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Gut Balancer - Impact on Fecal Scores

QUESTION: Is a live yeast probiotic and MOS/betaglucan prebiotic beneficial to horses with hindgut dysfunction?


  • Dysfunction and disease of the gastrointestinal (GI) tract is common in horses with colic being the most severe1-3. Identified risk factors for colic include change in stabling conditions, recent change in diet and level of activity, decreased exposure to pasture, lack of access to water and transport3,4.
  • Low-grade hindgut disturbance and change in hindgut microbial populations can be caused by high starch diets and abrupt dietary change4-6. Such shifts in microbial populations can decrease the efficiency of food digestion5 and the metabolism and absorption of vitamins and minerals.
  • Yeast has been proposed to support GI microbial populations in a number of species, reducing the risk of GI problems, acidosis and increasing digestibility7. Similarly, yeasts may be able to beneficially modify large intestine function in the horse5,6,8,9.

Aim of Study

To develop a nutritional supplement (Gut Balancer, Science Supplements) supporting hindgut function in the horse. Primary requirements in development of the supplement were effectiveness and safety.

Study Design

  • Prospective clinical case series = a group of horses selected for a particular reason (loose droppings in this study) was followed over several weeks.

Study Outline

Twenty-nine horses with chronic (over 4 weeks) loose droppings were recruited. Loose droppings were chosen as an indirect measure of large intestinal function/dysfunction as they require no owner intervention and are readily observable. It was hypothesized that improvement in large intestinal function would be reflected by better consistency droppings. Owners recorded fecal consistency each day using a simple 5-point scale for scoring the consistency of the droppings (0 liquid; 1 semi-liquid; 2 soft; 3 normal; 4 hard). Each score was accompanied by a photo to try to improve consistency in scoring over time and between different owners taking part in the trials. Owners were instructed to feed 40g of live yeast probiotic and MOS/betaglucan prebiotic (Gut Balancer) per day, split between two feeds. If no change in fecal score was observed in 7 days, 80g of Gut Balancer (2 x 40g) was administered daily for a further 7 days.

Study Results

  • Improved fecal consistency within 7 days was reported for 24/29 (83%) horses with loose droppings. Fecal scores were significantly improved after 2 days of feeding Gut Balancer (Figure 1).
  • Normal fecal consistency was achieved in 15/29 (52%) horses. Five horses (17%) did not respond with a change in dropping score in the first 7 days. These horses were fed 80g supplement daily for a further 7 days resulting in 4/5 (80%) producing normal droppings.
Graph of change in fecal scores over 7 days

Figure 1. The effect of feeding Gut Balancer (40g per day) on median owner-recorded fecal score in 29 horses with loose droppings. Fecal score: 0 liquid; 1 semi-liquid; 2 soft; 3 normal; 4 hard. * shows significant difference in median fecal score from pre-trial (P<0.03).


  1. Ireland et al., Factors associated with mortality of geriatric horses in the United Kingdom. Preventive Vet. Med. 2011. 101(3):204-218.
  2. Tinker et al., Prospective study of equine colic incidence and mortality. Equine Vet J. 1997. 29(6): 448-453.
  3. Cohen Epidemiology of Colic. Veterinary Clinics of North America: Equine Practice, 1997.13(2):191-201.
  4. Hudson et al. Feeding practices associated with colic in horses J Am Vet Med Assoc 2001. 219:1419–1425
  5. Salem et al. Influence of Feeding Horses a High Fibre Diet With or Without Live Yeast Cultures Supplementation on Feed Intake, Nutrient Digestion, Blood Chemistry, Faecal Coliform Count, and In Vitro Faecal Fermentation. J Equine Vet Sci. 2016. 39:12-19.
  6. Grimm et al. Effect of yeast supplementation on hindgut microbiota and digestibility of horses subjected to an abrupt change of hays. Livestock Sci. 2016.186:34-40.
  7. Chaucheyras-Durand and Durand Probiotics in animal nutrition and health. Beneficial Microbes 2010 1:1, 3-9
  8. Proudman et al. Racehorse faecal metabolome and microbiome. Equine Vet J. 2015. 47: 580-586.
  9. Jouany et al. Effect of live yeast culture supplementation on apparent digestibility and rate of passage in horses fed a high-fibre or high-starch diet. J Animal Sci. 2008. 86(2):339–347.
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