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EQUINE VETERINARY EDUCATION / AE / MARCH 2016


Feeding horses following impaction is best initiated without grain or pasture until normal intestinal transit is established (White and Dabareiner 1997). When a colonic impaction is identified, initial therapy typically consists of a combination of analgesics, sedative analgesics, oral and/or intravenous fluids, and laxatives. Decreased faecal output and appetite are commonly reported (Hallowell 2008). As such, nutritional management involves feed restriction until repeat examination per rectum or manure output suggests that refeeding will not add to the impaction (White and Dabareiner 1997). As resolution of the impaction becomes evident, forage meals are slowly reintroduced. The authors typically reintroduce hay in small feedings 4–6 times per day, beginning with several handfuls to one-quarter flake, and increasing over 2–4 days until returned to maintenance feeding levels. Weighing hay is recommend to determine the ideal maintenance rate, as a single flake may weigh 1–2 kg depending on forage type. In the immediate post colic period, the authors advocate eliminating concentrates for a short period of 3–7 days, depending on colic severity, following gradual reintroduction. For routine feeding of concentrate, provision of more frequent (3 times/day), smaller meals (each <0.4% of bodyweight) throughout the day is recommended to minimise delivery of undigested hydrolysable carbohydrate to the hindgut (Geor and Harris 2007). Ultimately, a well established target for healthy adult horses is consumption of approximately 2– 2.5% of their body weight daily, with at least 1.5% of body weight as good quality hay or pasture (Geor and Harris 2007; NRC 2007).


Nutritional management of sand enteropathy


Sand colic can often be resolved with medical treatment, but nutritional management for cases that require surgery should follow post operative colic recommendations (Geor 2008). Acute medical management of sand enteropathy typically involves a combination of mineral oil and psyllium supplementation, occasionally with the addition of magnesium sulfate. In one retrospective study evaluating medical management of sand enteropathy, 90% of horses survived to discharge and 50% of horses that had repeat abdominal radiographs demonstrated an improvement in degree of sand accumulation (Hart et al. 2013). The most common laxative protocol in the study by Hart et al. (2013) was a combination of psyllium and mineral oil administered via nasogastric tube. Recommendations for nutritional management of sand colic have varied from highly digestible forage or pelleted feed for 2–3 weeks after sand has cleared, to provision of free choice hay, to no dietary change at all (Stratton-Phelps and Fascetti 2003). The most important treatment for horses with sand colic is to change their feeding management to prevent further ingestion of sand (Stratton-Phelps and Fascetti 2003). Routine recommendations for horses on pasture include feeding horses in bins, racks or structures elevated above the ground to reduce inadvertent consumption of sand. If horses are fed on the ground, provision of ground covering such as rubber mats or a concrete slab, should be provided to minimise exposure to sand. Feeding directly on the ground in paddocks where there is short or no grass is a published risk factor for sand-related gastrointestinal disease (Husted et al.


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2005). Published studies regarding the efficacy of various supplements for prevention and removal of sand are limited. A study conducted at the University of Illinois found that psyllium treatment (1 g/kg bwt for 11 days) was no more effective than nonsupplementation for removing sand (10 g/ kg bwt) placed surgically into the caecum of ponies (Hammock et al. 1998). Further, the researchers reported that simply housing ponies away from sand resulted in clearance of 70% of the sand load over 11 days. The University of Florida administered a small amount of sand (300 g) via nasogastric tube and tested 4 means of sand removal: 1) hay fed at 1.5% of bodyweight; 2) hay fed at 2.5% of bodyweight; 3) hay fed at 1.5% of bodyweight plus psyllium (0.5 g/kg bwt) fed in a single dose; and 4) hay fed at 1.5% of bodyweight with psyllium (0.25 g/kg bwt) fed twice daily for 6 days. The results indicated that feeding large amounts of hay (2.5% of bodyweight, 11 kg for a 450 kg horse) uniformly produced the largest sand output (Lieb and Weise 1999). A study in Austria fed horses 1 kg sand mixed with the daily ration of grain for 5 days, followed by treatment with mineral oil (2 l q.i.d.) or mineral oil plus psyllium (1 g/kg bwt) and found greater excretion of faecal ash (as a measure of sand clearance) with the combination compared to mineral oil alone (Hotwagner and Iben 2008). A study in Colorado reported that a supplement containing psyllium, probiotics and prebiotics resulted in an increase in faecal sand output in horses with naturally occurring sand load (Landes et al. 2008). However, both the Austrian and Colorado studies failed to include an untreated control, making it difficult to discern whether psyllium, or simply a change of management (and possible sand exposure) was more effective.


Nutritional management of recurrent colic from inflammatory bowel disease


Inflammatory bowel diseases (IBD) are characterised by infiltration of the intestinal mucosa and submucosa with populations of plasma cells, eosinophils, lymphocytes, basophils or macrophages. Histological classification of the different IBD subtyptes includes lymphocytic-plasmacytic enterocolitis, granulomatous enteritis, multisystemic eosinophilic epitheliotropic disease, diffuse eosinophilic enteritis, and idiopathic focal eosinophilic enteritis (Edwards et al. 2000; Schumacher et al. 2000; Archer et al. 2006; Perez Olmos et al. 2006). Clinical signs of IBD in the horse include weight loss, colic, lethargy and dependent oedema, often associated with enteric protein loss and malabsorption of nutrients, including glucose. Medical management of these cases routinely involves corticosteroid treatment and some dietary management. Historically, prognosis for equine IBD has been considered to be guarded to poor (Kemper et al. 2000; Schumacher et al. 2000; McCue et al. 2003). However, a more recent study looked at response to treatment of presumptive IBD with corticosteroids and anthelmintics and reported an overall prognosis for long-term survival to be fair to moderate, with a 3-year survival rate of 65% (Kaikkonen et al. 2014). That same study identified a low peak xylose concentration in absorption testing to be associated with a less favourable prognosis (Kaikkonen et al. 2014). Discussion of dietary management in published IBD studies is limited, probably because nutritional management of these cases


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