The effects of feeding excess dietary protein
The latest research on protein in horses indicates that excess dietary protein, especially processed, can have several damaging effects. These include:
(1) High blood urea and ammonia levels: Protein that is over what is required must be excreted via the urine and the manure. For this to be done it must first be converted to urea and ammonia by the Liver. High blood urea and ammonia levels on a blood test can indicate that the horse is getting too much protein in the diet. However, if horses are getting insufficient dietary energy and are breaking down body tissues for energy, this will also elevate blood urea and ammonia levels.
(2) Liver and Kidney stress: Recent research suggests that over feeding of protein per day exceeds the ability of the liver to convert protein to urea and ammonia for excretion in the urine. This places and added burden on the liver and the kidneys, and high gut urea levels can increase intestinal disturbances, and can be one of the causes of both ‘hanging’ or ‘bursting’ and also loss or decrease in appetite.
(3) Increased fluid and electrolyte demands: To excrete the extra ammonia and urea requires electrolytes and water. This places an added demand on body water and electrolyte reserves and increases urinary output. If, however the horse has a kidney weakness and is unable to handle the excess urea or ammonia there will be a build up of lactic acid with the resulting loss of performance or even 'tying-up', ‘Azotoria’ and ‘bursting’ or simply fading at the end of a race.
(4) Nervous irritability: High urea and ammonia in the blood affect the nervous system, causing irritable behaviour and restlessness, and can disturb energy production during exercise.
(5) Increased risk of respiratory conditions: High ammonia in the urine contaminates the stable environment. This is especially noticeable in warm weather, the ammonia fumes affect humans and horses alike, irritating the eyes and respiratory system and predisposing to respiratory infections and viruses.
6) Poor performance: Studies in America have demonstrated that feeding excess nitrogen over recommended levels can prolong racing times by up to 3 seconds.
(7) Excess protein can cause calcium deficiency: Feeding excess protein has been found to leach calcium from the body due to increase in Uric Acid causing poor bone density, weak lung walls, weak bowel walls and can lead to internal bleeding i.e. 'bursting' and bone fractures.
Research in America has shown that 30% of all the horses bone scanned showed hairline fractures of the lumbar vertebrae over the kidney/loin area. This is due to stress, standing starts, (starting stalls) and partly due to diet, the diet that starts in the paddocks not just in training, Many horses have an inherited kidney weakness and this shows up very clearly in an Iris diagnosis (Iridology) and these horses are more prone to suffering from permanent muscle damage. An inherited kidney weakness can lead to a build up of lactic acid causing Azotoria or ‘tying up’ and pain over the loin area. Myositis which is inflammation of the muscles, in this case the longissimus dorsi (this muscle stretches from the sacrum and ileum to the neck, making it the largest and longest muscle in the body), and psoas muscles, ( the Psoas major flexes the hip joint and rotates the thigh outward, while the Psaos minor flexes the pelvis on the loins and inclines it laterally) the inflammation is caused from stress, i.e. fast starts from standstill, and in some cases it can be secondary to degeneration of bones or joints, Azotoria and ‘tying up’ can also cause inflammation to these back muscles and if not given enough time and treatment can form permanent muscle/kidney damage.
Adult horses (4 years up) only require between 10 and 12% protein, foals and weanlings 14%, 2 and 3year olds 14-16% maximum. Older horses can absorb 12%.
To over supplement is having an extra handicapper!
The horse that is in any form of hard work, i.e. racing, endurance, eventing, has increased requirements for nutrients to perform hard exercise, but over supplementing above their requirements cannot improve performance. A surplus is equally as dangerous as a deficiency, such that a delicate balance is required between feeding enough to ensure best results and overfeeding enough to cause disorders and inhibit performance.
78% of horses fed supplements are likely to receive excess energy, protein and an imbalance of minerals. Excessive levels of individual nutrients occur up to 10 times more frequently when supplements are added, which if incorrectly balanced can still cause deficiencies. Using several supplements can lead to overlap and hence an increased risk of excesses and sub clinical toxicity
For example: an EXCESS of the following can induce:
Iron - selenium, copper, zinc, phosphorous (leading to poorly
mineralised bone) and Vitamins E and B12 deficiencies.
Protein - reduced muscle energy levels; prolonged race times; respiratory
irritation; body fluid and electrolyte loss.
Iodine - contracted tendons, hair loss, goitre.
Copper - reduced liver function.
Electrolytes - dehydration.
Cobalt - depressed red cell production, fatigue, weakness and loss of appetite.
Selenium - dullness, depression, loss of appetite, weight loss, hoof damage, lameness.
Magnesium - interferes with the levels of sodium and potassium.
Manganese - Nervous problems, muscle tremors and anaemia.
Fluorine - diarrhoea, bone lesions, lameness and general unthrift ness.
Vitamin A - depressed growth, reduced iron, low red cell count, lameness.
Vitamin K - colic, laminitis, kidney damage.
Vitamin D - calcium deposition in blood vessels, heart, lungs, kidneys, weight loss bone and joint damage.
Vitamins and minerals which are all available in herbal form are 100% safe and absorbable simply because having already been digested once by the plant they are easier to absorb by the horse and any excess that are not needed will be easily flushed out by the kidneys or through the bowels.
It has been found after research into horses that ‘burst’ that a much higher percentage, 78% responded to treatment when fed on a majority oat ration, whereas with horses fed on processed concentrates, the response to treatment was much lower approx only 25%.