What would you recommend for an older horse with continual loose, dark bowels and no other symptoms?

Continual loose, dark bowels are indeed a concern. There can be many things to consider in regards to causes, such as worms, ulcers, malabsorption issues, infection, inflammation, nutrition and even cancer. Figuring out the cause is the best way to fix the problem and this is best done in partnership with your vet, who can run diagnostic testing on your horse.

 - Health4Horses vet team