title: Blindness and convulsions associated with vitamin A deficiency in feedlot steers.
abstract: Blindness and convulsions were the predominant clinical signs in a group of feedlot steers inadvertently fed a vitamin-A deficient diet. Although vitamin A had been added to the feed at the time of preparation, it was believed that the vitamin A had been destroyed by heat, humidity, and minerals mixed in the feed. Feedlot heifers fed the same high-grain diet were clinically normal, and one heifer from which a blood sample was obtained had normal serum vitamin A content. The ingestion of sparse grasses and weeds found along the fence row of the heifers' pens was thought to have provided sufficient vitamin A to these animals. This episode demonstrated the importance of monitoring vitamin A and vitamin A precursor concentrations in stored feeds, especially those stored under adverse conditions and those fed to animals ingesting only a high-grain diet.
mesh_terms: D000821:Animal Feed; D000818:Animals; D001766:Blindness / Q000209:etiology / Q000662:veterinary*; D002417:Cattle; D002418:Cattle Diseases / Q000209:etiology*; D005260:Female; D008297:Male; D012640:Seizures / Q000209:etiology / Q000662:veterinary*; D014801:Vitamin A / Q000032:analysis; D014802:Vitamin A Deficiency / Q000150:complications / Q000662:veterinary*
chemical_list: D014801:Vitamin A