I (Nature) am called a mother, but I am a grave.
Alfred de Vigny
All sorts of oddities are being documented in the natural world, and I mentioned one to my brother, a veterinarian, on a recent phone call. His name is Wiley Heath, but his siblings know him as Biggy, and I will refer to him that way. Calling him Wiley would feel weird, and there is enough of that afoot.
Biggy lives in Clint, Texas, and I asked him if he had heard about the mysterious death of 100 elk on a private ranch north of Las Vegas, New Mexico. He hadn’t, and that led to a fascinating discussion. Biggy is kind of a Western character, a wonderful storyteller and humorist, and you might not realize right away how smart he is. Soon, however, I was reminded.
But back to the elk. A hunter had found them in late August on less than one square mile of a 75,000-acre ranch. They seem to have died within twenty-four hours. Tissue and water samples had been sent to diagnostic labs in New Mexico, Texas, and Georgia, and still there were no conclusions about what had happened. It is possible that a virus had killed them, but usually that takes days. They had not been eating the lichen that killed over 400 starving elk in Wyoming back in 2004.
The elk deaths reminded Biggy of a case he had handled just recently. A man who owned a feed store and kept 100 head of cattle had called him to say that six had inexplicably died overnight. Biggy went out to the place and took a rumen and an eyeball from one cow to examine. He also took a sample from a two-ton bail of sorghum the owner had just opened. He was speculating that the cows had suffered cyanide or nitrate poisoning from the feed, which had been shipped in from Arizona.
The tissue samples were sent overnight to Texas Diagnostic Labs, and soon Biggy had a report. The rumen, which is the first stomach of the cow and would have revealed cyanide poisoning, was negative. The aqueous humor from the eye contained an extremely toxic level of nitrates. The feed samples had six times a toxic dose of nitrates. It was the sorghum that had killed the cows.
Biggy talked with both the client and the farmer who had shipped the feed, and it seemed that neither had done anything wrong. The farmer said he would refund the payment but was really puzzled about what had happened, and Biggy proceeded to ferret out the answer.
There had been two types of bails shipped, both two-wire bails and two-ton bails. The first had been produced when the sorghum was suffering from drought and had grown only two feet high, and it did not harm the cattle. The two-ton bails had been collected after heavy rains and when the sorghum had grown four feet tall. It was the latter that had killed the cattle.
Biggy asked the farmer a number of questions. Did you fertilize the crop? No. Did you by any chance bail the second batch after the heavy rains? Why, yes, the farmer said, he had. The sorghum had undergone a tremendous spurt of growth and was lush and green. Nature’s bounty.
Then Biggy explained. In that sudden rush of growth after the rains, the sorghum had taken up an inordinate amount of nitrates. The nitrates in the soil are converted into nitrites in the animal’s body, and excessive amounts produce something called cyanmethemoglobin, which can’t transport oxygen. The cattle basically suffocate within three or four hours of ingesting the feed.
As Biggy talked I remembered that when I was learning about composting worms, I discovered that when rain falls, it captures nitrogen in the air. In the soil, it turns into a natural form of fertilizer, and that’s why everything turns green after a rain. That’s also why you don’t get a similar effect from watering with a hose. It’s just not the same.
So back to the elk. Prior to their deaths, heavy rains had stimulated fast-growing, rich grass in the Las Vegas area. Biggy wondered if it was overloaded with nitrates. Had anyone taken an elk eyeball to examine? The wildlife disease specialist quoted in the article speculated that runoff had washed something toxic into the water that the grass had taken up, but he said they might actually never know what had killed the animals. I will be watching the newspaper for followup.
This story certainly illuminates my brother’s detective skills, but it also reveals how little most of us know about how the natural world works. The farmer, for example, had been raising crops for fifteen years but wasn’t aware that the combination of intense drought and sudden, heavy rain could produce growth deadly to ruminants. He probably hadn’t been through that cycle before.
One definition of genius is extraordinary skills in observation, and certainly these enabled early man to survive under the most primitive conditions. This anecdote suggests that it may be time to tune up our gifts in observation, figure out what is coming in a rapidly changing environment, and prepare to mitigate the risk as much as possible.
Before we said goodbye, Biggy commented that he had seen a dying bee on the ground recently. For the first time.