Foal Health: Recognizing Neonatal Maladjustment Syndrome

A mother horse and foal

The anticipation of the birth of a foal is a moment of hope and excitement for horse owners. This moment can be overshadowed, however, if the mare or foal experiences health problems during the pregnancy.

Dr. Amanda Trimble, a clinical assistant professor of equine internal medicine at the Texas A&M School of Veterinary Medicine and Biomedical Sciences, provides horse owners with the knowledge to recognize the signs and risk factors associated with neonatal maladjustment syndrome, a rare, yet potentially serious condition that can develop during pregnancy and impact the health of foals.

Physical, Behavioral Signs

Neonatal maladjustment syndrome (NMS) — also known as neonatal encephalopathy (NE), perinatal asphyxia syndrome (PAS), or hypoxic-ischemic encephalopathy (HIE) — is a condition in which a foal experiences neurological abnormalities during or shortly after birth. These foals are commonly referred to as “dummy foals.”

“NMS affects a small percentage of newborn foals, roughly 1-2% of all equine births,” Trimble said. “Some foals may be born normally, with no issues reported during the pregnancy, birth, or post-birth, and still develop signs within 24-48 hours.”

Some of the most common signs that Trimble recommends owners watch out for include:

  • Lethargy, or difficulty waking up
  • Weakness
  • Tongue sticking out
  • Unable to suckle or nurse
  • Uncoordinated nursing, difficulty swallowing, or inability to swallow milk
  • Inability to find the udder, instead attempting to nurse on other parts of the mare or other objects
  • No affinity for following the mare
  • Unaware of surroundings or “wandering”
  • Seizures
  • Odd vocalizations such as “barking”
  • Abnormal breathing patterns
  • Digestive problems that result from nerves or muscles in the gut being uncoordinated, also known as GI motility

Knowing the specific signs of NMS can help owners recognize it and seek veterinary assistance promptly, as some NMS signs are similar to or may be present with other neonatal conditions such as sepsis, a life-threatening infection; pneumonia; or patent urachus, an improperly closed belly button.

Risk Factors

Foals can be born abnormally and display signs immediately after birth. There are several ways a pregnancy or birth can be considered abnormal, which can increase the risk of NMS. Some of these, according to Trimble, include:

  • Dystocia, or a birth that requires assistance, most commonly due to improper positioning of the foal that prevents it from passing through the birth canal
  • Problems involving the placenta including placental separation (known as Red Bag Delivery) or placentitis (infection of the placenta)
  • Induced labor
  • C-section deliveries
  • Premature births
  • Severe illness in the mare while pregnant
  • Fescue toxicity, a condition caused by eating tall fescue grass that is infected with fungus
  • Meconium aspiration, or when a newborn has trouble breathing after inhaling meconium (their first feces) either in the womb or shortly after birth
  • Twin pregnancy
  • Umbilical cord compression

Regardless of when NMS develops, prompt veterinary care is essential for a foal’s well-being, so owners should be aware of the risk factors and seek professional assistance early to reduce the likelihood of an abnormal birth that could lead to NMS.

Pet Talk is a service of the School of Veterinary Medicine & Biomedical Sciences, Texas A&M University. Stories can be viewed on the web at Suggestions for future topics may be directed to

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