All Tied Up...
by Linda Kennard NAF
Azorturia, Equine Rhabdom-yolysis Syndrome, Monday Morning Disease, Tying Up are all terminology for the multifunctional myopathy in horses.
This winter there appears to have been an increase in the number of horses suffering from this condition. Whilst there are a number of predisposing factors that could lead to an attack, the recent increase in cases could well be due to the extremely wet weather conditions.
The very wet grass will have a much higher moisture content than normal for the time of year which means the fibre content will be lower. High levels of fibre in the diet is vital for the gut health for azoturia horses.
Rain fall leaches nutrients from the soil. Many areas are known to be selenium deficient, due to acidic soil and high rainfall. Therefore, as areas of high rainfall are more extensive, it is possible that the selenium deficiency is more widely spread than normal.
Wet ground reduces the amount of exercise for a lot of horses. This can leave them standing in the box for longer periods of time, creating ideal conditions for azoturia, especially if feed is not reduced.
There are a number of other predisposing and triggering factors that can lead to azoturia which also need to be considered, including:
High starch diets
Hormonal disturbances
Dehydration and fatigue
Viral infection
Not warming up or cooling down sufficiently when exercising
Electrolyte imbalance
What happens when the horse suffers an attack of azoturia?
The outer cell membranes start to leak, allowing the loss of two enzymes, Creatine Kinase and Aspartate Aminotransferase. As these enzymes are released their concentration increases in the blood. If the damage to the cells is severe, a muscle pigment, Myoglobin may also be released into the blood. Myoglobin is excreted via the kidney and will discolour urine.
This muscle damage causes lactic acid to be released, leading to muscle cramp and pain. The severity of the symptoms varies enormously - from what will appear as a slight stiffness to complete seizure of the muscle and immobility. Severe cases may include signs of severe pain with accompanied by sweating, increased pulse rate, increased respiration rate and immobility. Continuing to work a horse that is mildly affected can considerably increase the degree of muscle damage and pain. Therefore if azoturia is remotely suspected work should stop immediately.
As always prevention is better than cure
Prevention is all-important therefore careful attention to diet and management is required. The muscle damage is caused by a build up of toxins and these breakdown the cell wall. Antioxidants are natural extracts with the ability to flush toxins from the system. Antioxidants are recommended for horses who are prone to azorturia. Ideally the antioxidants should be combined with nutrients for repair of muscle cells, such as bioavailable sulphur which is vital to amino acids. Yeast is also recommended through peak periods, to maintain the digestive equilibrium and help prevent the cascade of toxins that trigger an attack of azoturia.
