabians; and
  • White muscle disease (resulting from inadequate consumption of selenium or vitamin E).

Once your veterinarian lands on an NMS diagnosis, treatment must be swift. You must also decide whether to refer your mare and foal to a clinic or take on the momentous task of caring for the foal on the farm.

“Supportive care is the most important part of managing dummy foals, especially because many of these foals may be septic, as well,” says Gold. “Early referral is always better than waiting. Signs that you need to refer include an inability or unwillingness to nurse, abnormal behavior, and obtundation (lethargy or lack of alertness).”

Yes, 24-hour intensive care is expensive; however, with correct supportive care, approximately 70-80% of affected foals recover completely and can go on to lead normal adult lives.

Necessary Support for Managing Affected Foals

All foals need full bloodwork to assess red and white blood cell counts, electrolytes, organ function (including kidney function), and, importantly, immunoglobulin G (IgG) levels to assess passive transfer of immunity (the transfer of infection-fighting antibodies from the mare’s first milk, or colostrum). Based on those clinical results, together with physical exam findings, your veterinarian might recommend implementing some, many, or all of the following treatments:

First and foremost, general nursing care.These measures keep the foal clean, dry, and ideally in a sternal position (lying down, but upright, with his chest against the ground) on a padded surface. Veterinary staff measures and assesses vital signs, hydration status, urine and fecal output, and the foal’s mentation frequently.

Nutritional support. Many maladjusted foals cannot stand and suckle on their own and might need frequent assistance standing and finding the udder, says DeNotta. More severely affected foals must be fed via a nasogastric tube until they are strong enough to suckle. Some foals might need intravenous nutrition in the form of parenteral nutrition, which is an injectable mixture of fats, vitamins, carbohydrates such as dextrose (sugar), and amino acids. 

Plasma administration to provide life-saving infection-fighting antibodies in cases of partial or complete failure of passive transfer. “IgG levels should be measured again 12-24 hours later and additional plasma administered as needed,” says Gold. “Carefully monitoring these foals for secondary infections is incredibly important. When diagnosed, aggressive use of broad-spectrum antibiotics is needed.”

Cautious fluid therapy to maintain hydration and improve blood flow to vital organs without contributing to overhydration and brain swelling. “If cerebral edema (brain swelling) is suspected, then agents designed to decrease the swelling can be administered,” says Gold. “These include mannitol, furosemide (Salix), and hypertonic saline.”

Seizure control. Veterinarians might use a variety of anticonvulsant medications to control seizures. “Protecting the foals from trauma during seizures may also be necessary,” says DeNotta.

Antioxidants such as vitamin E, ascorbic acid, and thiamine (a B vitamin) might help counteract the negative effects of scavenging free radicals, she says, which are highly charged, reactive forms of oxygen that contribute to mass destruction at a microscopic level. Vitamin E must be administered orally, whereas the other antioxidants can be injected intravenously or subcutaneously (beneath the skin). Some veterinarians might also prescribe dimethylsulfoxide (DMSO) for its free-radical-scavenging properties.

“Because reactive oxygen species are strongly believed to contribute to the worsening condition of dummy foals, antioxidants do theoretically appear to be useful,” Gold says. “DMSO has fallen out of favor for some veterinarians, however, with the preferential use of the other available antioxidants.”

Intravenous magnesium sulfate, which might bind to the neurotransmitter glutamate, which can be toxic at high levels and damages neurons (brain cells), to avoid a condition called excitotoxicity that can contribute to seizure activity.

Caffeine, administered orally or rectally, can stimulate the foal’s central nervous and respiratory systems, the latter of which is often depressed due to poorly functioning respiratory centers in the foal’s brain or other brain feedback. “Doxapram can also be used to stimulate respiration; however, if there is any question of cerebral hemorrhage, this medication should not be used because it can increase cerebral bleeding,” Gold warns.

Supplemental oxygen therapy, such as hyperbaric oxygen treatment, might be necessary if the foal is not breathing sufficiently to provide enough oxygen to tissues and organs.

Because many other organs in the foal’s body can be affected (most notably the kidneys, heart, and gastrointestinal tract), veterinarians must take care to correct associated abnormalities in addition to the neurologic aberrations.   

Controversial Treatments

The exact pathogenesis of NMS—how it develops, in other words—remains ­unclear. As you can see from the extensive list of therapies, treating affected foals can seem like a “kitchen sink” formulation where we administer anything that might help them recover. Some treatments, however, could be harmful.

“Multiple medications and therapies have fallen in and out of favor for the treatment of maladjusted foals over the last several decades,” says DeNotta. “Many were quite promising in theory but failed to demonstrate a benefit when critically evaluated in clinical trials. The one thing nearly all veterinarians agree upon, however, is that supportive care and protection from infection are the two most important aspects of treating foals with NMS.”

Take, for example, gastroprotectants. Stressed foals can easily develop gastric (stomach) ulcers. Administering medications to either prevent or treat gastric ulcers is fairly common practice; however, it can be detrimental to maladjusted foals. Gastroprotectants might even increase a foal’s risk of developing diarrhea from Clostridium or Salmonella, which can be life-threatening, says Gold. 

Many veterinarians also shy away from giving these foals non-steroidal anti-inflammatory drugs. “I am cautious using NSAIDs because the kidneys are still so susceptible to injury or may even be damaged,” says Gold.

DeNotta notes that corticosteroids are also contraindicated, as is ketamine, which can increase intracranial pressure and contribute to seizure activity. 

The Foal Squeeze: Pros and Cons

The Madigan foal squeeze is another technique that incites much discussion. Gently squeezing the foal using ropes for 20 minutes presumably induces a similar somnolent, or sleepy/drowsy, state as when the foal is in utero. This essentially artificially recreates the foal passing through the birth canal. Theoretically, when you remove the ropes, the foal’s neuroactive progestogens, or ­neurosteroids—which scientists believe maintain the foal in that in utero somnolent state—have a second chance to diminish so the foal can rouse appropriately and adjust to extrauterine life. In essence, the foal squeeze is a “do-over” of the foal’s birth.

In a 2017 study John Madigan, DVM, Dipl. ACVIM, ACAW, and colleagues from the University of California, Davis, found that performing this squeeze procedure hastened some dummy foals’ full recovery. They reported that they could treat foals successfully without medical therapy. Specifically, squeezed foals were 17.5 times more likely to recover within 24 hours than nonsqueezed dummy foals treated with traditional supportive care techniques. Further, 68% of foals treated with the squeeze alone recovered within 24 hours. While both the squeezed and nonsqueezed foals had impressive recovery rates—86% and 87%, respectively—the squeeze appeared to decrease recovery times.

Madigan et al. suggested that the squeeze can potentially avoid referral (in uncomplicated cases) and, therefore, reduce costs of nursing care.

The procedure, Gold warns, is not as benign as one might believe. “It works for some foals but not every dummy foal,” she says, adding that it can make the situation much worse if the foal has fractured ribs.

“The squeeze technique is a potential therapy, but horse owners should still always call their veterinarians at the first sign of a sick or abnormal foal,” DeNotta adds. “Further, owners should not attempt this on their own; it really ought to be performed by a veterinarian. My personal observation is the technique may benefit some foals, and so long as the procedure is done correctly and the foal does not have fractured ribs, I don’t see many downsides to trying it. If it doesn’t work, traditional medical (treatment) should not be delayed.”

What Causes NMS?

After your foal recovers, it might be time to reflect on what caused the ­condition in the first place. Several theories currently exist to explain how the syndrome develops, and no one theory seems to fit every case. This is why veterinarians prefer the term NMS over names that imply an underlying cause, including hypoxic-ischemic encephalopathy (HIE)—one of the traditional prevailing theories.

With HIE, hypoxic-ischemic events occur followed by reperfusion injury. This means that some event around the time of birth causes diminished blood (and therefore oxygen) supply to the foal’s brain and other vital organs. In the face of reduced blood flow, the body diverts the remaining blood to vital organs, including the brain. In many instances, the brain doesn’t receive enough blood, and the neurons shift their metabolic pathways in an attempt to provide an alternate source of energy. These changes result in neuronal swelling and the production of inflammatory mediators. In addition, that potentially toxic neurotransmitter we mentioned earlier, glutamate, accumulates within neurons.   

Once oxygen-rich blood begins to flow back to the brain (reperfusion occurs), a second wave of cell death occurs due to the widespread release of free radicals and inflammatory mediators.

This process might be to blame in some maladjusted foals, particularly those with known risk factors for hypoxic-ischemia, such as foals born to mares affected by placentitis (placental inflammation), dystocia, or premature placental separation (often called “red bag” deliveries). This theory, however, doesn’t fit all cases, particularly foals born uneventfully that appear normal for the first few days of life.

“Many maladjusted foals do not have any discernible risk factors for hypoxic brain injury during gestation or birth, and true injury from oxygen deprivation likely represents only a portion of the maladjusted foals we see,” says DeNotta. “In many cases, we don’t know what caused the foal to be maladjusted.” 

A more recently introduced theory that might explain NMS in most (but again, not all) foals—and the one the Madigan method is based around—involves altered neurosteroids. Again, neurosteroids play a role in promoting the sleeplike state of consciousness in utero. This reduces fetal activity and protects the mare from the movements of her large, leggy passenger.

In normal newborn foals neurosteroid levels decrease over several days to facilitate the transition to extrauterine life, in which the foal is alert, active, and able to nurse.

“It’s thought that persistence of these neuroactive progestogens can cause the ‘sleepy foal’ behavior and obtundation characteristic of maladjusted foals,” says DeNotta.   

More research regarding the mechanisms contributing to the development of NMS will help veterinarians prevent the condition and establish more targeted treatments to increase survival rates.

Take-Home Message

Prompt and aggressive treatment of maladjusted foals greatly increases the likelihood of swift and uneventful recoveries and minimizes their chances of developing life-threatening complications such as sepsis, says DeNotta. While the intensive care required to nurse foals back to health can be costly, the fact that most foals recover fully and go on to live normal, healthy lives might make the expense and effort well worth it in the long run.

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Written by:

Stacey Oke, MSc, DVM, is a practicing veterinarian and freelance medical writer and editor. She is interested in both large and small animals, as well as complementary and alternative medicine. Since 2005, she’s worked as a research consultant for nutritional supplement companies, assisted physicians and veterinarians in publishing research articles and textbooks, and written for a number of educational magazines and websites.

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