Little is known about what causes pharyngeal dysfunction—a defect in the muscle or nerve functions of the pharynx—in newborn foals. This important area of anatomy, where the paths for air and food or liquids intersect, was the topic of interest recently for a team of researchers who completed a study on the prognosis of foals with dysphagia (difficulty swallowing) associated with pharyngeal dysfunction. The good news? Many of these foals went on to live healthy and productive lives.
In the study, a team of researchers led by Susan Holcombe, VMD, MS, PhD, Dipl. ACVS, ACVECC, a professor at Michigan State University (MSU) College of Veterinary Medicine, reviewed medical records of 16 neonatal foals admitted to MSU, The Ohio State University College of Veterinary Medicine, or Rood & Riddle Equine Hospital, in Lexington, Ky., from 2000 to 2010. Foals included in the study exhibited a normal to strong suckle, showed dysphagia (milk at the nostrils and/or within the trachea after nursing), and underwent an endoscopic examination of the airway.
During hospital admission the 10 colts and six fillies received antimicrobials to treat or prevent lung infections. Ten received nutrition through a nasogastric tube for one to 14 days before nursing. One of those foals then was fed from a bucket for three days to limit milk volume and prevent milk from running down the trachea. The foal then was returned to nursing.
Five foals were not fed with a feeding tube: Three were removed from the mares for 24 hours and given intravenous infusions of fluids and dextrose before being reintroduced to nurse successfully within two days, and two stayed on the mares because of the owners’ concerns.
One of the latter foals was euthanized due to pneumonia. Attending veterinarians discharged the remaining 15 after an average of seven days.
Follow-up records that spanned one to five years from hospital discharge were available for 14 of the 15 foals. Two were ultimately euthanized due to debilitating pneumonia, while 12 showed no evidence of dysphagia or pneumonia. Reports indicate the foals went on to a variety of athletic or nonathletic careers; however, two horses later showed evidence of left-sided recurrent laryngeal neuropathy, or “roaring.”
Researchers concluded that while dysphagia resulting from pharyngeal dysfunction can occur in newborn foals, most could nurse successfully within two weeks. The team considered the dysfunction resolved at that point.
“Foals with dysphagia were previously given a guarded prognosis,” said Holcombe. “We learned that with time and supportive care--including enteral (via the gastrointestinal tract)nutrition, airway protection, and antibiotics--many of these foals will eventually swallow normally and have successful careers.”
Researchers said owners might want to consider a physical therapy for affected foals that is similar to that used for human newborns with pharyngeal dysfunction–suckling on a pacifier. Milking the mare, so there’s little to no milk left to affect the foal,and then allowing the foal to suckle for short bursts could also strengthen the foal’s muscles and improve his coordination, the team added.
If a foal begins to show signs of dysphagia—which can include ptyalism (excessive salivation), gagging, nasal discharge, coughing (as some of the material may be aspirated into lungs resulting in acute aspiration pneumonia) and exhibiting forceful attempts to swallow—it's advisable to consult a veterinarian to begin treatment. Additionally, it's important to work with a veterinarian to assure the foal receives proper nutrition while battling pharyngeal dysfunction.
Disclaimer: Seek the advice of a qualified veterinarian before proceeding with any diagnosis, treatment, or therapy.