It's something you wouldn't believe could happen unless you saw it. You walk out to the barn in the morning and start to panic when you realize your horse has cast itself. Somehow, someway, your horse has managed to lie up against a wall and is unable to get its feet underneath it to stand up. Most horse owners know their equine companions can't lie down for long, but exactly why that is remains a mystery to many.
"The longer they are down, the more prone they are to reperfusion injury," says Dr. Elysia Schaefer, an equine surgery resident at the University of Illinois College of Veterinary Medicine. Reperfusion injury can happen because horses are such large animals and the weight of their body in and of itself can prevent blood flow to certain locations. This can cause severe problems when they try to stand up again, and blood flow tries to return to normal.
Because Dr. Schaefer frequently deals with equine patients that must remain on their backs for an extended period of time during surgery, she knows time is of the essence in the operating room. While surgeries in smaller patients, including humans, may go on for countless hours, equine surgeons usually have a window of about three hours to get the job done.
After surgery, "We usually give them around one to two hours in the recovery stall and let them try and stand on their own," explains Dr. Schaefer. At the Veterinary Teaching Hospital in Urbana, the large animal surgery recovery room is covered from wall to wall with soft blue pads, and the floor is an inflatable mattress to better comfort patients coming out of anesthesia.
Whether a horse is down because of surgery or it has cast itself in a stall, there are several problems that can occur. Besides reperfusion injury, muscles on the down side of the animal, as well as nerves, can become damaged from excessive pressure. Also, the "down" lung of the horse may cause trouble as excess blood pools there due to gravity.
Horses with neurological diseases are occasionally referred to the teaching hospital for intensive care. In some of these cases, the animal cannot stand. "With neurological cases where the patient is down, we are very careful to go in and flip them every few hours," says Dr. Schaefer. Although an equine surgeon worries about several issues if their patient were to be on one side for a long time, horses can get bedsores just like humans too.
While there is no hard and fast rule about how long a horse can be down before permanent damages ensue, the sooner you can get them up the better. Some owners think it is beneficial to pile wood shavings at least two feet high around the perimeter of the stall to prevent casting. However, that isn't fool proof.
If your horse has been down for a long period of time, or it is has cast itself and you are concerned with its health, call your veterinarian. Some horses may be very scared if they can't get up on their own so use extreme caution if you try to move them.