Horses with a kidney disease: symptoms, diagnosis, treatment

The kidney is the organ which detoxifies the body. If the kidney is ill harmful substances stay in the organism and other organs get damaged. Indeed horses do not often have an inflammation of the kidney. Moreover the symptoms for this disease are quite unspecific so that generally it is really difficult to make an early diagnosis. The inflammation can lead to a chronic kidney disease which, in worst case, ends with the death.


A disease of the kidney has influence on the whole body and organism. It is really difficult to make an early diagnosis because the blood screening offers first hints when the situation of the disease already is quite advanced. In general a kidney disease is irreversible what means that damaged cells are not able to recover and the organ cannot provide its entire functionality anymore.

Function of the kidney in the organism

Humans and horses have two kidneys. On the right side it has the shape of a heart and on the left side it can be compared with the shape of a bean. The most important function of the kidney is the detoxification of the blood. Every day nearly 6600 liters flow through the kidney of the horse. The organ filters the blood and cleans it from degradation products of several metabolic processes. Especially the final degradation product of the protein metabolism, so called as urea, gets separated from the blood. The urea accumulates inside the kidney (renal pelvis) before it leaves the body through the ureter and the bladder. According to this the kidney detoxifies the body from harmful and dangerous substances. Additionally it guarantees an ordered allocation of water and electrolytes in the organism and produces hormones.

Origins and reasons for a kidney disease

Mostly, a kidney disease is caused by prior inflammations or illnesses. The kidney itself gets influenced when it is overloaded. It is the excretory organ and needs to work even more when a bacterial infection or a poisoning enters the organism: it must not only filter the blood from the normal degradation products, but from further pathogens. The kidney is overloaded and finally dangerous and harmful substances stay inside the body and other organs easily become attacked. Moreover a long-termed use of medicine, especially if it is an antibiotic with toxic effect on the kidney, can cause a lasting damage. A further possible origin for the disease can be wrong feeding: the horse eats too many proteins which causes an increased number of urea (degradation product of the protein metabolism). The kidney needs to decompose the overdose of urea and consequently becomes overloaded. Additionally a wrong dose of calcium and vitamin D can be the origin of the insufficiency. An overdose causes lumpy deposits between the cells which limits the power of the tissue. Referring to this the same effects can be caused by a tumor. Furthermore not enough water, a colic or heart problems cause a disturbed circulation of the kidney. The oxygen supply gets interrupted what causes an immense damage of the cells. According to this the function of the whole kidney becomes limited. Any damage of the tissue cells is not curable so that a kidney disease is an irreversible illness.

Symptoms for an inflammation of the kidney

The great problem of a kidney disease is that there is a long time between the beginning of the disease and the first external symptoms. In fact this means that the right diagnosis often is really late. The symptoms are unspecific and this causes two problems at once: horse owners do not notice them at all or cannot find the origin. Sometimes it is not possible to clarify the symptoms until there already is a chronic situation of the disease. Then the blood screening shows an overdose of urea. The most clear symptom is when your needs to urinate really often and if there even is blood in the urine. In addition to this an increased demand of water can be a hint for a kidney disease. Further indications are:

  • Fever
  • Restlessness
  • Stick walk
  • Physical weakness/ tiredness
  • Lack of appetite
  • Loss of weight
  • Swelling of certain parts of the body
  • High blood pressure

Diagnosis of a kidney disease

Vets make use of a blood screening, an ultrasonic or an analysis of the urine for the diagnosis of a kidney disease. Referring to the blood screening one can specialize on relevant substances like creatinine, urea and certain electrolytes. It is really important that a vet is able to understand the information what means that he considers all substances and their respective influence on each other (it is not helpful to analyze one isolated data!). If the blood screening shows an overdose of urea this is a clear symptom for a kidney disease. Obviously the organ is not able to fulfill its function as a degradation organ anymore what causes an increased number of urea in the blood. Beside the blood screening vets additionally advice to make an ultrasonic. Then you get detailed information about the current situation of the kidney. The ultrasonic shows the shape of the organ what might help to see external mutations (e.g. caused by a tumor or kidney stones).

Possible treatment and therapy

A kidney disease is an irreversible illness what makes a quick therapy really important. A fast and effective treatment can avoid a high number of damaged tissue cells. In cases of an acute inflammation the vet injects a liquid infusion with physiological saline. If the kidney needs to deal with a poisoning the vet can inject the respective antidote. Most often there is a bacterial infection of the kidney and the vet administers antibiotics. Horse owners must always make sure that these antibiotics do not have any poisoning effects on the kidney!
Generally a long termed use of medicine can be the origin for a kidney disease. According to this horse owners should avoid a chemical medication but prefer medicinal plants and homeopathic compounds which support the immune system and the function of the kidney. Solidago herb (30-40g/day) and filipendua herb (30-40g/day) have detoxifying effects. Horse owners can mix these herbs with the normal hay and feed it for 6-8 weeks (two or three times a year and especially recommended if horses regularly take medicine). Additionally other plants like dandelion, birch leaves and stinging nettles are really useful for flushing out any kind of bacteria. Moreover you can feed garlic powder for 4-5 weeks (30-50g/day).
In any case one has to consult a vet before beginning with the respective treatment.

Chronic situation of a kidney disease

Unfortunately a horse easily can have a chronic situation of a kidney disease: until one can see any symptoms in the blood screening the function of the kidney has already been limited for a longer time. In lucky cases the inflammation affects only a small part of the tissue cells. Then, the kidney still has enough reserve so that it can fulfill its function in the organism unlimited. Furthermore one has to consider that there are two kidneys and according to this the other one is able to compensate a small damage (remember that humans can even survive with only one kidney). In opposite to this there are great problems when the inflammation affects big parts of the tissue cells. The organism reacts with an increased blood pressure and this leads to a vicious circle: the blood pressure destroys further cells so that the function of the tissue gets even more limited.
Generally a kidney disease can be separated into four categories. The transition between the respective categories can be smooth and it can be really difficult to notice them. The step from one category to the next one can be caused by certain happenings: the horse gets a high dose of medicine or has diarrhea.
The four categories are:

  1. Total compensation: some tissue cells already are damaged but the kidney has reserves and is able to compensate the damage. The function of the kidney seems normal. The blood screening does not show a high dose of urea.
  2. Compensated retention: the blood screening shows an overdose of urea. The horse does not suffer from any symptoms.
  3. Preterminal kidney failure: the blood screening shows a high overdose of urea. The horse suffers from the described symptoms.
  4. Terminal kidney failure: in this situation humans need to make a dialysis or a kidney transplant. Both options cannot be realized in veterinary medicine so that the disease leads to the death of the animal.

The classification into these four categories clarifies that there is a long time between the beginning of the disease and the first external symptoms. Referring to this the illness mostly already is in a dangerous situation and it can be too late for any help. The importance of an early diagnosis and the consultation of a vet becomes stressed.


As already described a kidney disease can be caused by toxic substances. Referring to this it is really important that horse owners check the environment of the horse and remove all toxic materials. One needs to make sure that:

  1. there are no mildews in hay or straw
  2. there are no poisonous plants on the pasture
  3. the horse regularly has a deworming

Generally horses easily lick on wood (e.g. in the stable) so one has to avoid poisoning substances in wood preservatives. The most important prevention against a kidney disease is right feeding: the daily ration may not have an overdose of proteins, calcium or vitamin D because the kidney needs a lot of energy to decompose these substances (it is recommended to consult a nutrition expert). Moreover any medicine needs to get checked (do not use any medicine with toxic effects on the kidney!) and horse owners need to avoid a long termed use of medicine at all. (Undoubtedly certain horses need a regular medicinal treatment. Nevertheless one can try to support the function of the kidney by feeding certain plants or homeopathic medicine –> please contact a vet!


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