Selenium deficiency.
D000821:Animal Feed; D000818:Animals; D005260:Female; D006734:Horse Diseases / Q000209:etiology*; D006736:Horses; D009137:Muscular Dystrophy, Animal / Q000209:etiology*; D011247:Pregnancy; D011248:Pregnancy Complications / Q000662:veterinary; D012643:Selenium / Q000172:deficiency*
D012643:Selenium