Hitting Pay Dirt!

Posted by Joyce Harman, DVM, MRCVS on Aug 2nd 2022

Hitting Pay Dirt!


Equine health (and human health, for that matter) is closely intertwined with soil health. Soil health directly affects plant health and the nutrients available to the plants are absorbed in turn by horses. Healthy soil and healthy horses are, therefore, inter-related. And microbial populations in the gut, called the microbiome, are also beneficiaries of this relationship.

Maintaining a healthy population of micro-organisms requires appropriate food, the correct environment and substrates (prebiotics) upon which to grow. In soil, the correct pH, minerals and organic matter all must be present. In the equine (and human) intestinal tract, the correct pH, minerals and soluble fibers (prebiotics) must all be present. Notice that the same basic ingredients are required whether the land is producing plants, or the horse/human is living. Current research is showing that the natural microbial population in the horse (and human) is primarily soil-based bacteria. So, eating a little bit of dirt is actually a good thing.


Diversity is the theme that runs through healthy living for all species. Each species needs to acquire a variety of healthy nutrients and requires a large diverse population of micro-organisms to process its food. When we feed foods with just a few, or heavily processed ingredients, as is done for our horses in bagged food; when nutrients are fed to the soil using just the three common ingredients in chemical fertilizer; and when only one variety of plant is grown in the fields as is often done with pastures, the health of all species involved declines.

Healthy soil can contain two to three tons of living organisms per acre, made up by thousands of different types of bacteria, fungi, actinomycetes, protozoa, nematodes, and algae. Earthworms are larger than the microbes, but still, are a vital part of the living soil ecosystem. There are 40,000 earthworms per healthy acre. Their job is to recycle organic matter, aerate the soil and enrich it with their castings. The jobs of the soil microbes are varied. They fix nitrogen (which helps make protein in the plant), chelate and convert minerals to an available form for plants, decompose organic matter, increase the reach of the roots towards nutrients, manufacture growth promoting substances, and exude protective substances to keep pathogens out. These are the same basic functions as the microbial population in the gut.


The goal of healthy pasture creation and management is to encourage multiple species of grasses and plants (which are also known as weeds, or actually as medicinal herbs). Learn about the native grasses in your area, and the pasture grasses that grow well locally (your local extension agent can usually help). Some native grasses do not stand up to the traffic that a pasture has, and some are not very palatable, leaving patches the horse will not eat.

Stop killing weeds but do take care that the weeds do not take over the grazing area. Mowing usually will keep the larger plants under control. In many cases mowing also keeps the vegetation at a size that is desirable for the horses to eat. If the plants become too old and fibrous, the horses will not usually eat it, missing out on its medicinal or nutritional value.

Many plants that are considered weeds are actually extremely nutritious, maybe more so than our easy keeping horses need. For example, chicory, burdock, dandelion, plantain, and curly dock all contain as much protein as alfalfa (around 20 percent). These “weeds” also contain vitamins and minerals, all beneficial to health.

Many plants are very therapeutic and are some of the top medicinal herbs in the materia medica. Dandelion is well-known for its liver and kidney benefits. It is full of minerals (potassium, calcium, and magnesium) and is a healthy diuretic, helping with edema and fluid buildup. It’s a digestive tonic, and the roots act as a blood cleanser.

Yarrow is a great tonifier and is a bitter herb for the digestive tract. Stinging nettles are most palatable very early in the year. They are high in minerals and help liver, kidney and gallbladder health. Plantain grows in most places and is great for inflammation, and the seeds are mildly laxative in the gut. Chicory is great for digestion and is nutritious. There are many more common plants normally considered weeds that are medicinal. To learn about those in your fields that you want to keep, take a plant walk with an herbalist, you will be amazed.


If you need to add diversity to what you currently have, get started by planting a small area with beneficial seeds. For the seeds to have a good chance to grow, you do need to protect them when they are first planted, perhaps with a bit of electric fence. Often it is easier to begin with planting along the fence edges, where the traffic is less, and it can be easier to protect the seedlings.

If you do not have the ability to change what is in the pasture (board your horse, rent your land, etc.), try planting a small healthy organic plot of land at home with some of these plants. Harvest a few each day and feed them to your horse, fresh with the dirt still on the roots. If the horse refuses it, it may not be the correct time for that plant to be eaten. Horses innately know the appropriate time for each plant. They also know if they need a particular plant or not.

Rotate your pastures if possible to allow the grasses and diverse plants to grow back and stay strong. Overgrazing can limit the types of plants that grow, though some of the toughest plants are valuable.


Watch what plants your horses eat, and at what time of the year. Keep a journal with notes, if you desire. Take pictures of plants you do not know and look them up online. It’s easiest to identify them when the leaves are fully grown, they have a flower, or you can see the seeds. Early growth can be harder to identify.
1. Understanding the Intestinal Microbiome in Health and Disease. Costa, Weese. Veterinary Clinics of North America: Equine Practice. Volume 34, Issue 1, April 2018, Pages 1-12. https://www.sciencedirect.com/science/article/pii/S0749073917309185?via%3Dihub
2. http://organiclifestyles.tamu.edu/soil/microbeindex.html
3. I need to change the number of earthworms per acre to 1 million, up to 12 million based on checking updated resources since mine was older. http://www.natureswayresources.com/infosheets/earthworms.html
4. Brunetti, Jerry. Health from the Hedgerow. Lecture. HMSSP. Lititz, PA 2006.