A Modern Look at Probiotics

The hottest topic in research these days is the microbiome. This term describes the microbial population of good bugs in the gut that do most of the work of the digestion. With new DNA measuring procedures, it is possible to sort out in detail the different types of organisms that live in the gut. In the past, all we could do was culture the manure, and all we got was lots of bugs making a mess. The research is constantly evolving, and every year our knowledge grows. Along with that knowledge is coming a revolution in how we approach probiotic supplementation.

Species most commonly present in the gut are not the ones commonly seen in supplements. This is partly because many microbes are not shelf-stable and cannot be incorporated into feedable supplements at this time. It is also because the knowledge of exactly what we need to supplement is just beginning. The old probiotics have been a significant help to the gut, mostly by creating a positive environment for the species that naturally live there.

Grain vs Grass

Research has clearly shown differences in microbe populations when grain-fed horses were compared to grass-fed. In several studies, grass-fed horses had higher levels of the Firmicutes, Fibrobacter spp (fiber digesting) and Ruminococcaceae phyla of bacteria. Grain fed horses had higher proportions of Clostridiaceae (Lachnospiraceae-carbohydtate digesting bacteria) and Bacteroidetes with decreased fiber digesting bacteria (Fibrobacter spp. and Ruminococcaceae). Other studies showed 10 times higher levels of lactobacillus spp in grain fed horses compared to grass fed horses. The take away from these articles are that we need to feed a more forage based diet to keep the gut healthy, prevent colic and maximize performance.


In one study, there were noticeable changes in all types of microbiota after transport, fasting and anesthesia. What this tells us is that stress does affect the microbiome. Another study showed that there were significant changes in mare’s microbiota just before or during a post-partum colic.

Microbiome and health 

If you think a healthy microbial population just affect gut health and disease, think again. Yes, stool problems, colic, poor appetite, weight issues are all related to the gut directly. But the gut directly affects the immune system: microbiota have direct and indirect actions on the 70% of the immune system that lines the gut. Microbes affect the brain, they do the actual work of digesting and manufacture a large variety of nutrients from vitamins to antioxidants. More articles to come about the microbiota and what it does.

How to cultivate a healthy microbiome

Simple, basic but high quality standard probiotics like I have been using for years in my practice certainly help support the microbes in the gut. But the bugs we really need, that live in the gut, are similar or the same as the microbes that live in the soil. There are new ways to help those native bugs. One is through a new product called Restore, which is a mineral product that basically feeds the microbiome that is there, replaces the natural metabolites that the bacteria produce so that the gut wall can heal. ProBi also encourages a healthy environment for the bacteria, rather than being a true probiotic.

An exciting new idea that came to me as I have been researching the microbiome, is to create and cultivate a corner of the garden/paddock/yard as you would a wonderful organic garden. The goal of a healthy plot of soil for growing food is to add organic matter and create soil full of micro-organisms. Soil actually contains from several hundred to thousands of pounds microorganisms per acre! Then plant a variety of plants that horses would like to eat and allow 10 minutes of grazing per day. I am working on some planting ideas (future newsletters). Dogs are omnivores and can graze there also if they are interested in eating plant material (and many are)

The microbiome is really the key to health. Keep working to enhance it and your animal’s health will be better.

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