Evaluation of the risk of motor neuron disease in horses fed a diet low in vitamin E and high in copper and iron.
OBJECTIVE
To determine whether equine motor neuron disease (EMND) could be induced in adult horses fed a diet low in vitamin E and high in copper and iron.


METHODS
59 healthy adult horses.


METHODS
Horses in the experimental group (n = 8) were confined to a dirt lot and fed a concentrate low in vitamin E and high in iron and copper in addition to free-choice grass hay that had been stored for 1 year. Control horses (n = 51) were fed a concentrate containing National Research Council-recommended amounts of copper, iron, and vitamin E. The hay fed to control horses was the same as that fed to experimental horses, but it had not been subjected to prolonged storage. Control horses had seasonal access to pasture, whereas experimental horses had no access to pasture. Horses that developed clinical signs of EMND were euthanatized along with an age-matched control horse to determine differences in hepatic concentrations of vitamin E, vitamin A, copper, iron, and selenium.


RESULTS
4 experimental horses developed clinical signs of EMND. Plasma concentrations of vitamin E decreased in all 8 experimental horses. There were no significant changes in plasma concentrations of vitamin A, selenium, and copper or serum concentrations of ferritin. There were no significant differences in those analytes between experimental horses with EMND and experimental horses that did not develop EMND. No control horses developed EMND.


CONCLUSIONS
Results suggest that lack of access to pasture, dietary deficiency of vitamin E, or excessive dietary copper are likely risk factors for EMND.
Divers
Thomas J
TJ
Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
Cummings
John E
JE
de Lahunta
Alexander
A
Hintz
Harold F
HF
Mohammed
Hussni O
HO
D000818:Animals; D003300:Copper / Q000633:toxicity; D004032:Diet / Q000662:veterinary*; D005293:Ferritins / Q000097:blood; D006734:Horse Diseases / Q000209:etiology* / Q000378:metabolism; D006736:Horses; D007501:Iron / Q000633:toxicity; D008099:Liver / Q000378:metabolism; D016472:Motor Neuron Disease / Q000209:etiology / Q000378:metabolism / Q000662:veterinary*; D018570:Risk Assessment; D012643:Selenium / Q000097:blood / Q000378:metabolism; D014801:Vitamin A / Q000097:blood; D014811:Vitamin E Deficiency / Q000097:blood / Q000662:veterinary
D014801:Vitamin A; D003300:Copper; D005293:Ferritins; D007501:Iron; D012643:Selenium