title: Effects of prepartum somatotropin and monensin on metabolism and production of periparturient Holstein dairy cows.
abstract: Fifty-five multiparous Holstein dairy cows were used to evaluate the singular and combined effects of somatotropin and monensin treatments during the late dry period on postpartum metabolism and production. Treatments were 1) control (C); 2) injection of exogenous bovine somatotropin (bST); 3) TMR top dressed with 300 mg of monensin/day (M); and 4) monensin and somatotropin in combination (bST+M) during the last 28 days before expected parturition. A 500-mg subcutaneous injection of sustained release somatotropin was administered adjacent to the tail head at d -28 and -14 relative to expected calving. Diet and management were the same for all cows after parturition. Production and intake were measured daily until 63 d in milk. Milk composition, blood metabolites, and body weight and condition score were measured weekly. Prepartum glucose, nonesterified fatty acid, and blood urea nitrogen concentrations were not different among treatments. Cows on the M treatment tended to have greater dry matter intake postpartum than those on the C treatment and 30% lower plasma nonesterified fatty acid concentrations during wk 1 postpartum than all other treatments. Milk yield and milk fat yield were not different among treatments, but milk fat percent tended to be lower for the bST+M treatment than the C treatment. Changes in plasma amino acid concentrations were consistent with mobilization of skeletal muscle protein, possibly for use in gluconeogenesis. Results from this study provide evidence that prepartum feeding of monensin reduced plasma nonesterified fatty acid concentrations and may improve glucose metabolism of the periparturient dairy cow.
authors.affiliation: Department of Dairy and Animal Science, The Pennsylvania State University, University Park 16802, USA.
authors.forename: J E
authors.initials: JE
authors.lastname: Vallimont
authors.forename: G A
authors.initials: GA
authors.lastname: Varga
authors.forename: A
authors.initials: A
authors.lastname: Arieli
authors.forename: T W
authors.initials: TW
authors.lastname: Cassidy
authors.forename: K A
authors.initials: KA
authors.lastname: Cummins
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000032:analysis / Q000187:drug effects; D001806:Blood Urea Nitrogen; D001835:Body Weight; D002417:Cattle / Q000378:metabolism / Q000502:physiology*; D004435:Eating; D004734:Energy Metabolism / Q000187:drug effects*; D005227:Fatty Acids / Q000097:blood; D005260:Female; D013006:Growth Hormone / Q000494:pharmacology*; D007476:Ionophores / Q000494:pharmacology*; D007774:Lactation / Q000187:drug effects*; D008892:Milk / Q000737:chemistry* / Q000378:metabolism; D008985:Monensin / Q000494:pharmacology*; D011247:Pregnancy; D013997:Time Factors
chemical_list: D001786:Blood Glucose; D005227:Fatty Acids; D007476:Ionophores; D013006:Growth Hormone; D008985:Monensin