Azoturia mainly affects stabled horses and occurs most commonly during the winter months when fields are unfit for turn-out and exercise is restricted due to icy surfaces and lack of daylight hours.

The condition is also known as; tying-up, set-fast or more correctly, equine rhabdomyolysis syndrome. It is a frightening, rapid onset condition which happens while a horse is being exercised and is best compared with muscle cramp in people.

Symptoms

Your horse may abruptly appear unwilling to go forward; he might take short, pottery steps and feel stiff or unsteady behind. In extreme, (and thankfully rare), cases the horse may seize up completely and be unable to move at all.

On physical examination, the horse’s hindquarters may feel hot and hard, and he will appear uncomfortable and distressed. If severely affected, the horse may collapse and be unable to get up again and his condition can easily be mistaken for colic.

Azoturia causes acute muscle pain. The horse’s body responds by elevating his pulse and his temperature. He may try to urinate frequently but will struggle to adopt the usual stance to stale and if muscle damage is severe, his urine may appear reddish-brown or dark chocolate in colour.

Action

Put yourself in your horse’s position; if you had severe cramp, would you want to keep moving? You would not and you should not insist that your horse does.

If you are riding at home or nearby, put your horse into a stable and offer him a drink. Make sure he has a thick, dry bed in case he wants to lie down and allow him to do so. Don’t pester him to stand up again as this will only stress him out even more. In thankfully rare cases the horse is completely unable to move. If he collapses and is obviously unable to rise contact your vet immediately, requesting emergency attention.

If you’re a distance away from home, stop; dismount and allow your horse to rest. Under no circumstances should you try to force him to keep going as to do so would risk causing him severe muscle damage. Try to arrange for a lorry to transport your horse home. A lorry is best as it requires less effort from the horse to stand than a trailer. A trailer will require him to brace himself more which will inflict more discomfort on already sore muscles.

It is very important to keep the horse’s seized muscles warm so place rugs or, if nothing else is available, your coat over his back to keep him warm.

Fluid intake is very important too in order to flush out the kidneys and thus reduce complications which could potentially arise from muscle breakdown so encourage your horse to drink if he will. Observe the horse to see if he is able to urinate normally. If he is struggling to go and his urine is very dark in colour, call your vet immediately.

Your horse will be in considerable discomfort and will therefore be stressed. It may help him to relax if you offer him a haynet to nibble on, but on no account give him any form of concentrates.

Prevention and prognosis

Unfortunately, once a horse has had an episode of azoturia, it is likely to experience another. Discuss how best to manage your horse in the future with your vet and seek advice from a specialist equine nutritionist as to the best feeding regime for your horse. Many large feed manufacturers employ nutritionists who are contactable through the company’s website or by telephone and they will happily give you qualified advice for free.

As regards to the prevention of azoturia, the old maxim; “increase the workload before you increase the feed”, holds true. The problem is typically caused by horses being overfed for the amount of work they are doing, although some animals are more prone to the condition than others.

Be on your guard during this spell of bad weather and make sure that you reduce your horse’s concentrate ration in direct proportion to the amount of work he is doing, particularly if he is spending more time than usual in his stable. Make sure you feed plenty of forage to keep him feeling full and prevent boredom and pad out hard feed rations with high fibre chaff and plenty of carrots so that he doesn’t feel too hard done by at feeding time.