title: Short communication: effects of monensin on 3-methylhistidine excretion in transition dairy cows.
abstract: Urinary 3 methyl-histidine excretion was measured in high yielding dairy cows between 10 and 3 d precalving and between 3 and 9 d postcalving. Cows received a sodium monensin controlled-release capsule or a placebo 3 wk before calving. Monensin did not affect urinary 3 methyl-histidine. Average urinary 3 methyl-histidine excretion was significantly higher postcalving (4.11 mmol d(-1)) than precalving (2.48 mmol d(-1)). This increase is assumed to be predominantly due to the negative nitrogen balance in the postcalving period caused by insufficient nutrient intake to meet nutrient requirements, which necessitates catabolism of mainly myofibrillar protein.
authors.affiliation: Department of Animal and Poultry Science, University of Guelph, ON, Canada.
authors.forename: J C
authors.initials: JC
authors.lastname: Plaizier
authors.forename: J P
authors.initials: JP
authors.lastname: Walton
authors.forename: A
authors.initials: A
authors.lastname: Martin
authors.forename: T
authors.initials: T
authors.lastname: Duffield
authors.forename: R
authors.initials: R
authors.lastname: Bagg
authors.forename: P
authors.initials: P
authors.lastname: Dick
authors.forename: B W
authors.initials: BW
authors.lastname: McBride
mesh_terms: D000818:Animals; D002417:Cattle / Q000502:physiology* / Q000652:urine; D003692:Delayed-Action Preparations; D004734:Energy Metabolism; D005260:Female; D007476:Ionophores / Q000008:administration & dosage / Q000494:pharmacology*; D007743:Labor, Obstetric / Q000378:metabolism*; D007774:Lactation / Q000652:urine; D008762:Methylhistidines / Q000652:urine*; D008985:Monensin / Q000008:administration & dosage / Q000494:pharmacology*; D009584:Nitrogen / Q000378:metabolism*; D011247:Pregnancy; D011506:Proteins / Q000187:drug effects / Q000378:metabolism
chemical_list: D003692:Delayed-Action Preparations; D007476:Ionophores; D008762:Methylhistidines; D011506:Proteins; D008985:Monensin; C028118:3-methylhistidine; D009584:Nitrogen