Equine Health

Improve Digestive Health and Get the Most From Your Feeding Program

Tara Hembrooke, Ph.D., M.S., and Sina Wallace, Ph.D., University of California, Davis

A balance must be maintained between the microflora that normally reside in the horse’s intestinal tract and pathogenic microbes that release toxins and cause clinical disease. The pathogenic organisms that are of concern in horses include Salmonella spp., Clostridium difficile, and Clostridium perfringens, which have been associated with diarrhea and colitis in adult horses and diarrhea and septicemia in foals.

Pathogenic Bacteria

Diarrhea in adult horses and foals is a significant source of morbidity and mortality. The results of a retrospective study conducted in the late 1990’s indicated that more than 25% of horses admitted to a teaching hospital with acute diarrhea did not survive. Of these horses, those treated with antimicrobial drugs, a contributing factor to bacterial overgrowth, had the highest risk of not surviving. Currently, Salmonella spp. are the most frequently cultured pathogenic bacteria in adult horses with diarrhea. Salmonella organisms also have been implicated in post-surgical diarrhea and neonatal septicemia, which is significant because septicemia remains one of the leading causes of illness and death in young foals. In addition, Salmonella spp. are increasingly problematic in the hospital setting with fatality rates as high as 38%. Clostridium difficile has also been isolated from and associated with diarrhea in adult horses. Foal heat diarrhea, which develops in foals 9 to 14 days old, is considered to be a manifestation of normal changes in the microbial ecology of the intestinal tract. However, neonatal diarrhea develops at an earlier age and is often due to gram-negative bacteria, including Salmonella, and gram positive Clostridium species.

A complex and dangerous condition

Colitis is a life threatening condition in adult horses and foals, with reported mortality rates of 22% for horses and 18% for foals. The results of one study indicated that adult horses with colitis that test positive for Clostridium difficile are less likely to survive than horses with colitis lacking detectable levels of Clostridium difficile. Additionally, one university teaching hospital reported a mortality rate of 54% for foals with Clostridium perfringens-associated colitis over a 10-year period. During one particular year, the mortality rate of foals with Clostridium perfringens type C was 83%.

Smectite, a naturally occurring organomineral, has shown promise as a protectant against the overgrowth of pathogenic bacteria by reducing the harmful effects of bacterial toxins. Bio-Sponge™, the commercially available Di-Tri-Octahedral smectite product from Platinum Performance Inc., bound 99% of Clostridium difficile toxins A and B and Clostridium perfringens enterotoxins in one in vitro study and effectively neutralized Clostridium perfringens alpha, beta, and beta-2 toxins in another study. Bio-Sponge™ is suggested to work because it has an ionic charge that allows it to bind to various toxins, creates an environment that is not favorable to the growth of clostridial bacteria, or directly prevents the absorption of toxins by coating the intestinal wall. Due to its ability to bind and neutralize clostridial toxins, Bio-Sponge™ may be particularly useful in horses with colitis and diarrhea caused by clostridial organisms.

Promising results using Bio-Sponge™

Recent studies in adult horses indicate that Bio-Sponge™ may be beneficial in horses after colic surgery and in adult horses with antibiotic-induced colitis. For example, researchers at the University of California, Davis reported a significant decrease in the incidence of diarrhea after colic surgery in horses administered Bio-Sponge™ when compared with horses receiving a placebo (Figure 1). Whereas only 10% of horses administered Bio-Sponge™ developed diarrhea, 43% of the placebo-treated horses developed diarrhea. In addition, total WBC and neutrophil counts remained significantly higher 24 and 72 hours after surgery in the horses administered Bio-Sponge™ when compared to the placebo-treated horses (Figure 2). Bio-Sponge™ may also be beneficial in the management of horses with colitis, as the results of a recent pilot study indicated that Bio-Sponge™ helped maintain normal gastrointestinal function in horses with antibiotic-induced colitis.

Conclusion

Bio-Sponge™, an intestinal protectant composed of DTO smectite, may help create an intestinal environment that protects against the harmful effects of microbial overgrowth and toxin production. Additionally, Bio-Sponge™ may be beneficial in horses with endotoxemia, post-operative diarrhea, and after toxin ingestion.

Putting it into Practice

• To reduce the risk of diet-induced colitis, make all dietary changes slowly, over 10-14 days.
• Include Bio-Sponge™ supplementation in the veterinary care of adult horses with acute colitis.
• Supplement foals and adult horses affected with diarrhea with Bio-Sponge™ to support gastrointestinal health.
• After an adequate volume of high quality colostrum has been ingested, supplement with Bio-Sponge™ to support the gastrointestinal health of foals on farms with a history of endemic Rotavirus or Clostridium difficile.