Humans as well as horses need it and if they have a lack or an oversupply of it this can cause acute problems. Due to this it is important that riders inform themselves about the symptoms of a possible disease and about the right dosage of selenium.
Lack of selenium has its origins in the soil…
A Lack or an oversupply of selenium both can cause serious problems for the organism of a horse. In general due to many sandy soils horses more often have a lack of selenium. Strew and hay as well as cereals do not offer enough of selenium if they grow out of sandy and not out of fertile ground. Today farmers cultivate too many cereals on their fields so that the soil loses its natural balance and cannot offer enough selenium and other trace elements. In Germany this especially refers to fields in the south because here the lack of minerals is even higher than in the north of Germany. Horse owners need to consider all these facts if they want to feed their horses in an optimal way. Horses need a combination of minerals and pellets but it is important to know about the quantity.
Selenium and its function in the organism
Medical research about the functions of selenium is not completed so that until today there still is a lack about all of the functions of this important mineral. Nevertheless the following ones are for sure: The main function of selenium is to guarantee the correct work of the Glutathione Peroxidase. This is an enzyme and takes part in the reduction of radicals and metabolites which arise from metabolic processes or infectious diseases. Due to this radicals are waste products and destroy functional cells in the whole organism. The enzyme Glutathione Peroxidase inhibits the radicals so that it guarantees a functional organism. Referring to this selenium has an important role in the immune defense what already offers its great significance.
How does a horse get a lack of selenium and what are the symptoms?
As already explained fodder with a lack of minerals (selenium) often causes a selenium deficiency. Additionally there can be other reasons: due to its function in the organism it is responsible for the reduction of toxic substances. Referring to this vets advise to feed selenium if a horse ate cadmium, lead, tin or mercury. Furthermore horses which strain their muscles (p.e. because of an extreme training) often provide a lack of selenium. In this case the organism produces many radicals and it needs a lot of selenium for the reduction. Moreover radicals are results of other diseases like infectious diseases or cancer. Finally one can see that the function of selenium has a great significance because a deficiency easily causes a disease or susceptibility for allergies.
Generally it can be difficult to diagnose a selenium deficiency. Even if there are some particular symptoms some horses only become tired, sluggish and slowly. Nevertheless some definite symptoms for a lack of selenium are:
- Muscle cramp which can look like a colic
- Dull hair
- Susceptibilities for infections
- Old horses have the same symptoms as in cases of an Equine Exertional Rhabdomyolysis
- Damage of muscle cells in the area of the skeleton and the heart
During the first days of their life foals often have a lack of selenium. This is explainable through a selenium deficiency of the mother during the period of pregnancy: the placenta could not offer enough selenium for both the foal and the mother. In these cases foals walk in a stiff way and can hardly drink the milk of their mother. Vets call this a degeneration of the muscles due to wrong nourishment. To provide a good start into their life it is really important to recognize the lack of selenium and to feed against it.
But also an overdose is dangerous!
Indeed it is really difficult to feed the right quantity of selenium: the difference between the right quantity and a chronic and therefore toxic overdose is nearly nothing. The daily need of a horse is between 0,15- 0,2 mg per one kilogram of fodder. In opposite to this 2 mg per one kilogram of fodder already causes an overdose. This can happen if horse owners feed a too high quantity of pellets or mineral fodder and in some cases it even results in an acute poisoning. Referring to this it is recommended to inform yourself about the exact quantity of selenium in pellets or mineral fodder. Typical symptoms for an overdose are:
- Constriction in form of a ring around the hoof
- Swelling of the hooves and possible bleeding
- Often an ulcer of the hooves
- Unspecific lameness
- Friable hooves
- Loss of hair
- Apathy and loss of appetite
Tipp! Normally many blood screenings depict a too high data of selenium in the organism. If you want to have correct information you need to analyze the screening considering the data of zinc, copper and manganese. In the past researchers recognized that a lack of these three elements caused a too high data of selenium in the blood screening. Due to this it may help to feed copper, zinc and manganese to lower the data of selenium.