title: Sustained-release boluses to supply trace elements and vitamins to calves.
abstract: Cylindrical rumen boluses of a size (55 mm length x 18 mm diameter, density 2.9 g cm(-3)) appropriate for ruminating calves over 75 kg liveweight were constructed. The mean daily nutrient releases from two rumen boluses measured in rumen-cannulated cows were 62 mg Cu, 0.56 mg Se, 1.08 mg Co, 1.14 mg I, 38 mg Mn and 55 mg Zn with vitamins 3140 IU A, 628 IU D3 and 9 IU E. In a 123-day experiment with housed dairy calves given hay and a barley/soyabean meal mix, administration of two rumen boluses significantly increased plasma copper and blood glutathione peroxidase levels compared with unsupplemented control calves. There were similarly significant responses in a 143-day experiment with suckled beef-cross calves treated with two rumen boluses at grass. In both circumstances the basic diets provided inadequate allowances of both copper and selenium.
authors.affiliation: Department of Veterinary Clinical Studies, Glasgow University Veterinary School, Bearsden, Glasgow G61 1QH, Scotland, UK.
authors.forename: R G
authors.initials: RG
authors.lastname: Hemingway
authors.forename: J J
authors.initials: JJ
authors.lastname: Parkins
authors.forename: N S
authors.initials: NS
authors.lastname: Ritchie
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D002417:Cattle / Q000502:physiology*; D003300:Copper / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology; D003692:Delayed-Action Preparations; D005979:Glutathione Peroxidase / Q000032:analysis / Q000494:pharmacology*; D009752:Nutritional Status; D018529:Nutritional Support / Q000662:veterinary; D012417:Rumen; D014131:Trace Elements / Q000008:administration & dosage* / Q000494:pharmacology
chemical_list: D003692:Delayed-Action Preparations; D014131:Trace Elements; D003300:Copper; D005979:Glutathione Peroxidase