Direct-fed Microbial Products and Laminitis  

"Maintaining a consistent digestive tract can reduce the incidence of laminitis."

Laminitis and the resulting hoof damage originates with changes in a horse’s blood chemistry.

Excessive fermentation of grain, and sometimes lush forages, in the digestive tract initiates a

sequence of events leading to grain or grass founder. Direct-fed microbial cultures feature beneficial

bacteria and yeast or yeast culture. Experience has led many in the horse industry to conclude that

direct-fed microbial products, or probiotics, can be an effective management aid for reducing the

opportunities for laminitis and enhancing hoof recovery.

Grain digestion results in lower pH levels in a horse’s intestinal tract than forage fermentation, as well

as shifts in the type of bacteria present.

 Over consumption of grain or rapid starch fermentation creates conditions favorable to undesirable bacteria that can dramatically alter the digestive tract environment.

The harmful bacteria secrete a lactate structurally constructed to resist metabolism by

horses. Consequently, the lactate concentration increases in the intestinal tract and blood system

while depressing pH levels. While horses have many means of stabilizing their blood pH, severe

increases in intestinal and blood lactate will impair normal body function. In addition, acidity in the

horse’s digestive system results in situations leading to the production and absorption of bacterial


The endotoxins and other microbial or horse metabolic products can restrict blood flow from the hoof.

Reduced blood circulation prevents oxygen from reaching hoof cells for normal functioning. Hoof

damage increases with the amount of time that hoof cells are deprived of oxygen.

Maintaining a consistent digestive tract can reduce the incidence of laminitis.

 Avoiding large feedings of concentrates and providing a greater proportion of quality forages are a few of many management practices that aid in establishing a steady intestinal tract. Horse owners are increasingly using certain naturally occurring bacterial and yeast cultures as management tools to stabilize the digestive tract.

In addition to potentially shifting the horse’s diet to a safer percentage of concentrates, research

suggests that the microbial cultures aid in controlling the harmful pH-reducing bacteria. Horses are

able to metabolize the form of lactate produced by the beneficial bacterial species approved by the

Food and Drug Administration. Scientists are evaluating various methods the bacteria use to limit the

growth of the damaging bacteria. Research also indicates that feeding yeast and yeast culture aids in

creating a positive balance of health-promoting bacteria.

Research indicates that these direct-fed microbial products enhance fiber fermentation to enable

horses to receive a greater proportion of their energy from forages. Although some horse owners are

able to feed greater proportions of forages while supplementing their horses with microbial cultures,

each horse must be evaluated individually and fed for the desired body condition.

Direct-fed microbial cultures attach to the lining of the small intestine to improve nutrient absorption,

according to numerous scientific studies. Enhancing nutrient absorption could improve hoof wall

rehabilitation after foundering. Many Farriers indicate that improved hoof growth and integrity are

telltale signs of a horse supplemented with microbial cultures.

Laminitis results from alterations in the horse’s blood chemistry.

While direct-fed microbials will not prevent laminitis, the horse industry is learning that these cultures can be a valuable management aid for reducing the opportunities of digestive-related laminitis while also enhancing the possibility of repairing the integrity of the hoof wall after foundering.

Larry Roth, Ph.D., PAS is a research scientist with the Conklin Co. Inc.