title: Effect of dietary sulfur and selenium concentrations on selenium balance of lactating Holstein cows.
abstract: The effects of dietary sulfate and selenium concentrations on selenium balance in dairy cows were investigated. Midlactation Holstein cows (n = 30) were fed diets containing either 0.1 or 0.3 mg of supplemental Se (from sodium selenate)/kg of dry matter and 0, 0.2, or 0.4% added S from a mix of calcium and magnesium sulfate in a factorial arrangement. The experiment lasted 112 d. Dry matter intake was linearly reduced with increasing S, but the effect was greater when 0.3 mg/kg of Se was fed (significant interaction). Treatment effects for yields of milk, milk fat, and milk protein were similar to those for dry matter intake. Increased dietary S linearly reduced plasma Se concentrations. Increasing dietary S linearly reduced apparent (42.7, 33.1, and 30.1%) and estimated true (50.5, 46.0, and 42.3%) Se digestibility. Excretion of Se via feces (1.6 vs. 2.8 mg/d) and urine (0.5 vs. 1.3 mg/d) was higher and output in milk (0.4 vs. 0.3 mg/d) was lower for cows fed 0.3 mg/kg of Se compared with 0.1 mg/kg, but no Se effect was found for estimated true Se digestibility. Dietary S from sulfate reduced Se balance especially when cows were fed diets with less than 0.3 mg of Se/kg of diet dry matter.
authors.affiliation: Department of Animal Sciences, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster 44691, USA.
authors.forename: J
authors.initials: J
authors.lastname: Ivancic
authors.forename: W P
authors.initials: WP
authors.lastname: Weiss
mesh_terms: D000818:Animals; D002417:Cattle / Q000378:metabolism* / Q000502:physiology; D004435:Eating / Q000187:drug effects*; D005260:Female; D007774:Lactation / Q000502:physiology*; D016014:Linear Models; D008055:Lipids / Q000032:analysis; D008892:Milk / Q000737:chemistry; D008894:Milk Proteins / Q000032:analysis; D012643:Selenium / Q000494:pharmacology*; D013455:Sulfur / Q000494:pharmacology*
chemical_list: D008055:Lipids; D008894:Milk Proteins; D013455:Sulfur; D012643:Selenium