POISON ON THE FARM, Part II

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COUNTRY VET

A long day continues...

By Jon Geller,G.V.M

When last we left our country vet, he'd spent the morning ministering to to poisoned cows, goats, horses and pigs, and was racing toward the Caulfield Ranch to see about a sick dog...

12:30 P.M.

Colorado is known for its dry weather and today was no exception. I raced up the lane to the Caulfield Ranch, a plume of dust shadowing my truck. It overtook me just as I stepped out of the cab and noticed Bill Caulfield running up to greet me.

"Dr. Jon, thanks for coming on short notice. Sam is in the barn."

"When did he get sick?" I asked.

"Well, Sam always likes to ride on top of the hay bales when we bring them in. But this morning we noticed he didn't follow us out to the field. When I brought the first load into the barn, I found Sam more or less collapsed."

Sam was laid out on his side, breathing hard and fast. I checked his gums and found them a pale gray. Clearly, he was a very sick guy. I rolled Sam over onto his back, his abdomen appeared bloated and looked as if it was full of fluid. His heart was racing, and his pulse was weak—a sign of decreased blood volume. The heart was compensating for the loss of blood by pumping faster Sam was probably bleeding into his abdomen. I carefully inserted a 22-gauge needle into his abdomen, pulled back on the syringe and watched it fill with dark, red blood. It was time for action.

"Bill, you have some other dogs, don't you?"

"Sure, we have three other border collies."

"I need the biggest one of the bunch over here right now."

I didn't need to do any blood tests to know that Sam was gravely anemic. Fortunately, because he was bleeding into his abdomen, he was able to reabsorb some of the oxygen-carrying red cells.

My brain tends to shut down at times, which is why I bring my diagnostic software with me to help home in on the diagnosis. I grabbed my laptop from the truck and immediately noticed there was some congealed blood between the E and R on the keyboard, probably from one of the vials of blood I'd drawn from Helga Volkman's pigs. As I was about to pull up a list of causes of internal bleeding, it struck me that in veterinary medicine answers are often staring you in the face; you only need to open your eyes to see them. Sam's blood wasn't congealing properly.

Warfarin toxicity is the most common poisoning among dogs and cats. It occurs when animals ingest rodent poison containing warfarin or brodifacoum, or when they eat poisoned rodents.

Warfarin is an anticoagulant that interferes with the normal clotting of blood. It has a delayed effect, and a dog or cat that ingests an anticoagulant rodent poison may not show signs for two to ten days, depending on the half-life of the anticoagulant in the poison. Newer second-generation products such as D-Con Mouse Pruf II or Havoc are more potent, requiring a smaller dose to cause toxicity. Bill confirmed that some second-generation D-Con had been put out a week ago.

Bill brought over another border collie named Tess, who looked healthy enough. I clipped up her neck, gave it a few surgical scrubs and pulled about 150 ccs of blood. Immediately, I injected the transfused blood into a catheter in Sam's leg. Ideally, this blood would be given through a filtering system to remove any clots, but in this setting we had to improvise.

The blood transfusion gave Sam some clotting factors and red cells that he dearly needed, but he still required the antidote for warfarin poisoning: vitamin K. Vitamin K is an essential catalyst in the clotting process. Warfarin and other anticoagulants interfere with the action of vitamin K, preventing normal clotting and leading to spontaneous bleeding into body cavities.

If Sam survived the next 24 hours, there was a good chance he would be fine. The vitamin K would be given as an oral medication for the next two weeks. After dispensing the necessary capsules, I turned to Bill and said, "Here, let me write a prescription that may help with this problem in the future."

It read: Rx-One cat, adept at catching rodents. Refill as needed.

I got back in my truck, avidly anticipating a bite of lunch at the cafe down by the highway, perhaps followed by a short nap. But a check of my voice mail cured me of that notion: The Millers had a llama that had been down since this morning.

2:15 P.M.

The sick llama's name was Dolly, and I found her lying on her side next to the barn. She was salivating profusely, her pupils were very small and her heart rate was surprisingly slow. She was humming, as all llamas occasionally do, but clearly in a distressed sort of way.

"Doc, we found some lice on her yesterday and sprayed her with a solution they gave us at the feed store. Here's the container," Bill Miller explained, handing me a partly empty plastic spray bottle.

Dolly had been spritzed with chlorpyrifos an organophosphate compound. Organophosphates work exquisitely well to kill parasites of many types by interfering with nerve transmission, causing paralysis. When used carefully at the correct dose, they are safe for most livestock and pets. But as with other insecticides and pesticides, some individual animals are more sensitive. Llamas are particularly susceptible because owners frequently overestimate their weight and consequently overdose them.

All of Dolly's signs suggested organophosphate toxicity. Fortunately, there is a good antidote called atropine. Atropine blocks the effects of organophosphates at nerve junctions, so I gave Dolly an injection under her skin and left several more doses for the Millers to administer every five to six hours until Dolly was acting normally. Organophoshphate toxicity is completely reversible when treated correctly.

While we were waiting for the atropine to take effect, the Millers couldn't resist showing me some pictures of Dolly when she was a baby, or crea. When you work with llama owners, this is the sort of thing you come to expect.

By the time I had loaded up my supplies, the llama's pupils had dilated somewhat and she was salivating less. She was going to be fine. As I was pulling out from the Millers' barn, Bill Miller yelled out, "Hey Doc, why do llamas hum, anyway?"

"That's an easy one," I shouted back over the hum of the truck engine. "Because they don't know the words."

My mind shifted gears as I headed up the long hill leaving the Millers' place. I tried to recall, from my vet school years, the three principles of treatment for poisonings: 1) prevent further absorption, 2) provide supportive care and 3) provide an antidote, when known.