Glyphosate is a chemical herbicide found in the commercially available product Roundup and other similar products. Over the years, concerns have been raised about the safety of this chemical for people and animals, increasingly so as glyphosate-resistant versions of corn and soybeans have been developed.
Even an indoor cat could have potential exposure through diet. It is possible that exposure to spray residues from herbicides could cause chronic exposure, including through contamination of groundwater. Glyphosate does not accumulate in tissues, so your cat would only have the chemical if he is regularly getting a renewed dose. This may be happening through food ingredients that may have been sprayed at some point.
A recent study performed at Cornell University showed that 18 companion animal feeds from eight manufacturers had evidence of glyphosate in the product, and the concentrations detected appeared to correlate with crude fiber content. This suggests that the source of this chemical may be plant material used in the production of these foods. Cat food generally contains less plant material than dog food, since cats are obligate carnivores, but plant material is used in the production of most cat foods.
Another study published by the NY State Department of Health detected glyphosate in the urine of all 30 cats included in the study. The 30 canine subjects in this study had lower amounts of glyphosate detected than that seen in the cats.
While the feline exposure to glysphosate suggested in both of these studies was lower than the established human safe exposure level, chronic exposure studies have not been done. Work from Europe suggests at least some potential for glyphosate toxicity to cats, with vomiting, loss of appetite, and lethargy the most common signs seen. Fatal respiratory effects were seen in a small number of cats exposed to glyphosate. A current thought is that it may not be the glyphosate itself that is toxic to cats, but rather one or more of the “inert ingredients” in these herbicide products.
The EPA’s draft ecological risk assessment for glyphosate found: potential risks to plants (aquatic and terrestrial); potential risks to birds from acute or short-term exposure and to mammals from chronic or long-term exposure; glyphosate is not expected to adversely impact aquatic animals but does have an effect on aquatic plants; and glyphosate is of low toxicity to honeybees.
The Health Research Institute laboratory, a non-profit research group, is currently taking samples to evaluate levels of glyphosate in the urine of companion animals and to determine if there are adverse health effects from exposure to this chemical. A small fee is charged for sample submission. If you would like to participate, you can learn more at https://hrilabs.org/animalstudy/.