A few weeks ago I came home from work and 1 mare was contorted indescribably in pain. I got her in the trailer and rushed her to the vet. Two vets were treating her and had no idea what was wrong with her. I had to leave her overnight. When I got home my other mare and gelding had the same symptoms just not as violent. All 3 were shaking uncontrollably in their HQs and couldn't stand for very long. The vet came out at midnight and tried to do something for them.
The next day they called the University of Tennessee vets and found out it could be botulism. There is no test for botulism you just have to treat it with anti-toxin, and if it goes away then it was botulism. UT was out of anti-toxin, so we had to wait for it to be shipped from the manufacturer. All I could do that night was sit and watch my horses dying.
They made it through the night and got the anti-toxin administered through I.V. The next day. That evening they were slightly improving. The vet came back the next day and administered the 2nd dose. They were MUCH improved by that evening. It has been a few weeks now, and they look like nothing ever happened.
The vet said they most likely got it from a round bale of hay. We have never fed our horses round bales. This was the first time. He said he never recommends round bales for horses--they are fine for cattle. We have never heard that before. Again, I think an adult horse getting botulism from hay is like getting struck by lightening so don't freak out.
Apparently botulism is common in foals, and they are referred to as "shaker foals" because the large muscles shake uncontrollably. I'm assuming because they are so small even a small amount of the toxin has a huge affect on them.
An important thing to know about botulism is the shaking is symetrical. If the horse is shaking in only one limb or one side of the body, then it's not botulism. Botulism always presents symetrically.
All is well on the ponderosa again I just wanted to share this story because I had never heard of botulism in horses, and thanks to the internet the word can spread and maybe help someone sometime.