Probiotics can be an important part of natural horse nutrition. Probiotics can help horses that have weight problems, intestinal problems, or are on or have been on antibiotics. Probiotics can contribute to a heathy intestinal microflora, which is often challenged during foaling, weaning, showing, hauling, antibiotic treatment or vaccinating and deworming.
Some horse probiotics are:
More information on probiotics: AllAbout Probiotics