What is Azoturia?
Horses that are rested for a period of time after a regimen of work or exercise are more at risk of developing azoturia, especially if feed intake has not been reduced during periods of rest. Horses of any age can be affected, but it is more common in mares and fillies.
Azoturia in horses is known by several different names including Monday morning disease, tying-up, set-fast, and equine rhabdomyolysis syndrome or ERS. It is best described as severe muscle cramps affecting the hindquarters and back of your horse. This causes stiffness and extreme pain.
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Symptoms of Azoturia in Horses
Be sure to thoroughly go over your horse after a period of rest and watch for any changes in behavior. Your horse will tell you if there is something wrong. If you notice any of these symptoms, contact your veterinarian for an assessment.
- Unwilling to walk
- Taking short steps
- Unsteady or stiff on hindquarters
- Muscles feel hard or hot to the touch in the hindquarters
- Cannot move, muscles seized up
- Unable to stand or collapses when trying to move
- Distressed behavior such as excessive head throwing or pawing the ground
- Raised pulse rate
- Reddish-brown or dark chocolate colored urine
- Frequent urination or frequent attempts to urinate
- Slight elevation in body temperature
Causes of Azoturia in Horses
The most common cause of azoturia is over-feeding an active horse during times of rest, such as feeding the same amount of food to a horse that is being stalled for a day or two instead of cutting rations to accommodate the lack of activity. Too many carbohydrates can cause the muscles to have an acid base imbalance and can cause muscle damage if severe enough.
Over-feeding is not the only cause of azoturia. Since fillies and mares are more at risk, a hormonal imbalance has been suggested as an underlying cause. A thyroid imbalance has also been determined as a cause of azoturia. Researchers have also found a link between azoturia and a deficiency of selenium, vitamin E and calcium.
Diagnosis of Azoturia in Horses
Your veterinarian will complete a full physical examination of your horse and may draw blood for a CBC to rule out other possible diseases. A complete medical history of your horse, as well as daily routines, will also be helpful when diagnosing azoturia. Since azoturia can closely mimic colic, it is important that you give detailed accounting of all recent activity, type of feed, and amounts of feed given.
Your veterinarian will also do a muscle biopsy from the muscles just to the side of the tail, the semimembranosus or semitendinosus muscles. The biopsy will determine if there are excessive proteins within the muscles, indicating that your horse is suffering from azoturia.
Treatment of Azoturia in Horses
Once it has been determined that your horse is suffering from azoturia, your veterinarian will give you detailed instructions on caring for your horse.
Keep your horse calm and allow them to rest, preferably in their own stall. Keep the hindquarters warm by putting a coat or blanket over them. Put some hay out for your horse. Eating can calm a horse, just do not give any feed that is carbohydrate based.
Encourage re-hydration by offering clean, fresh water often. Keep an eye on how often your horse urinates and if the color is not normal. If you notice extremely dark urine, contact your veterinarian for another assessment as there could be an underlying cause that was not diagnosed.
In cases of azoturia where nutrient deficiencies are present, your veterinarian may prescribe a special nutrient rich food for your horse. In some cases, vitamin injections may be necessary.
Contact your veterinarian if there are any changes in your horse’s condition, especially if your horse refuses to stand or their behavior becomes more and more agitated.
Recovery of Azoturia in Horses
Once your horse has been diagnosed with azoturia, they can become more susceptible to it. Discuss a management plan with your veterinarian to minimize the risk of a recurrence.
Most horses make a full recovery when given proper treatment and a lot of TLC. Following treatment plans and being vigilant will help your horse recover without any muscle damage or other permanent damage. There are instances when a veterinarian was not called in time. In these cases, severe muscle damage has occurred and the horse will have to be put down.