There are several disorders of horse which can arise from through faulty feeding management. Some of these can result in severe lameness or death. This statement does not necessarily hold true for 100% of horses 100% of the time, however you may find that maybe one or more of your horses do suffer from time to time from the following conditions.
TYING UP
This condition is also called Monday Morning disease, Exertional Myopathy, or Myoglobinuria.
Tying-up typically happens when a horse is worked after a few weeks rest, without warming up, and after being fed a grain-rich diet during the rest period. It is not uncommon in pit ponies used in the Collinsville (Qld) mines in the 1930s/1940s period when untrained staff were used to look after the horses over the weekends.
There are two theories about why horses tie-up. the condition is certainly related to glycogen accumulation in the horse's muscles, but so far a reasonable explanation for why this happens is not clear.
The present evidence would suggest this-:
(i) Horses are very good at accumulating glycogen in their muscles - this means that if they are exposed to a 'carbohydrate loading' feed (high in cereal grains) they will overcompensate and store dangerous amounts of muscle glycogen.
(ii) Some horses are genetically predisposed to accumulating abnormal amounts of muscle polysaccharides. Of these, glycogen is only one example.
(iii) It is thought that muscle glycogen is oxidized as an energy source in the muscles of an inadequately warmed-up horse.
An earlier theory involved the build up of lactic acid, which may accumulate in the muscles for two reasons. 1. If a horse is not correctly warmed-up, inadequate blood flow through its muscles means that little oxygen is brought to the muscle and those muscles then forced to operate anaerobically. This is quite normal, but a lactic acid is formed under these conditions. Secondly, some muscle fibres (fast-twitch fibres) operate anaerobically anyway and the glycogen they use is converted to lactic acid, Muscle glycogen is normally recycled via the liver to glucose, but if large amounts are formed then this process may not work properly, It was thought that the lactic acid which accumulated in the muscles under these conditions simply acted as a relatively strong acid and damaged muscle tissue. This was then thought to cause the leakage of the muscle oxygen-carrying pigment (myoglobin) into the blood and eventually to its excretion in the urine. Evidence supporting this theory however is also not strong.
SYMPTOMS -: the sudden onset of pain (often in the hindquarters) associated with exercise. The severity ranges from a reluctance to move to extreme pain and absolute immobility ( so bad in fact the horse may need to be floated back to the stables), swellings (small or diffuse) under the skin; urine turns a brownish to burgundy coloration due to the excretion of myoglobin. Other problems may also rise in the form of myoglobin forming crystals and blocking the renal tubules in the kidneys thereby causing renal failure.
Tying-Up can be prevented in most horses through the reduction of the amounts of grain fed during rest or idle periods and adequate warming up before a period of exercise is also recommended before the exercise commences. This can help in horses that continually tie up, but in others it does not take much to trigger the condition.
TREATMENT -: the recommended treatment for tying-up is a definite Veterinarian matter. The vet should be called so that pain killing drugs may be administered to alleviate the pain. He may also administered B vitamins (especially B1) corticosteroids, antihistamines and perhaps Sodium Bi-Carbonate to counteract kidney problems.
LAMINITIS
Also known as 'founder', chronic forms of this condition are also know as 'slipper toe' and another more commonly known name of 'seedy toe'.
Laminitis is an inflammation and separation of the laminae of the hoof. It can be either acute or chronic. In the acute form laminitis is extremely painful and affected horses display anxiety, trembling, increased breathing rate and have a raised temperature and severe diarrhoea. Symptoms of acute laminitis occur about 12-18 hours after grain is eaten.
Seedy toe and slipper toe are the chronic forms of the condition. The term seedy toe refers to the separation of the laminae at the front of the hoof with the subsequent entry of pathogens which set up an infection. Slipper toe is also a chronic condition where the front of the hoof grows out because the horse finds it less painful to rest its weight on the heels. After several years of being in this condition the foot grows to form a slipper like projection and the toe turns up.
The cause of laminitis may be caused my a variety of agents. The nutritional causes are probably related to disturbances of the microbial population in the hindgut after eating large amounts of starch. The grains most often or more commonly associated with the onset of this condition are wheat, corn or barley or pig or fowl feeds contain large quantities of these grains. Oats does not often cause founder (due to the high fiber content and being harder to digest and extract starch from). Other causal factors are infections, hormone status (oestrogens) and possibly treatments with corticoids and phenylbutazone.
Onset of the condition is rapid and palliative measures must be undertaken if you think that founder may occur.
Grass founder may be caused by horses eating grass rich in soluble sugars (fructans) and starch. It may also be caused from horses eating huge amounts of lush green pasture particularly after a dry spell and the result is enterotoxaemia from the huge amounts of soluble sugars, or may be from the hormonal changes accompanying obesity (most affected horses are generally obese), or may even be cause through castration of colts ( a common condition in geldings) or to oestrogens present in some clovers. The symptoms occur more slowly than from grain founder, and there is generally no scouring
Water founder may well be the result of allowing overheated horses drink large quantities of water. e.g. immediately after exercise. The cause is unknown, but it may be related to bacterial metabolism in the hindgut.
FEED RELATED TEMPERAMENT PROBLEMS
There is little evidence that particular feeds cause temperament problems in horses, though I am aware and fairly sure there are many of you out there that will totally disagree with this. Although one view is that a horse which is fed well, i.e. given an energy-rich diet will have enough energy to display its normal aggressiveness if it has that type of nature - though this is one aspect of horse ownership that totally contradicts itself- though this may be a 'scientific' aspect, the more common sense and more likened horseman in me comes to the fore here and will totally disagree with this theory. The contrary view is based on anecdotal but frequent observations that particular feeds do in fact cause temperament problems. I am a great believer that absolutely NO horse has that sort of inherent temperament problem, that is of being aggressive towards humans. If a horse does in fact display these traits, it is always trying to tell you something. Maybe the horse is hurting, maybe the horse is totally unbalanced in the diet it is being fed, there are a myriad of things it could be. Do not immediately dismiss it as simply being the 'temperament of the horse'.
Oats is often cited as being the most common grain 'my horse can't have', but have also found it interesting that no two horse owners will rank cereal grains in the same order and other will suggest corn or barley, molasses, protein meals etc. as being the cause of their hors's behavior.
If there is in fact a relationship between horse temperament and breeds, which is independent of energy supply and is related to some chemical characteristic of feeds, it is difficult to see what that might actually be. Two theories are -:
1. Lactic acid accumulation - the evidence is extremely scant in this instance though, and there has been only one report which suggests that lactic acid may be involved.
2. Ammonia accumulation in the blood - it has also been suggested that horses supplied high protein diets will consequently have high blood ammonia levels thereby causing a more temperamental condition.