Droughts and sandy soil: A recipe for disaster

August 30, 2018
Bo Brock, DVM

Bo Brock, DVM, owns Brock Veterinary Clinic in Lamesa, Texas. His latest book is Crowded in the Middle of Nowhere: Tales of Humor and Healing From Rural America.

As a freshly minted veterinarian Dr. Brock learned a lot about bovine toxicology.


It's been a long, hot, dry summer in Lamesa, Texas. Until last night we'd received only 2.5 inches of rain all year with 40 days over 100 degrees. I've lived in Lamesa for nearly 30 years and I've seen this weather pattern before.

The year after I moved here we had a drought similar to the one we're experiencing now. One smoking hot Thursday afternoon I got a call from a local rancher. His voice was desperate as he told me what was happening on his ranch.

One of his pastures was home to about 150 cows, and what this man described sounded more like a bad horror movie than a cattle ranch in West Texas. I listened intently for a few minutes and then told him I'd be there as fast as I could.

I was still fairly new to the area and was a whopping 29 years old. What I saw as I came over the hill made my jaw drop and brought a tear to my eye.

Twenty or so cows were standing belly-deep in the watering tank, slobbering and bellowing mournfully. Scattered on the bank around the tank were about 75 dead cows, and another 25 were doing strange things next to the water.

One cow was standing with its left front leg planted firmly on the ground and was spinning in circles with its other three legs. It had paced out a deep circle, and the pivot leg was a good 10 inches deep in the hole it had worn into the dirt. Two other cows were standing with their necks arched, looking as straight up as a cow can possibly look. One was pawing at her mouth with her front legs and had slobber pouring out of her mouth.

Piles of diarrhea covered the bank of the pond and almost as many piles of slobber. Three of the cows I had previously assumed were dead suddenly came to life and had seizures of astronomical proportions. One cow jumped up post-seizure and ran headlong into a tree like she never even saw it.

As I pulled up next to the owner in his pickup, he rolled down the window and told me not to get out. He said there were four or five cows running around that would attack you if they saw you. Two cows on the bank were knuckled over on all four legs and standing on the top of their fetlocks.

I needed to use a lifeline to call some folks smarter than me. I had a bag phone back then-you remember these things; they were the size of a regular old-timey house phone, just in a bag. I drove to the top of a hill and began making calls. One after another, smart people verified my worries-it was salt toxicity.

Over the next few days it all came together. The water was tested and found to have roughly 20 times more salt and sulfates than the ocean. You may wonder why the other three pastures on this ranch weren't having the same problem. That's an interesting story.

The rancher had a well up on the caprock, and he'd piped water down to one tank in each of his four pastures. This was done to ensure that each pasture would always have water even if it didn't rain. All of the pastures except the one with the dead cows in it had at least two tanks.

The drought that year was bad, but the other three pastures still had water in the tanks that were not receiving water from the well. This prompted me to test the water coming from the well and, sure enough, it was terrible.

The rancher couldn't believe it. He'd had the water from the well tested two years earlier and it had been wonderful. How could underground well water go bad in such a short time? I was on a mission to find out.

I called people from everywhere I could think of and finally found a fella at a university who had the answer.

We live in an area with sandy soil. We are also very flat. When it does rain, the water stacks up in large areas called playa lakes. These things can cover two or three square miles when large rains come, and then they evaporate and sink into the ground and may be gone for years until another big rain comes.

As these lakes evaporate, salt that has washed in from the surrounding soil becomes concentrated. And since the soil is so sandy, the now highly concentrated saltwater leaches down into the aquifer, resulting in good water becoming toxic. It's a natural process that the university guy says happens in our area once every 25 or 30 years when we have a year of big rains followed by a hot, dry year.

We slowly introduced the cows in the pasture that were still alive to fresh water. If you give it to them too fast, it will kill them. That rancher stayed with the surviving cattle 24 hours a day, giving them small quantities of water hourly until they were rehydrated. There is no other treatment than this.

I've learned a lot over the last 30 years, and I've taught every producer in our area about saltwater toxicity. We haven't had another case since then.

Bo Brock, DVM, owns Brock Veterinary Clinic in Lamesa, Texas. His latest book is Crowded in the Middle of Nowhere: Tales of Humor and Healing From Rural America.