Azoturia in horses

Azoturia is a muscle disease with typical symptoms, which are hard for horse owners to miss. It is a serious condition, and sometimes affected horses have to be euthanised.

What are the symptoms?

• Stiff gait
• Reluctance to move
• Swollen, hard hind leg muscles
• Pain when pressure is applied to the muscles in the hind legs
• Sweating
• Increased breathing rate (normal breathing rate at rest is 8-16 breaths per minute)
• Increased heart rate (normal resting heart rate is 28-40 beats per minute)
• Red coloured urine
• Your horse insists on laying down

What causes Azoturia in horses?

The classic Azoturia occurred in heavy work horses that were started after a weekend rest with maintained forage. This is how it got the nickname "Monday sickness". It is still common for the disease to affect horses that are trained after they have rested for a day or two.

Another trigger is uneven training or different types of stress, such as transporting your horse. The exact mechanism behind the disease is not known, but it is believed that a factor in the horse can make them susceptible to Azoturia.

In the case of Azoturia, muscle damage occurs, especially in the hind leg muscles. The extent of the damage can be measured through blood tests. The enzymes AST and CK are normally found in the muscle cells, but in the case of Azoturia the cells break down, AST and CK leak into the bloodstream and a blood test will show elevated values.

The stronger the Azoturia, the higher the values ​​that can be measured. The muscle cells also contain myoglobin, a substance that takes up oxygen from the blood and gives the muscles their red colour. It's the myoglobin from the damaged muscle cells that sometimes causes the urine to be coloured dark red.

Consequences of Azoturia

Mild attacks cause mild muscle damage that can heal quickly, without causing lasting discomfort. A severe attack can cause more extensive muscle damage that can be permanent, because some muscle cells are replaced by scar tissue. The formation of scar tissue can lead to the muscle not working as before, giving your horse a permanent movement disorder.

How is usability affected?

Most horses affected by Azoturia recover and can be used as before. In order to avoid relapse in the future, it is important to review the feed state and that training is regular. Individual horses suffer such extensive injuries that it will affect their performance in the future. Really strong attacks can lead to the horse having to be euthanised urgently.

How do I prevent Azoturia?

Physiology

It's suspected that there is some predisposing factor in the horses that suffer from Azoturia - something in the horse that makes it susceptible. Therefore, it is often only one individual in a stable that gets it, even if all horses are handled, trained and fed in the same way.

Young horses that suffer from Azoturia run a greater risk of being affected again than older horses. The attacks usually become less severe with age. Mares suffer more often than stallions and geldings, it is not yet known why.

Environment

Daily outings in large paddocks give the horse an opportunity to move on its own. This makes it less sensitive to possible breaks in training and therefore reduces the risk of Azoturia in horses that are sensitive.

Feeding

Maintained feed state even though the horse is resting can cause Azoturia when the horse is started again. Therefore, it is important to reduce the concentrate feed if your horse has to rest for a few days.

This applies above all if your horse receives a lot of concentrated feed and is especially important if the horse is not allowed to go to pasture. When you start the horse again, you gradually increase the amount of concentrate. If for some reason your horse is forced to box rest for a period of time, it may sometimes be necessary to remove the concentrate completely.

Do not overfeed either with energy or with protein. To avoid this, it is necessary to calculate the feed balance and to have analysed the roughage.

Check your horse is getting enough selenium and vitamin E in the forage. Selenium and vitamin E are needed to heal injuries that have occurred and seem to be able to prevent paraplegia to some extent. Selenium and vitamin E are toxic in too high a dose, it is important not to overdose.

Handling and use

All horses feel good from regular exercise and it can help prevent Azoturia in horses that are sensitive to it.

Prevent your horse from getting chilled - a horse that gets chilled stands and tenses up. The tensions can lead to soreness in the muscles and affect your horse negatively when they have to work. Let them wear a blanket in the paddock when the weather requires it, especially if it is damp and very windy. Also put a blanket on after a training session when the horse has become sweaty.

It is uncertain whether cooling has any effect on the onset of Azoturia, but it should be avoided just to be safe.

Important:

The symptoms of Azoturia vary from individual to individual and usually appear when your horse is exerted, but it's possible they only get symptoms afterwards. The faster the symptoms appear, the more severe the attack usually becomes. Some horses show a slight stiffness after exertion, others show symptoms such as reluctance to move, abnormal sweating and a sharp increase in heart rate and breathing during the session.

If you are not attentive and immediately let your horse rest, the symptoms worsen. Your horse will find it increasingly difficult to move, pulse and breathing increase and it starts to sweat. If you feel the musculature in the hind legs, it feels swollen and hard. If a horse becomes acutely ill and quickly unwilling to move, it should be allowed to remain where it is and not forced to move further, as this can worsen the condition and in the worst case cause the horse to lie down. If your horse lies down, the prognosis is much worse. Recumbent horses easily sustain additional muscle damage from their own weight, especially if they have difficulty moving. It significantly reduces its chances of being able to rise.

What should I do?

• Immediately stop any form of exercise or training if your horse shows symptoms of Azoturia. If the symptoms are due to a stretch or similar, it is positive to move your horse, but if you suspect Azoturia, you should refrain, because movement aggravates the muscle damage.
• Prevent your horse from getting cold. Put a blanket over it if it's sweaty and continue to keep the muscles warm.
• Let a horse that has become recumbent remain. Make sure it lies softly to prevent pressure damage. Do not force it to stand up - further effort leads to further muscle damage and worsens the situation.
• Make sure your horse has free access to water.
• Contact a veterinarian for examination and treatment.
• In the case of mild attacks, where it is certain that it is a case of Azoturia, it is not certain that the vet needs to come out. However, it can be good to consult by telephone.
• Avoid transporting your horse. Transport is a stress for them, and can worsen the Azoturia.
• Review the feed state. Give only roughage and water to begin with and slowly introduce other feed. Avoid overfeeding protein and energy. Make sure that the basis of the feed state is a good forage and that the mineral balance is correct.
• Give supplements of selenium and vitamin E. They contribute to the healing of the muscle damage.
• Be careful not to overdose, as the substances are toxic in too high a dose. Both selenium and vitamin E are usually found as supplements in mineral feed, in ready feed mixes and pelleted feed. Read the packaging carefully so that the total amount is not too large.
• Give vitamin B. B vitamins are water-soluble and cannot be stored in your horse. Any excess is peed out. Therefore, there is no need to be afraid of overdose. B vitamins are considered to have a positive effect on the healing of muscle injuries.
• If your horse is very stiff after an attack of Azoturia, they should be allowed to walk alone in a small paddock without other horses until they recover.

What will a vet do?

Your vet will want to know as much as possible about your horse's past medical history, as well as how the horse has been cared for, trained and fed recently. When examining the horse, the veterinarian looks at how the horse moves, feels the muscles and examines breathing and heart rate. In suspected Azoturia, a blood test is also usually taken to examine the extent of the muscle damage.

To reduce the pain and stiffness, it is common for the vet to give some type of anti-inflammatory medication against the swollen, sore muscles. Often the vet also gives vitamin B.

The acute stage is over, what should I do now?

Follow the treating veterinarian's advice on how your horse should be treated and trained after its illness. In order to avoid your horse being affected again, it is important to review the state of feed and training. By counting on the feed state, you can avoid unnecessary overfeeding and thereby reduce the risk of your horse suffering from Azoturia.