title: Effect of a monensin-controlled release capsule on cow health and reproductive performance.
abstract: Dry cows and pregnant heifers from 25 farms near Guelph, Ontario, Canada were enrolled in a large, double-blind, randomized clinical trial designed to evaluate the impact of monensin on energy metabolism, health, and production. A total of 503 cows was given monensin in controlled-release capsules, and 507 cows were administered placebo capsules 3 wk before expected calving date. The effects of treatment on health were evaluated using a logistic regression model. Treatment with monensin significantly reduced the incidence of abomasal displacement (OR = 0.41-0.84) and multiple illnesses (OR = 0.38-0.89). Monensin treatment tended to reduce the incidence of clinical ketosis (P = 0.11) and the risk of being culled (P = 0.09) in the first 94 d of lactation. Reproductive performance was analyzed with both a logistic regression model for conception rate and a survival analysis for days to first breeding and days from calving to conception. Treatment with monensin had no significant effect on any measure of reproductive performance.
authors.affiliation: Department of Population Medicine, Ontario Veterinary College, University of Guelph, ON, Canada.
authors.forename: T F
authors.initials: TF
authors.lastname: Duffield
authors.forename: K E
authors.initials: KE
authors.lastname: Leslie
authors.forename: D
authors.initials: D
authors.lastname: Sandals
authors.forename: K
authors.initials: K
authors.lastname: Lissemore
authors.forename: B W
authors.initials: BW
authors.lastname: McBride
authors.forename: J H
authors.initials: JH
authors.lastname: Lumsden
authors.forename: P
authors.initials: P
authors.lastname: Dick
authors.forename: R
authors.initials: R
authors.lastname: Bagg
mesh_terms: D000018:Abomasum; D000818:Animals; D002417:Cattle / Q000502:physiology*; D002418:Cattle Diseases / Q000517:prevention & control*; D003692:Delayed-Action Preparations; D004311:Double-Blind Method; D004734:Energy Metabolism / Q000187:drug effects; D005260:Female; D007662:Ketosis / Q000517:prevention & control / Q000662:veterinary; D016015:Logistic Models; D008985:Monensin / Q000008:administration & dosage* / Q000627:therapeutic use; D011247:Pregnancy; D012098:Reproduction / Q000187:drug effects*; D013272:Stomach Diseases / Q000517:prevention & control / Q000662:veterinary
chemical_list: D003692:Delayed-Action Preparations; D008985:Monensin