Rattlesnake venom is hemotoxic, meaning it destroys red blood cells as well as other body tissues.
gan administering fluids in a slow drip. Fancy would be unable to drink on her own until the swelling in her head diminished, and dehydration can be a fatal complication.
To combat the effects of the snake venom, Judd administered a liter of snake antivenin, produced from the hyperimmune plasma of other horses. Rattlesnake venom is hemotoxic, meaning it destroys red blood cells as well as other body tissues. It also disrupts blood clotting and, if the dose of toxin is large enough, can do enough damage to cause organ failure. Hyperimmune plasma is drawn from the blood of horses who have high levels of antibodies to the snake venom. When administered to a recently bitten horse, the antibodies in the hyperimmune plasma bind with and neutralize any toxins that are still circulating in the bloodstream. However, this treatment cannot “undo” any damage the toxins have already done. For that reason, antivenin is most effective when given soon after the bite occurs.
Ezell could not know exactly when Fancy had been bitten, but she and Judd opted to use the antivenin anyway, in
INFLATED: The biggest risk to snakebitten horses is swelling of the head. Fancy already had one nostril obstructed when she arrived at the referral clinic.
case it might still be able to do some good.
Fancy’s head remained grotesquely swollen, but the mare was beginning to look a bit more comfortable. All anyone could do for her now was to watch and wait to see how well she would recover as the venom would continue to affect her system. The mare would need to be monitored roundthe-clock for several days to watch for potential cardiac or neurological complications or other signs of damage to internal organs. The site of the bite would also need to be watched for signs of infection or necrosis (tissue death).
“A horse in this condition really needs to be watched 24-7 for several days,” says Judd. “If that’s your only job you can do it, but neither of us was in that position.”
Ezell and Judd decided to refer Fancy to a larger veterinary clinic, Brazos Valley Equine Hospital (BVEH) in Salado, Texas, which had the staff to provide the constant attention the mare needed. Once Fancy was on her way, Ezell got the rest of her morning back on track.
Supportive care
“The mare was stable when she arrived,” says John C. Janicek, DVM, who took over Fancy’s case at BVEH, “and doing pretty well, considering she’d been bitten in the head by a snake.”
Air was passing through Fancy’s right nostril, but swelling had blocked the left. Janicek disassembled a large syringe and inserted the barrel into her still-open nostril. With that tube in place, Fancy would still be able to breathe even if the swelling progressed.
Fancy was well hydrated with strong vital signs. The distance of the bite from any major organs was helpful, says Janicek. “So often the small animals are bitten on the torso or legs and they will go into respiratory and heart failure right away. The sheer size of horses not only dilutes the venom, but keeps it from reaching the major organs as easily.” As for Fancy’s mental outlook, he adds, “I wouldn’t say she was happy, but she was bright and alert.”
The state of Fancy’s left eye, hidden underneath the tightly swollen lid, was a significant concern. “We were worried about what damage there might have been to the cornea,” says Janicek, “but at that point it was still too swollen to examine. However, you could tell that the globe/anterior chamber were still normally inflated.”