Tuesday, June 14, 2011

Heather Smith Thomas: Notes from Sky Range Ranch — Snakebite!, Part One: Personal Experiences With Our Animals

Our dry western hills harbor several kinds of rattlesnakes, and now and then one of our animals is bitten. Over the past 56 years on our family ranch several dogs, a cat, one horse, and numerous cows and calves have suffered snakebite. Fortunately, the snakes here in central Idaho are not very large — the biggest ones are only about 3 feet long — and their bites aren't as deadly as that of a large diamondback or sidewinder. The diamondback of eastern Oregon and Nevada and the sidewinder in the desert Southwest can inject much more venom.
The rattlesnakes in our area are not very large. This one,
killed in our driveway next to our house, was about 2.5 feet long.
According to my high school biology teacher, Terry Armstrong, who studied snakes, the rattlesnake is the most common type of poisonous snake in the United States. This snake belongs to a group called pit vipers, which includes the water moccasin, cottonmouth, and copperhead. There are many subspecies of rattlesnake, varying greatly in size and length. Here in eastern Idaho, Armstrong identified three kinds — the prairie rattler, the Great Basin rattler, and the Pacific rattler.
The danger or potency of a snakebite depends upon the amount of venom injected into the victim. A large snake that hasn't killed prey recently, with a full pouch of venom, is more deadly than a small snake or one that has recently eaten. The rattlesnake catches its food (usually small rodents) by biting them; the venom attacks the nervous system. The venom of the pit viper contains two types of toxin, neurotoxin and hematoxin. The latter creates severe and rapid swelling at the site of the bite. A very small animal such as a mouse or chipmunk is paralyzed by the neurotoxin and dies within seconds or minutes, enabling the snake to eat it.
This snake is coiled and ready to strike —
— with buzzing rattles to warn away predators or animals that might step on it.
The poison's effectiveness is in direct relationship to the size of the animal; a small dog, cat, or child may be seriously affected, whereas a large animal such as a horse or cow will usually survive the bite unless serious infection develops or swelling on the face results in suffocation from constricted airways.
The bite causes pain, tissue damage, and swelling. In a small animal neurotoxins in venom cause convulsions, muscle paralysis, and subsequent death because the muscles needed for breathing stop working. In a large animal the damage is local; the poison isn't strong enough to get very far. The circulatory system may carry it a ways, however, and this is why a bite victim should be kept quiet; increased circulation from exertion can spread the poison and cause more problems.
Bites on the legs of a cow or horse are not as dangerous as bites on the face. Venom from a bite on the lower leg rarely gets into the circulatory system. There may be local pain and swelling or no symptoms at all if the snake strikes the leg bone and venom does not get into the soft tissues.
My young horse Khamette was snakebitten when I was a teenager.
She had no ill effects — except for an abiding fear of snakes from that time onward.
When I was a teenager, one of my horses — Khamette — was bitten on the front leg. We could see the fang marks, but except for temporary local swelling it didn’t bother her much at all. She was mildly lame for a few days until the swelling disappeared. Until that point she had no fear of snakes (none of our ranch horses did — they never shied away from the sound of the rattles). After being bitten, however, she’d always jump away from the sound of a rattlesnake. If the person riding her was caught off guard, she’d nearly jump out from underneath her rider and might leave him or her on the ground by the snake!
The biggest danger from snakebite in a large animal is swelling, if the bite is on the face. Unless found and treated quickly, a horse or cow that is bitten on the nose may die within a few hours, of suffocation. Some friends of ours lost a young horse one summer from a bite on the nose. Horses and cattle (and dogs) are curious and sometimes are attracted to the sound of the snake.
The calf we brought home from the range to treat for snakebite
One of our calves on summer range a few years ago was bitten in the face, and the resultant swelling made it hard for her to breathe. Her breathing was so labored that we were afraid to try to catch her for treatment. The exertion of moving, and the subsequent increased need for oxygen, would probably have killed her.
Fortunately, the calf was near a water trough, and she spent most of her time trying to sip cold water from the in pipe. Her throat was almost swollen shut, and she was unable to nurse her mother, but she managed to sip water. After a day of standing by the trough trying to drink cold water, the swelling on her face was reduced by the cooling effect of the water on the swollen tissues. She survived and recovered.
Another calf was bitten the next year on the lower jaw, and we were able to bring her home for treatment, since her breathing was not impaired. We put her in the chute and gave her DMSO to reduce the swelling and antibiotics to combat any infection.
We've treated a number of animals, but the worst case was a cow named Jana. She was apparently bitten on the side of the face while grazing. When I found her during one of my rides to check cattle that fall, she was very ill. I slowly herded her home — a 2-mile trek — so we could treat her. She had a fever of 107 degrees when we took her temperature; her face was swollen from mouth to eye on that side; and the swelling had sealed off the salivary ducts, trapping saliva in the tissues of the mouth. This created a large balloon of fluid under her tongue, and she was unable to eat. The tear ducts of the eye on that side were also obstructed; that eye was swollen shut and oozing thick mucus. At least she could breathe, and this was the only reason she’d survived long enough for me to find her.
Our cow Jana developed serious infection and multiple abscesses
in the swelling on the side of her face . . .
. . . and I flushed those out daily with antiseptic solution.
We treated her for infection for several weeks and feared that she might abort because of the high fever. She didn’t, but when her time came to calve the next spring, she gave birth to a small, mummified fetus. The high fever had indeed killed her calf; the mummy was the size of a 6-month fetus — which corresponded to the stage of pregnancy when Jana was bitten.
A few years later we had another cow bitten on the shoulder when she was in a steep rocky pasture. Probably, she walked past a rock ledge where the snake was resting, and as it struck it would have hit her at shoulder height. We noticed a large lump on her shoulder, but she wasn’t ill. We weren’t actually sure it was a snakebite until about a week later when all the hair came off the lump and the fang marks became visible. That cow recovered without treatment.
[to be continued]
Heather Smith Thomas raises horses and cattle on her family ranch in Salmon, Idaho. She writes for numerous horse magazines and is the author of several books on horses and cattle farming, including Storey’s Guide to Raising Horses, Storey's Guide to Training Horses, Stable Smarts, The Horse Conformation Handbook, Your Calf, Getting Started with Beef and Dairy Cattle, Storey's Guide to Raising Beef Cattle, Essential Guide to Calving, and The Cattle Health Handbook.

You can read all her
Notes From Sky Range Ranch here.

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