All animals exposed to high selenium at risk of development of clinical signs. In other areas—the Midwest for example—selenium is deficient in the soil, and without proper supplementation horses can have significant problems. Proof was soon obtained that selenium was the cause of alkali disease. intensive research was

The first sign of selenium toxicity is loss of mane and tail hair; in extreme cases, the hooves will slough off and the horse will have to be euthanized. Selenium Selenium intake: 0.5-2.0 mg/kg bodyweight. Acute toxicity can occur after a single dose, whereas chronic toxicity often develops over prolonged periods (>30 days). Adult horses should not get more than 5mg per day. Timecourse. The recommended minimum daily intake of selenium for an average sized, idle, adult, nonbreeding horse is 1 mg/day, or 0.1 mg/kg (= 0.1 ppm) in the total diet. The 21 polo ponies that dropped dead at the U.S. Open Polo Championship in Wellington, Fla., eleven days ago most likely succumbed to an overdose of selenium, used to … There is more data on the toxicity of Se in cattle and sheep, but selenosis affects all livestock. A condition called Amyotrophic Lateral Sclerosis, also called ALS or Lou Gerig's disease, is particularly linked to selenium poisoning- although any range of neurologic problems could be due to selenium toxicity. Diagnosis It was also shown that certain plants accumulated selenium in relatively large concentrations. Selenium is a mineral found in the soil in many areas of the country.

Above 20mg per day can cause chronic selenium poisoning. The toxicity and deficiency sections are general information and contain diseases that affect most species; for species specific diseases, see that species' section. Selenium toxicity from properly formulated and manufactured supplements, grains or from hays is virtually unheard of, even if you use more than one source of selenium. In selenium rich environments, the plants will absorb this metal from the soil, posing a risk to horses that graze there. Toxicity is more common in dry regions and in these situations, horses can suffer from “alkali disease” in which excessive selenium causes a loss of hair on the mane and tail, lameness and bone lesions, including twisted legs in foals and sloughing of hooves (Frape., 1998). What Dosages cause Selenium Overdose. The most serious toxicity symptoms are neurologic problems. Toxicity: The margin between ideal and toxic levels of selenium is very slight, and selenium toxicity can be far more dangerous than a deficiency.

Symptoms of toxicity include heart and liver damage; degeneration of bones, joints, and muscles; cracking or … Lameness, loss of appetite, partial blindness, staggering and paralysis are all indicators of severe selenium poisoning. Selenium toxicity is a serious threat to livestock in the western United States. Magnesium is another commonly overfed mineral. One can counter high Se levels by feeding a mineral high in sulfur.