Excess protein is excreted via the urine and manure. To do so it must first be converted to urea and ammonia by the liver. A blood test can show if a horse is getting too much protein by having high levels of blood urea and ammonia. However, if a horse is not receiving enough dietary energy, they will break down body tissues to compensate and this will also show elevated levels of blood urea and ammonia.
Research suggests that daily over feeding of protein surpasses the ability of the liver to convert protein to urea and ammonia for excretion in the urine. This is an added burden to the liver and kidneys. High gut urea levels also causing an increase in intestinal disturbances and cause a decrease or loss of appetite and also be on of the cause of bursting (internal bleeding).
Water and electrolytes are required to excrete the extra urea and ammonia, causing an additional demand on body reserves of both. Obviously increasing urinary output. However, if the horse has a kidney weakness and is unable to handle the excess there will be a build up of lactic acid, resulting in loss of performance or even ´tying-up´ (Azotoria) and simply fading at the end of a race or hard work. Irritable behaviour, nervousness or restlessness are all signs of high urea and ammonia in the blood. This can disturb energy production during exercise.
High ammonia in the urine quite obviously contaminates the stable environment. In warm weather especially the fumes affect humans and horses alike. There is an increased risk of respiratory conditions, infections and viruses. Calcium deficiency can be caused by excess protein. It has been found to leach calcium from the body due to the increase in uric acid. This causes poor bone density, weak lung walls, weak bowel walls and can lead to 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.”
Foals and weanlings require 14% protein, 2 and 3 year-olds 14-16% maximum, adults (4 years up) 10 to 12%.
Alfalfa contains 18 to 24% protein, so you can see how feeding a diet of straight alfalfa or even 50% alfalfa, will cause acidosis in the body. Most horses can cope with about 10-12% of the forage part of their diet being alfalfa.
horses that are Cushing's/hypothyroid/insulin resistant ("easy keepers") do best on no alfalfa at all. Also those fighting off serious infection like West Nile Virus or recovering from colic surgery, recover much better on straight grass hay.
Alfalfa typically contains inappropriate levels of calcium to phosphorus, 5:1 to be exact. A balanced ratio of calcium to phosphorus is 1.5 parts calcium to 1 part phosphorus. The excess calcium in alfalfa interferes with parathyroid function and can lead to thumps, muscle cramps and tying up.
Excess calcium also interferes with the absorption of iodine, a mineral necessary for proper thyroid function. Many horses on a high alfalfa diet become hypothyroid as the thyroid gets lazy and tired from being malnourished. Symptoms are cresty necks, overweight/easy keepers yet always hungry, dry, flaky skin, “cinchy” and skin-sensitive, loss of top line muscling and hair condition and unwillingness to give and flex due to increased water retention.
“According to research performed at Colorado State University and in Sweden, excess dietary protein decreases T4 levels. Optimum T4 levels are necessary for horses to metabolize glucose (blood sugar) properly. When a horse is under strenuous exercise, higher glucose levels are required to fuel the muscles. Higher glucose levels also delay the onset of lactic acid buildup in the muscles and blood. Too much lactic acid causes the muscles to lose their ability to contract and relax properly. In this state the muscles stay contracted/tied up.”
Too much calcium also depletes magnesium, which is absolutely essential to relax muscles after the contraction phase, during work. In the studies in Sweden and Colorado State University higher magnesium levels were found to increase production of T4 thyroid hormone. My clients and regular readers all know how much I sing about the properties of giving magnesium in the diet.
By simply removing the alfalfa in the diet often clears up scratches!
Does your horse have thick foamy sweat? If he does look at his protein levels. When using excess protein for energy the nitrogen end of the protein strand is cut off, separating the nitrogen from the amino acids. They are necessary for metabolic function, while excess nitrogen forms urea (non-protein nitrogen), which is removed from the bloodstream by the kidneys. It becomes priority to flush the toxic ammonia that was produced in this process over retaining water for hydration of the muscles. The horse will drink lots of water and urinate more frequently which leads to dehydration. The visual result being thick, foamy sweat, which does not cool a horse as effectively as thin, watery sweat. In turn this causes them to sweat more which dehydrates the body further still.