Probiotics make better poo shock! Many horse owners thought they knew this already. Owners generally give them to enhance digestive function; they belong to a group of immunomodulators which can boost the immune system, and some existing research suggests beneficial effects, although in one study of foals the probiotic appeared to make diarrhoea worse. Exactly how they work still isn’t clear, and which organisms are best for equine use hasn’t been established. In this study researchers studied a variety of probiotics and found some benefits including reduced diarrhoea, enhanced white blood cell function and better faecal consistency; however overall efficacy remains unclear. Future research will target their role in parasite control, but it’s too soon to ditch those wormers. Bonus points if you can suggest environmental enhancements for the horse in the picture!