Question
I have seen different products advertised that are supposed to help with sand colic. As I understand it, they are so-called “sand coagulants.” Do these products really work and do they have any adverse effects on a horse’s digestive system?
Answer
It has been reported that sand buildup in the digestive tract of horses may be responsible for as high as 30% of colic cases, especially in sandy soil areas. Several different treatment schemes have been used to move sand through the digestive system. Recently, several research reports have been published that investigate movement of sand through the equine digestive system. A University of Florida study investigated inadvertent sand intake during feeding in which a sweet feed or a grass hay was fed on or above a known amount of sand. This study concluded that feeding programs which place the horse’s grain in potential contact with sand increase the intake of sand. In other words, horses that drop and attempt to retrieve grain from sandy soils accumulate sand in the gut.
Essentially no sand was consumed when grass hay was fed on sand. Researchers at the University of Florida also reported that horses fed small amounts of forage (0.75% of body weight) spent more time eating manure and thus probably consumed more sand. Treatments for removal of sand from the digestive tract are being tested. Researchers have put known volumes of sand into the horse’s digestive system and then measured the ability of different treatment protocols to remove the sand. A study conducted at the University of Illinois reported that ponies dosed with psyllium in an attempt to remove sand were not any more efficient at sand removal than ponies given a control diet.
They concluded that psyllium had no apparent effect on sand removal from the horse’s large intestine. The University of Florida tested four means of sand removal: 1) hay fed at 1.5% of body weight, 2) hay fed at 2.5% of body weight, 3) hay fed at 1.5% of body weight plus psyllium fed in a single daily dose and 4) hay fed at 1.5% of body weight with psyllium fed twice daily. The results indicated that feeding large amounts of hay (2.5% of body weight, 25 lbs. for a 1000 lb. horse) uniformly produced the largest sand output. Other experiments studied feeding wheat bran and dosing with mineral oil as methods to remove sand. Both protocols proved ineffective for sand removal.
In summary, there does not appear to be any advantage to feeding or treating with psyllium, bran or mineral oil over a basic hay diet for removal of sand from the digestive system of horses. Are different sand clearance supplements miracles for the removal of sand? The answer seems to be no. Hay appears to be primarily responsible for movement of sand through the gut and the higher the hay intake, the faster the sand is moved through the digestive system. Do these supplements have adverse effects on the digestive system? To date, they have not been shown to have negative effects on the digestive system.
