Thoughts on GM Grass Killing Texas Cattle

CBS News ran a story titled “GM grass linked to Texas cattle deaths” earlier today. In a nutshell, the story reports that 15 cows died from cyanide poisoning after eating genetically modified grass. See for more.

There’s a pretty clear culprit, from the reporting thus far: cows die from cyanide poisoning, grass tests positive for cyanide, so the grass did it. If I were on the jury, I’d definitely vote guilty. But why start the headline with “GM grass”?

Questions I Have:

How often do plants produce compounds that can lead to cyanide poisoning? The story sounds horrific: Fields of cyanide gas… animals passing out… queue WWII flick… (Or Wizard of Oz?) But plenty of plants produce toxins like cyanide to keep themselves from being eaten. A quick Google search for “cyanide grass” and a quick peak on pubmed for cyanide poisoning shows a few interesting things, among them: “Southeastern plants toxic to ruminants: Selected toxic plants affecting cattle, sheep, and goats in the southeastern United States are presented…” (I really hate paywalls on journals, by the way.)

For cyanide specifically, I know that some seeds (like apple seeds) contain trace amounts. It’s not unnatural for plants to produce these types of compounds. Skim through — there are plenty of plants that rank right up there with things I’d suggest skipping. (Anyone know the writers for House M.D.? They should check out a plant called white snakeroot: cows can tolerate eating it but the milk they then yield can kill humans.)

Did the grass that killed these cows produce levels of cyanide-based toxins on par with what other poisonous wild plants produce? I.e. are we dealing with a true horror flick here, where a new Big Bad has come to town that we’re gonna need help slaying? And a follow-up question, does any common grass normally produce cyanide, but at such low levels that there’s no impact? (“Dosage matters!”)

What is Tifton 85? How was it made? All plants are capable of cross-breeding and mutating. From reading online, Tifton 85 is a crossbreed (good ol’ fashion breeding, just like Mom and Pop used to make) between “a South African grass and Tifton 68.” I can’t find much about Tifton 68, which has been around since at least 1984, possibly longer. (By the way, Tifton grasses are breed and created by the United States Department of Agriculture research station in Tifton, Georgia; the number refers the to the specific variant; so higher numbers are newer.)

Is there something specific about Tifton 85 or the GM process used to make it that lead to the mutation? I believe a lot of viewers will see the phrase “GM grass” and automatically assume that it’s the “GM” aspects that caused the grass to mutate. But based on the dates for Tifton 68, I’m not even sure that Tifton grass could be GM in the modern sense; i.e. more than just conventional cr0ss-breeding. (Yes, cross-breeding changes the genes. Just like your genes are a combination from your two parents.) If Tifton 85’s lineage consists of only crossbreeding, then I think it’s unfair to call it “GM Grass”, as the common usage of GM has come to mean genetically engineered (“things that could never happen in Nature”). Do you think that this is a fair distinction?

Other questions you want answers to? Anwers and critiques to my notes, of course, also appreciated.

P.S. If you’ve not seen Just Label It, check out