Protecting the Equine Gut from Herbicide and Pesticide Exposure
Recently a customer notified me that she had her feed tested for glyphosate (Roundup) residue. She had been happy with the feed until she noticed her horses weren’t thriving on it as they had been; they were losing weight and muscle. She decided to have the feed tested, and it came back positive.
Exposure to pesticides and herbicides: Environmental toxins
The wide use of pesticides and herbicides exposes horses, dogs, cats, and humans to these environmental toxins. The current research is pretty clear about how environmental toxins affect the gut.
It’s not just feed. According to a 2020 NC State Extension publication, there are specific herbicides of concern — aminopyralid, clopyralid and picloram, registered for application to pasture, grain crops, lawns, turf, certain vegetables and fruits — that remain active in treated soil, in hay and pasture, and throughout the digestive tracts of animals, even retaining their herbicidal activity long after being excreted in urine and manure.
Some field reports indicate that complete deactivation and breakdown of these herbicides can take several years. According to NC State Extension, hay has been reported to have residual herbicide activity after three years of storage in dry, dark barns.1
According to a 2021 report from North Dakota State University there are concerns about herbicide carryover in soils. Soils with a pH of <6.0 can allow certain herbicides to persist. Soils with less than 2% organic matter are at risk for herbicide carryover because they have less microbial activity.
Another huge factor is rainfall. There is a higher risk of herbicide carryover when there is below-average rainfall in a growing season.2
How herbicide carryover can affect homes and farms
According to NC State Extension, degradation of herbicides is slow in manure and compost. When mulches, manures, or composts with residual herbicide activity are applied to fields and gardens, “potentially devastating damage can occur.”3
It is recommended to talk to your hay supplier, mulch supplier, and compost sources to find out what herbicides have been used. If horse owners and farm owners don’t know the herbicide levels in their hay, it’s recommended they do not sell or give away manure for home or commercial gardens.
Current data on herbicides and pesticides
More than one billion pounds of herbicides and pesticides are applied annually on farms, backyards and urban areas in the US. These chemical compounds are contributing to biodiversity loss in soils, aquatic ecosystems, and the loss of invertebrates such as mayflies and dragonflies.4, 5
Glyphosate (Roundup) is the most widely used herbicide in the world. It can be found in a majority of rivers, streams and wastewater treatment plants, and 70% of rainfall samples.6
A 2022 study on stallion spermatozoa (sperm cells), published in the journal Theriogenology, showed that Roundup is more toxic than its active molecule glyphosate alone. Roundup was found to significantly decrease total and progressive motility, viability, acrosome integrity, mitochondrial activity, and the percentage of live stallion spermatozoa.7
A 2021 study published in Nature demonstrated that glyphosate-based herbicides can disrupt host microbiota and affect host health. The researchers found a link that glyphosate plays in the dysregulation of homocysteine, linked to inflammation.8
The tight junctions of the gut
Tight junctions are the gatekeepers that regulate micronutrients and are the frontline of defense. Tight junction dysfunction has been linked to environmental toxins; glyphosate has been linked to injury of the tight junctions of the gut, as well as signaling pathways within the body, endocrine functions, and inflammation. According to Carol Shwetz, DVM, Alberta, Canada:
“Given the complexity with which glyphosate is proposed to adversely affect mammalian biology and its increasing prevalence in the food chain and environment of horses, it is plausible that glyphosate exposure may be a contributing factor to illnesses in horses.
The list of clinical suspects include those illnesses associated with gut dysbiosis i.e. gastric and/or hindgut ulceration, equine metabolic diseases i.e. insulin resistance, equine metabolic syndrome, Cushings, chronic inflammation and weaknesses of the musculoskeletal systems, laminitis, weak hoof structure, and liver and kidney disease.”9
The seat of health resides in the gut
Studies have shown that glyphosate exposure alters gut microbial composition, causing dysbiosis — an imbalance in gut microflora homeostasis. Opportunistic pathogens like E.coli and Staphylococcus have developed mutations that allow them to be unharmed by glyphosate, contributing to the imbalance.
Maintaining a healthy ecosystem in the gut is one of the best ways to help your horse’s body deal with environmental toxins. One of the best ways to help the gut microbiome is to ensure the diversity of beneficial organisms and provide the food they need to colonize and thrive. In addition, fulvic and humic acids in the diet help close the tight junctions of the gut.
Hedgerow GI: Maintaining GI tract homeostasis
BioStar’s Hedgerow GI is an environmental support formula for horses. Hedgerow GI provides:
- a variety of active, beneficial microorganisms in concentrations that can colonize the GI tract, with 150 million CFUs per serving.
- the spore bacteria Bacillus subtilis, which helps form a barrier to keep opportunistic pathogens from proliferating.
- prebiotics and postbiotics to feed the colonies and provide important metabolites like short-chain fatty acids.
- fulvic and humic acids from reed sedge peat to reduce dysfunction of tight junctions in the gut.
- patented fermented turmeric to support the microbiome, support regulation of inflammation, and support the immune system.
- specific traditional herbs for gut health and for diversity of the gut ecosystem.
Environmental stressors are a real challenge for all of us, including our horses. Maintaining a healthy gut microbiome and gut ecosystem is essential. BioStar’s Hedgerow GI provides your horse with the benefits of science and nature.
For more on Hedgerow GI, read our in-depth article