A type of obstructive colic caused by the ingestion of sometimes very large amounts of sand and soil. This most commonly coincides with the first flush of grass growth following autumn rains after summer drought conditions. As the lush new grass sprouts from bare sandy soils the horse pulls it up, roots and all, with adherent sand and consumes the whole lot. Feeding hay directly from sandy ground may also result in a slow build-up of ingested sand.
Within a day or two under the right conditions, sand accumulates, especially in the caecum and large colon, causing irritation to the bowel wall and some degree of obstruction. Normal motility is hampered by the sheer weight of wet sand and pockets of gas may form and become trapped. Distension of the bowel ensues with colic pain, generally low grade initially but potentially becoming acute and severe depending on the degree of sand obstruction. Sandy faeces may be passed, or sandy diarrhoea. Manure can be collected in a jar of water, shaken, and examined visually for the presence of sand settling out. Symptoms are highly variable according to the degree of obstruction and its duration.
Treatment requires removing the horse from the sandy ground and pain relief often combined with a large dose of mineral oil or other laxative to help lubricate the obstruction and move it along the gut. In a small percentage of cases medical treatment is insufficient and abdominal surgery is required to explore the site of obstruction and relieve it. It is not uncommon from 60-100kg of wet sand to be removed from the gut in surgical cases.
Mild cases can often be treated by keeping the horse off the sand and feeding ad lib hay. Psyllium husk is sometimes fed in an attempt to help remove the sand from the gut by lubrication and increased water retention. However, veterinary attention should be sought for any horse showing signs of colic pain.