title: Factors affecting serum selenium and vitamin E concentrations in dairy cows.
abstract: Supplementation of selenium and vitamin E to enhance disease resistance in dairy cattle has become common, particularly to prevent periparturient reproductive disorders and mastitis. To establish reference values for serum vitamin E and selenium concentrations in postparturient dairy cattle and to determine whether serum concentrations of these micronutrients varied with season and stage of lactation, cows from a stratified random sample of 50 herds were studied for 1 year. Blood samples were collected from each of the 50 study herds twice, from the 10 most recently parturient cows or from 10% of the herd, whichever was greatest. Mean concentration of vitamin E and selenium was 2.55 micrograms/ml and 78.12 ng/ml, respectively. Vitamin E concentrations were significantly (P < 0.05) higher during the summer and fall than during the winter and spring. Selenium concentrations were significantly (P < 0.05) lower during the summer and fall than during the winter and spring. Herd, season of blood sample collection, and time since parturition were significant (P < 0.02) in explaining variation in vitamin E and selenium concentrations.
authors.affiliation: Department of Veterinary Preventive Medicine, College of Veterinary Medicine, Ohio State University, Columbus 43210, USA.
authors.forename: G Y
authors.initials: GY
authors.lastname: Miller
authors.forename: P C
authors.initials: PC
authors.lastname: Bartlett
authors.forename: R J
authors.initials: RJ
authors.lastname: Erskine
authors.forename: K L
authors.initials: KL
authors.lastname: Smith
mesh_terms: D000818:Animals; D002417:Cattle / Q000097:blood*; D005260:Female; D007774:Lactation / Q000097:blood*; D016014:Linear Models; D015999:Multivariate Analysis; D012016:Reference Values; D012621:Seasons; D012643:Selenium / Q000097:blood*; D012984:Software; D014810:Vitamin E / Q000097:blood*
chemical_list: D014810:Vitamin E; D012643:Selenium