title: Effect of a prepartum administration of monensin in a controlled-release capsule on apparent digestibilities and nitrogen utilization in transition dairy cows.
abstract: The influence of a monensin controlled-release capsule, which was administered 3 wk before the calving date, on diet digestibility and nitrogen utilization was investigated in 16 multiparous dairy cows between approximately 10 and 3 d precalving and 3 and 9 d postcalving. Monensin decreased rumen ammonia from 5.4 to 3.2 mg dl(-1) precalving and from 6.0 to 4.9 mg dl(-1) postcalving. Blood urea concentrations were increased by monensin from 4.93 to 5.28 mM precalving and from 5.27 to 5.81 mM postcalving, but these increases were not statistically significant. Precalving, monensin increased the apparent digestibilities of neutral detergent fiber from 52.8 to 62.1%, of acid detergent fiber from 50.7 to 58.7%, and of gross energy from 60.5 to 66.7%. Postcalving, monensin increased the apparent nitrogen digestibility from 63.7 to 71.5%, which resulted in an improvement in the nitrogen balance from -77.8 to -44.9 g d(-1). The monensin controlled-release capsule contributed to increasing the availability of dietary nitrogen to the transition dairy cow during the critical postcalving period.
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: 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: D000641:Ammonia / Q000378:metabolism; D000818:Animals; D001806:Blood Urea Nitrogen; D002214:Capsules; D002417:Cattle; D003692:Delayed-Action Preparations; D004043:Dietary Fiber / Q000378:metabolism; D004063:Digestion / Q000187:drug effects*; D005260:Female; D008985:Monensin / Q000008:administration & dosage / Q000494:pharmacology*; D009584:Nitrogen / Q000378:metabolism*; D049590:Postpartum Period; D011247:Pregnancy; D012417:Rumen / Q000378:metabolism
chemical_list: D002214:Capsules; D003692:Delayed-Action Preparations; D004043:Dietary Fiber; D000641:Ammonia; D008985:Monensin; D009584:Nitrogen