Glyphosate's Impact on Animal Health?

The USDA's recent decision to approve Roundup Ready® alfalfa has rekindled the controversy over the use of genetically modified organisms in the food chain. A letter addressed to Agriculture Secretary Tom Vilsak has been cited or reproduced on numerous web pages and blogs and has heightened the controversy. (such as at accessed 3/8/11) The letter announces the discovery of a new pathogenic life form supposedly associated with Roundup Ready® corn or soybeans, or possibly glyphosate itself, and warns of potentially devastating consequences of this new pathogen on plant and animal health.

The letter describes this new life form as being previously unknown, a "micro-fungal-like organism" having the size of a medium-sized virus, and present in "high concentrations" in Roundup Ready® soybean meal and corn, distillers' meal, pig stomach contents, and pig and cattle placentas. Furthermore, the letter indicates that this organism has been found in a variety of livestock that have had spontaneous abortions and infertility and that preliminary experiments have shown that it can cause abortions in a clinical setting. The letter also alludes to a supposed escalation in the frequency of abortions and infertility in US livestock over the past few years, and speculates that this new pathogen may be responsible.

As near as we can determine, this new organism has not yet been described in scientific publications or in oral presentations at scientific meetings. Results from research demonstrating its ability to cause abortions or other negative health consequences in animals have not been presented in these settings either. It is very unusual that preliminary experiments that demonstrate an ability of an organism to cause abortion could already be competed without some description of the organism itself being presented to scientists in written or oral communications. The discovery of a new organism, especially a pathogen, is usually revealed to the scientific community first for review of the findings by one's peers and to encourage further research on the organism and any potential consequences of the findings on human, animal, or plant health. If such a new organism, especially one with the potential detrimental effects on livestock health as described in some of these internet postings, has been discovered, the relevant information should be immediately available for review by scientists and veterinary diagnosticians and practitioners.

These postings also refer to the "escalating frequency" of abortions and infertility in livestock in the US. It is true that abortion and infertility are important causes of decreased animal health and economic loss, and indeed, there are many potential causes of livestock abortion and infertility. However, we are unaware of any documented "escalation" in their frequency over the last several decades during which time glyphosate or Roundup Ready® varieties of crops have been available and used widely.

Until such time as the claims of a new pathogen and increased levels of animal disease associated with it or glyphosate use, such as described in these recent internet postings, have been subjected to scientific review, farmers and livestock owners should be very cautious about attaching credibility to them. Good record keeping, preventive health measures, and timely diagnostic procedures and laboratory submissions are the foundation of maintaining animal health.

EDITOR's NOTE: You will find 3 related articles regarding recent concerns surrounding the use of glyphosate in this week's OSU Extension Agronomic Crops Team C.O.R.N. newsletter. The articles and links include Glyphosate Effects on the Occurance and Development of Soybean Diseases, Trying to Sift Through the Current Wealth of Information (and Misinformation) About Glyphosate, and Glyphosate Application Effects on Soybean Manganese Nutrition.