Effect of Glyphosate on Dogs

Glyphosate is the generic name for a family of broad-spectrum herbicides that includes products marketed under such names as Roundup, Accord or Rodeo. Glyphosate is commonly used as a non-selective plant killer for the control of grasses, broad leaf and woody plants. According to the website maintained by the Extension Offices of Cornell University, the principal manufacturer of glyphosate is Monsanto. It is chemically known as N-(phosphonomethyl)glycine.

  1. Acute Effects

    • The Environmental Protection Agency categorizes glyphosate as low in toxicity. No lethal doses for dogs have been established. But, according to the EPA report, "Reregistration Eligibility Decision Document: Glyphosate," published in 1993, testing on rats seem to indicate that an ingested dose of about 4.5 percent of the animal's body weight is fatal to half the animals. Dog owners should make every precaution to prevent the animal from ingesting glyphosate; however, accidental exposure to small doses should not overly alarm pet owners.

    Chronic Effects

    • Cornell University reported the EPA findings listed in the document, "Pesticide Tolerance for Glyphosate," published in the Federal Register in 1992. This document detailed tests exposing dogs to glyphosate at a rate of 500 milligrams per kilogram of body weight per day for 21 days. This amounts to a daily dosage equal to 0.5 percent of the animal's body weight each day. The testing produced no observable effects on the dogs. The same testing produced no reproductive changes in test animals.

    Skin and Eye Effects

    • Tests for skin and eye reactions have not been performed on dogs but were done on rabbits. The World Health Organization noted skin swelling, in a study titled "Glyphosate," published in Switzerland in 1994. The study used a dose of 5,000 milligrams per kilogram, or 5 percent of the rabbit's body weight.

    Cancer

    • Dogs that were given doses of up to 500 milligrams per kilogram per day did not see an increase in incidents of cancer, according to the EPA. The EPA performed the tests on beagles over a one-year period. The tests did indicate some weight loss and damage to the pancreas. The EPA conducted the testing in 1990 and published the report through the Integrated Risk Information System.

    Glyphosate and Mammals

    • Most glyphosate consumed by dogs and other mammals will pass from the body with other waste, because it's poorly absorbed by the digestive tract. According to the EPA document, "Reregistration Eligibility Decision Document: Glyphosate," it does not accumulate in animal tissue in significant amounts. The report indicates that about 98 percent of the chemical passes from the body in the urine or feces over the course of seven days.