EQUINE VETERINARY EDUCATION / AE / FEBRUARY 2018


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Nutrition Neonates are born with limited energy reserves and rely on the ingestion of colostrum both for energy and the passive transfer of antibodies. Failure to nurse can lead to hypoglycaemia, dehydration, declining body temperature and depression that can contribute to the lack of suckle response and udder seeking behaviour. The normal foal nurses 5–7 times per hour, in bouts of about 2 min each. If this activity is interrupted or does not occur, the foal can rapidly become weak and fail to nurse in as little as 2–4 h after birth. Mare behaviour can be a contributing factor, as nervous or maiden mares may not allow nursing. The practitioner’s first goal is to determine if the foal can


achieve adequate nutritional intake and, if not, what can be done to address the lack of nutritional intake. Foals with weak suckle response may require nutritional supplementation of milk or milk replacer. To ensure that the correct amounts of milk are delivered, an in-dwelling naso-oesophageal tube can be used. The correct positioning of the tube in the oesophagus must be confirmed prior to the administration of milk. Endoscopy and radiography have been recommended, but the author has found the palpation of the tube above the trachea to be a reliable method of determining correct placement of the tube. Small-bore tubes can remain in the stomach or be retracted into the distal oesophagus. The advantage to leaving the tube in the stomach is the tube can be used to check for reflux before each feeding without the need to reposition the tube. The disadvantage of leaving the tube in the stomach is the risk of milk tracking out of the stomach. The small diameter, commercially available tubes (Nasogastric feeding tube with stylet)2 minimise the risk of reflux if left in the stomach (Buechner-Maxwell 2012). The position of the tube at the nostril should be marked, and the tube securely attached to the nostril. To prevent kinking, the tube may either be taped to a tongue depressor or inserted through the provided nose piece and taped to the muzzle of the foal as an effective method to secure the tube. Care must be taken to ensure the foal can open its mouth sufficiently to nurse. In ambulatory practice, small feeding tubes have proven


invaluable for foals that need supplemental nutrition and are easy to use by farm personnel with minimal training. A laminated instruction sheet with explicit feeding directions should be provided (Table 1). Cleanliness should be emphasised to personnel so as not to overburden the foal’s gastrointestinal tract with bacteria. The mare should be milked every 2–4 h, and the milk should be filtered through gauze prior to being administered. Excess milk should be refrigerated or discarded if production exceeds needs of the foal. Refrigerated milk will need to be warmed before administration, and all supplies should be thoroughly cleaned between feedings. Reduced milk production or letdown is common in mares hospitalised with sick foals and can be managed with domperidone (1.1 mg/kg bwt per os q. 24 h) or oxytocin (1–3 iu/450 kg bwt i.v.), respectively. Normal foals usually consume up to 25% of their


bodyweight as milk; however, recent studies would suggest that requirements for sick neonates may be reduced by 50% (Paradis 2001). Overfeeding increases the risk of hyperglycaemia, hypercapnia and azotaemia (Klein et al. 1998). Enteral nutrition is the preferred method of nutritional support, and the enterocytes require local nutrition for normal development even in foals that do not tolerate


TABLE 1: Instructions for maintaining indwelling feeding tube


1 The foal must be standing or in sternal position with the head at a level above the stomach before feeding.


2 Measure the size of the abdomen. If abdomen is enlarging over 3 consecutive feeding without signs of abdominal discomfort, give half of indicated feeding and recheck in 2h.


3 Check tube position. A mark was made on the tube adjacent to the nostril. If the mark has moved away from the nostril, do not administer anything through the tube and call your veterinarian.


4 Wipe off the end of the tube with alcohol, uncap tube, clear tube with a small amount of air, and apply gentle suction with syringe. If >40 ml of reflux is obtained, delay next feeding for 1–2h.


5 Flush tube with 20 ml of water. If tube is patent and patient is comfortable proceed to feeding.


6 All milk must be given by gravity flow. 7 After feeding, flush tube with 20–30 ml of water. 8 Use 20 ml of air to remove fluid from tube, clean and dry tube end, and cap tube.


significant amounts of enteral feeding (Rothman et al. 1985). If nutritional supplementation is necessary, it is best to start by giving about 5–7% of bodyweight the first day divided into 12 equal feedings. Once the foal is more stable, the amount of milk or milk replacer may be gradually increased. Current estimates suggest that administration of 10% of bodyweight as milk or milk replacer is sufficient to meet the energy need of the sick neonate (Buechner- Maxwell 2012). Because gastric motility can be reduced or absent in ill


foals, the caregiver and clinician must monitor for ileus and bloating. Abdominal distention can be monitored by repeated measurement at a marked location, and ultrasonography can be used to assess intestinal motility. If bloating is accompanied by abdominal pain or reflux, the foal should be assessed by the veterinarian, and the indwelling tube should be removed and replaced by a tube of sufficient diameter to remove accumulated reflux. Feeding should be discontinued until bloating resolves. Faecal consistency of foals receiving milk replacer should be carefully monitored as constipation or diarrhoea may occur. If constipation is evident, hydration status should be reassessed and increased fluid administration considered. Foal attendants should be instructed to record frequency of urination, in addition to catching periodic samples to assess hydration status. Urine specific gravity <1.012 is evidence of adequate hydration, which can be checked by the veterinarian using a refractometer. Diarrhoea may point to sepsis, concurrent bacterial or viral disease, increased bacterial contamination during feeding, or too concentrated milk replacer formulation and should prompt careful evaluation of the foal. Most foals that require nutritional support in the field show


a positive response after 1–2 days and resume suckling or learn to bucket feed. Foals that are not taking in adequate nutrition are at risk of developing dehydration and hypoglycaemia. These factors must be addressed with intravenous fluid therapy. Foals that are ill enough to require more prolonged nutritional support frequently are intolerant of enteral feeding and require more intensive care than can easily be delivered in the field.


© 2016 EVJ Ltd


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