A few summers ago, I was called out to a dairy farm to perform a necropsy (animal autopsy) on a cow that was found dead in the field. Although this wasn’t the first time I was called out to try to determine cause of death in an animal, the circumstances were a little unusual, as my necropsy would be submitted for an insurance claim because it was suspected the animal died from lightning strike.

 

I always thought of lightning strike as something that happened back in the days of the wild west, when farmers not only had to worry about weather but also cattle rustlers and train robbers. Although train robbers may now be a thing of the past, farmers still worry about the weather (and there are still some cattle rustlers out there, too). 

 

Where there are large ranges and thunderstorms, there will always be the chance of lightning, which, I suppose, is why some farmers have their herds insured against it.

 

Most farm animals that die from lightning do so via ground current, or when lightning strikes a tree and the electricity continues to run along the ground, affecting animals standing near it.

 

When determining if an animal has died from lightning strike, environmental clues can help. Certainly knowledge of a recent thunderstorm is most helpful, as is finding the body near a large tree. Sometimes entire groups of animals are killed, which happened in Chile earlier this spring when over 60 cows died during a storm. Photos from this event show a group of animals next to a tree in an otherwise open field.

 

Physical indications that an animal has died from lightning strike are often not as apparent as you would think. In the case of my dairy cow, there were actually no outward physical indications of this cause of death and I went mostly on the environmental clues mentioned above. In other cases, singed hair and burn marks on the hooves will indicate lightning strike, but almost paradoxically these findings are rare.

 

Animals die from lightning either through immediate destruction of the nervous system or from cardiac arrest. Although it’s been said that lightning strike victims will bloat faster than in other causes of death, since the exact time of death is usually unknown (and I walk into the situation 12 to 24 hours later), this fact doesn’t really help me during my post-mortem examination.

 

Horses, too, can fall victim to the weather. Lightning strike is a common cause of death for mustangs roaming out west; the flat terrain at higher elevations is frequently struck by lightning and if a horse is the highest thing around, he becomes a conductor to the ground. I myself have not yet seen an equine victim of lightning in the mid-Atlantic, although I’m sure it’s not unheard of.

 

There are a few things a farmer can do to help protect his herd from lightning. One is to make sure barns and sheds are properly grounded. Another thing is to arrange pastures so that they contain rows of trees, not singles. Lightning is more likely to strike one large tree as opposed to a group, although this is not in any sense a rule. And at the very least – don’t place a metal water trough at the top of a hill!

 

I’m not sure what the payout from the insurance company was for the struck cow but that case made me realize that despite all our technology in the 21st century, weather risks in farming never change.

 

Dr. Anna O'Brien

 

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