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EQUINE VETERINARY EDUCATION / AE / FEBRUARY 2018


digest than cow’s milk. Most foals will accept a goat milk diet and exhibit satisfactory growth. A normal, healthy neonatal foal consumes roughly 15% of


bodyweight as milk in the first 24 h. By 5 weeks of age foals spend more than 20% of their time grazing or eating nonmilk foods (McKenzie and Geor 2009). As the foal matures the capacity for fibre digestion increases and by 6 months of age the foal is receiving less than 30% of the total nutritional requirement in the form of milk. Foals are born without bacteria in the gastrointestinal tract, but colonisation begins rapidly with a mature microbial community present by the sixth week of life (Earing et al. 2012). Overall, the timeline of the microbial establishment of the gastrointestinal tract is consistent with the time at which plant-based feeds become important in the diet of the foal. As hindgut function increases a shift in the primary energy substrate also occurs from ingested carbohydrates absorbed in the small intestine to volatile fatty acids produced by fermentation that are absorbed from the large intestines. Physiologically the best route for providing milk is by normal


suckling. Other methods utilised to provide milk include bottle or bowl feeding or feeding through a nasogastric tube. Placement of a small diameter indwelling nasogastric tube is well tolerated by foals. Small volumes of milk should be started and if tolerated, the volume gradually increased over several days. Ideally, the foal should be fed at least every 2 h. A good starting point is 5% of bodyweight for the first 24 h. If this volume is well tolerated then the volume can be increased until the foal is able or willing to nurse. In any case care must be taken to provide enough calories and protein so parenteral supplementation will be needed to make up the difference between what can be given by the enteral route and what is required. Suckling foals might prefer to eat hay instead of nurse. The addition of forage to the diet provides energy in the form of volatile fatty acids, maintains colonocyte health by the generation of butyric acid and may decrease faecal water volume (Lawrence and Lawrence 2009). In a majority of the cases preference for hay over milk is only temporary and the foal will resume nursing within 24 h. If a foal completely refuses to nurse or eat and has no additional gastrointestinal problems that would prevent the foal from nursing or eating, an indwelling nasogastric tube can be placed for supplementation. Milk can be administered in the younger foal (less than 1 month of age) and a slurry of pelleted balanced creep/foal feed to the older suckling foal. This pelleted feed would need to be ground with the addition of water, a balanced electrolyte solution or milk to form a slurry in a consistency that will go down a tube. The amount of foal feed to supplement per day is generally one pound (0.45 kg) of feed per month of age or as listed on the feed bag. This should be divided into several feeds and the foal closely monitored for complications. Possible complications include overfeeding resulting in gastric distension and colic, worsening of diarrhoea,


oesophageal irritation or aspiration pneumonia. Additional fluids i.v. or orally may need to be administered based on the foal’s hydration status and severity of diarrhoea. It is unlikely that supplementation by nasogastric tube will be needed because most foals will continue to consume some type of enteral nutrition on their own. Based on the above information, foals with diarrhoea and


no additional gastrointestinal abnormalities should be allowed to continue to nurse or eat hay with supplemental i.v. fluids if needed. Foals with severe abdominal distention, ileus, septic


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shock or colic will benefit from a brief period of feed restriction. The addition of parenteral nutrition will depend on the age of the foal and length of time it will be restricted from enteral nutrition. As soon as the foal’s gastrointestinal function stabilises enteral feeding should be reintroduced. This introduction can be intermittent allowance to nurse or, in the case of an older foal, the addition of handfuls of hay. The introduction period should be short, for instance every 2–4 h provide an enteral form of nutrition with the final goal of return to full feed/milk in 24–36 h. If the foal is receiving parenteral nutrition the rate can be decreased by half then discontinued once the foal is back to full enteral nutrition. It is important to assess the response to nutritional support.


The ideal way would be daily weight on a walk-on scale, but this is impractical because of the expense of a walk-on scale and risk of contamination of the scale with an infectious agent. Similar to adults the body scoring system established by Henneke and others (1983) can be used to give a general idea if body condition is being lost or maintained. This system is based on visual appraisal and body palpation of 6 areas including along the neck, withers, topline, tailhead, ribs and behind the shoulder (Henneke et al. 1983). The foal’s ideal body condition score is between 5 and 7. Daily monitoring of these parameters will serve as a guide to determine if the nutritional plan is appropriate. Trends in either direction, but most importantly evidence of body condition loss, can help one determine if a modification of the nutritional plan is required.


Author’s declaration of interests No conflicts of interest have been declared.


Ethical animal research Ethical review not applicable for this review article.


Source of funding


There was no private or commercial funding for this work. The author is supported by Rood and Riddle Equine Hospital.


References Alverdy, J. (1994) The effect of nutrition on gastrointestinal barrier function. Semin. Respir. Infect. 9, 248-255.


Alverdy, J., Chi, H.S. and Sheldon, G.F. (1985) The effect of parenteral nutrition on gastrointestinal immunity: the importance of enteral stimulation. Ann. Surg. 202, 681-684.


Alverdy, J., Aoys, E. and Moss, G. (1988) Total parenteral nutrition promotes bacterial translocation from the gut. Surgery 104, 185-190.


Berseth, C.L. (1992) Effect of early feeding on maturation of the premature infant’s small intestine. J. Pediatr. 120, 947-953.


Birkhahn, R.H. and Renk, C.M. (1984) Immune response and leucine oxidation in oral and intravenous fed rats. Am. J. Clin. Nutr. 39, 45-53.


Dallas, M.J., Bowling, D., Roig, J.C., Auestad, N. and Neu, J. (1998) Enteral glutamine supplementation for very-low-birth weight infants decreases hospital costs. J. Parenter. Enteral. Nutr. 22, 352-356.


Earing, J.E., Durig, A.C., Gellin, G.L., Lawrence, L.M. and Flythe, M.D. (2012) Bacterial colonization of the equine gut; comparison of mare and foal pairs by PCR-DGGE. Adv. Microbiol. 2, 79-86.


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